The poor prognosis of patients with soft-tissue sarcoma as not changed in the past several decades, highlighting the necessity for new therapeutic approaches. T-cell based immunotherapies are a promising alternative to traditional cancer treatments due to their ability to target only malignant cells, leaving benign cells unharmed. The development of successful immunotherapy requires the identification and characterization of targetable immunogenic tumor antigens. Cancer-testis antigens (CTA) are a group of highly immunogenic tumor-associated proteins that have emerged as potential targets for CD8+ T-cell recognition. In addition to identifying a targetable antigen, it is crucial to understand the tumor immune microenvironment. The level of immune infiltration and mechanisms of immune suppression within the tumor play important roles in the outcome of immunotherapy. The goal of this study is to identify targetable immunogenic antigens for T-cell based immunotherapy and to characterize the tumor immune microenvironment in human dedifferentiated liposarcoma (DDLS) by Nanostring and IHC. To assess the complexity of the human DDLS tumor immune microenvironment and to identify target antigens we used the nCounter NanoString platform to generate a gene expression profile for hundreds of genes from RNA obtained from 29 DDLS and 10 control fat FFPE samples. To classify inflammatory status of DDLS tumors, we performed hierarchical clustering based on expression levels of selected tumor inflammatory signature genes (CCL5, CD27, CD274, CD276, CD8A, CMKLR1, CXCL9, CXCR6, HLA-DQA1, HLA-E, IDO1, LAG3, PDCDILG2, PSMB10, STAT1, TIGIT). To confirm protein expression and distribution of identified antigens, we performed immunohistochemistry on human tissue micro-arrays encompassing DDLPS tumor tissues and matched normal control tissue from 63 patients. IHC for the cancer testis antigens PBK, SPA17, MAGE-A3, NY-ESO-1 and SSX2 was performed, and the staining results were scored by two authors based on maximal staining intensity on a scale of zero to three (absent=0, weak=1, moderate=2, or strong=3) and the percentage of tumor cells that stained. Hierarchical clustering of DDLS tumors based on expression of tumor inflammation signature genes revealed two distinct groups, consisting of 15 inflamed tumor and 14 non-inflamed tumors, demonstrating tumor heterogeneity within the DDLS sarcoma subtype. All antigens were found to be expressed in DDLS at an mRNA level. SPA17 was expressed at the highest levels in DDLS, however, this antigen was expressed at high levels in normal fat. Notably, antigens PBK and TTK had the largest fold change increase in expression in DDLS compared to normal fat controls. Immunohistochemical analysis of selected antigens revealed that PBK was found to be expressed in 96% (52/54) of DDLS samples at high levels. Other antigens were absent or expressed at low levels in DDLS; MAGEA3 in 15.87% (10/63) NY-ESO-1 in 6.35% (4/62) and SSX2 in 12.7% (8/63) and SPA17 in 5.5% (3/54). This data shows considerable inter-tumoral heterogeneity of inflammation, which should be taken into consideration when designing an immunotherapy for DDLS. To date, these results show promising expression of PBK antigen in DDLS, which may be used as a target in the future development of an immunotherapy for sarcoma

Diffuse-type Tenosynovial Giant-Cell Tumour (d-TGCT) of large joints is a rare, locally aggressive, soft tissue tumour affecting predominantly the knee. Previously classified as Pigmented Villonodular Synovitis (PVNS), this monoarticular disease arises from the synovial lining and is more common in younger adults. Given the diffuse and aggressive nature of this tumour, local control is often difficult and recurrence rates are high. Current literature is comprised primarily of small, and a few larger but heterogeneous, observational studies. Both arthroscopic and open synovectomy techniques, or combinations thereof, have been described for the treatment of d-TGCT of the knee. There is, however, no consensus on the best approach to minimize recurrence of d-TGCT of the knee. Some limited evidence would suggest that a staged, open anterior and posterior synovectomy might be of benefit in reducing recurrence. To our knowledge, no case series has specifically looked at the recurrence rate of d-TGCT of the knee following a staged, open, posterior and anterior approach. We hypothesized that this approach may provide better recurrence rates as suggested by larger more heterogeneous series. A retrospective review of the local pathology database was performed to identify all cases of d-TGCT or PVNS of the knee treated surgically at our institution over the past 15 years. All cases were treated by a single fellowship-trained orthopaedic oncology surgeon, using a consistent, staged, open, posterior and anterior approach for synovectomy. All cases were confirmed by histopathology and followed-up with regular repeat MRI to monitor for recurrence. Medical records of these patients were reviewed to extract demographic information, as well as outcomes data, specifically recurrence rate and complications. Any adjuvant treatments or subsequent surgical interventions were noted. Twenty-three patients with a minimum follow-up of two years were identified. Mean age was 36.3 at the time of treatment. There were 10 females and 13 males. Mean follow-up was seven and a half years. Fourteen of 23 (60.9%) had no previous treatment. Five of 23 had a previous arthroscopic synovectomy, one of 23 had a previous combined anterior arthroscopic and posterior open synovectomy, and three of 23 had a previous open synovectomy. Mean time between stages was 87 days (2.9 months). Seven of 23 (30.4%) patients had a recurrence. Of these, three of seven (42.9%) were treated with Imatinib, and four of seven (57.1%) were treated with repeat surgery (three of four arthroscopic and one of four open). Recurrence rates of d-TGCT in the literature vary widely but tend to be high. In our retrospective study, a staged, open, anterior and posterior synovectomy provides recurrence rates that are lower than rates previously reported in the literature. These findings support prior data suggesting this approach may result in better rates of recurrence for this highly recurrent difficult to treat tumour

Diffuse-type Tenosynovial Giant-Cell Tumour (d-TGCT) of large joints is a rare, locally aggressive, soft tissue tumour affecting predominantly the knee. Previously classified as Pigmented Villonodular Synovitis (PVNS), this monoarticular disease arises from the synovial lining and is more common in younger adults. Given the diffuse and aggressive nature of this tumour, local control is often difficult and recurrence rates are high. Current literature is comprised primarily of small, and a few larger but heterogeneous, observational studies. Both arthroscopic and open synovectomy techniques, or combinations thereof, have been described for the treatment of d-TGCT of the knee. There is, however, no consensus on the best approach to minimize recurrence of d-TGCT of the knee. Some limited evidence would suggest that a staged, open anterior and posterior synovectomy might be of benefit in reducing recurrence. To our knowledge, no case series has specifically looked at the recurrence rate of d-TGCT of the knee following a staged, open, posterior and anterior approach. We hypothesized that this approach may provide better recurrence rates as suggested by larger more heterogeneous series. A retrospective review of the local pathology database was performed to identify all cases of d-TGCT or PVNS of the knee treated surgically at our institution over the past 15 years. All cases were treated by a single fellowship-trained orthopaedic oncology surgeon, using a consistent, staged, open, posterior and anterior approach for synovectomy. All cases were confirmed by histopathology and followed-up with regular repeat MRI to monitor for recurrence. Medical records of these patients were reviewed to extract demographic information, as well as outcomes data, specifically recurrence rate and complications. Any adjuvant treatments or subsequent surgical interventions were noted. Twenty-three patients with a minimum follow-up of two years were identified. Mean age was 36.3 at the time of treatment. There were 10 females and 13 males. Mean follow-up was seven and a half years. Fourteen of 23 (60.9%) had no previous treatment. Five of 23 had a previous arthroscopic synovectomy, one of 23 had a previous combined anterior arthroscopic and posterior open synovectomy, and three of 23 had a previous open synovectomy. Mean time between stages was 87 days (2.9 months). Seven of 23 (30.4%) patients had a recurrence. Of these, three of seven (42.9%) were treated with Imatinib, and four of seven (57.1%) were treated with repeat surgery (three of four arthroscopic and one of four open). Recurrence rates of d-TGCT in the literature vary widely but tend to be high. In our retrospective study, a staged, open, anterior and posterior synovectomy provides recurrence rates that are lower than rates previously reported in the literature. These findings support prior data suggesting this approach may result in better rates of recurrence for this highly recurrent difficult to treat tumour

Myxofibrosarcoma (MFS) is the second most common subtype of soft tissue sarcoma (STS) and is associated with a high rate of local recurrence after resection. These tumours frequently present with peri-lesional edema, termed “tumour tails” on staging MRI scans [1]. Tumour tails(TT) may contain satellite neoplastic cells or can represent benign reactive edema. There are no clear radiological features to distinguish malignant from reactive peri-lesional edema which limits accurate surgical planning, resulting in either high rates of inadvertently positive resection margins and local recurrences or overly-aggressive resections which negatively impact function and increase morbidity [2]. The objective of this pilot study was to prospectively study a cohort of MFS patients with TTs in an attempt to identify radiological features that predict which type of edema is malignant and requires resection together with the main tumour mass. Patients diagnosed with MFS on biopsy at an orthopaedic oncology referral centre between January 1-December 31 2018 who also had TTs on staging MRI scans were prospectively recruited for the study. Tumours were treated with wide surgical excision, including the TTs, and (neo)adjuvant radiotherapy as per institutional protocol. Staging MRI scans were reviewed in a blinded fashion by two musculoskeletal radiologists to distinguish malignant from reactive TTs. The main tumour mass underwent standard histological evaluation while the regions encompassing the TTs were photographed and sectioned into grids. Each tissue section was examined histologically for the presence of satellite neoplastic cells based on morphological criteria. Radiological and histological findings were compared. Six patients met the inclusion criteria and underwent analysis. All tumours were located in the extremities and were deep to fascia. Mean age at presentation was 67 years (range 51 – 85), with a male:female ratio of 4:2. All patients received radiotherapy (50 Gy), either pre- (n=4) or post-operatively (n=2) based on multidisciplinary tumor board discussion or enrolment in a prospective clinical trial. Radiologically, TTs were labelled as malignant in four patients (66.7%) and as benign TTs in two others. The tails were recognised to be malignant due to the differing signal characteristics to reactive edema on mixed MRI sequences. The radiological evaluation correlated exactly with histological analysis, as satellite neoplastic cells were identified microscopically in the same four cases in which the TTs were designated to be malignant by MRI (specificity&sensitivity=100%). Surgical resection margins were microscopically positive in 50% of cases in the TTs themselves, and 75% of cases in which TTs were designated as malignant on staging MRI. “The malignant nature of peri-lesional edema in MFS, also known as the TT, was accurately predicted in this small pilot study based on specific radiological features which correlated exactly with histologic identification of isolated tumor cells. These findings validate development of a larger prospective study to recruit additional patients with tumor tails beyond just MFS, in order to more robustly study the correlation between the MRI appearance and histological distribution of satellite sarcoma cells in peri-lesional edema in STS. We are already recruiting to this expanded radiological-histological investigation including evaluation of additional novel MRI sequences

Resection of the proximal femur raises several challenges to the orthopedic oncology surgeon. Among these is the re-establishment of the abductor mechanism that might impacts on hip function. Extent of tumor resection and surgeons’ preferences dictate the reconstruction method of the abductors. While some surgeons advocate the necessity of greater trochanter (GT) preservation whenever possible, others attempt direct soft tissues reattachment to the prosthesis. Sparse data in the literature evaluated the outcomes of greater trochanter fixation to the proximal femur megaprosthesis. This is a retrospective monocentric study. All patients who received a proximal femoral replacement after tumor resection between 2005 and 2021 with a minimum follow-up of three months were included. Patients were divided into two groups: (1) those with preserved GT reattached to the megaprosthesis and (2) those with direct or indirect (tenodesis to fascia lata) abductor muscles reattachment. Both groups were compared for surgical outcomes (dislocation and revision rates) and functional outcomes (Trendelenburg gait, use of walking-assistive device and abductor muscle strength). Additionally patients in group 1 were subdivided into patients who received GT reinsertion using a grip and cables and those who got direct GT reinsertion using suture materials and studied for GT displacement at three, six and 12 months. Time to cable rupture was recorded and analyzed through a survival analysis. Fifty-six patients were included in this study with a mean follow-up of 45 months (3-180). There were 23 patients with reinserted GT (group 1) and 33 patients with soft tissue repair (group 2). Revision rate was comparable between both groups(p=0.23); however, there were more dislocations in group 2 (0/23 vs 6/33; p=0.037). Functional outcomes were comparable, with 78% of patients in group 1 (18/23) and 73% of patients in group 2 (24/33) that displayed a Trendelenburg gait (p=0.76). In group 1, 70% (16/23) used walking aids compared to 79% of group 2 (27/33) (p=0.34). Mean abductor strength reached 2.7 in group 1 compared to 2.3 in group 2 (p=0.06). In group 1, 16 of the 23 patients had GT reinsertion with grip and cables. Median survival of cables for these 16 patients reached 13 months in our series. GT displacement reached a mean of two mm, three mm, and 11 mm respectively at three, six and 12 months of follow-up in patients with grip and cables compared to 12 mm, 24 mm and 26 mm respectively at the same follow-up intervals in patients with GT stand-alone suture reinsertion(p<0.05). Although GT preservation and reinsertion did not improve functional outcomes after proximal femur resection and reconstruction with a megaprosthesis, it was significantly associated with lower dislocation rate despite frequent cable failure and secondary GT migration. No cable or grip revision or removal was recorded. Significantly less displacement was observed in patients for whom GT reattachment used plate and cables rather than sutures only. Therefore we suggest that GT should be preserved and reattached whenever possible and that GT reinsertion benefits from strong materials such as grip and cables

Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging (BLI) and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with increased expression of Runx-2 (p = 0.009), Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in partial osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), and did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing

Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with significantly increased expression of the Osteoblast markers Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), but did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor with an intermediate tendency to metastasize, which is found in many different locations including head and neck, abdomen, chest cavity and extremities. Also, meningeal hemangiopericytoma (HPC) is considered an SFT which arises in the meningeal membranes. SFT family shows an undetermined biologic behavior varying from a silent indolent tumor to an aggressive malignant form; however, benign and malignant variants of SFT may have similar cytopathologic characteristics. In this study, we defined the factors correlated with SFT's aggressive behavior and patient's survival. This is a retrospective study based on medical records of 85 patients who were suffering from SFT and had been treated at McGill University Health Centre (MUHC) between 1984 and 2017. We used multivariate logistic regression analysis to address any association between the variables including patient's demographics, tumor size, primary location of the tumor, pathological features, treatment methods and outcomes. The median of the follow-up period was 60 months. The patient's age or gender had no association with tumor aggressive behavior or patient's survival. Anatomical origin of primary tumor had no strong correlation with the patient's disease related death (DRD); however, tumors originated from CNS showed more aggressive behavior. There was an association between tumor size more than 7 cm and distant metastasis (MT) (p= 0.03) and DRD (p=0.03). The tumor size also correlated with the 5-year disease-free survival (p=0.017). We had three histologic groups: 1- Benign SFT (30 cases), 2- cellular SFT or HPC (29 cases), 3- malignant SFT or anaplastic HPC (26 cases). Although univariate analysis demonstrates that patients suffering from cellular SFT and malignant SFT showed increased aggressive behavior of the tumor, multivariate analysis didn't verify the mentioned association. Patients with positive margins had increased odds ratio to experience tumor local recurrence (LR) (p= 0.05) and LR was correlated with DRD in our patients (p=0.006). Radiotherapy had no statistical association with LR, MT or DRD. Frequency of LR and MT in the study were 25.7% and 29.8% respectively. 5-year disease-free survival in our patients was 76%. The size of SFT is the most correlative predictor of the tumor's aggressive behavior. The local recurrence of SFT is associated with disease related death; therefore, resection of the tumor with negative margins provides the highest chance of cure. In addition, a cellular SFT should be treated like a malignant variant of the tumor

Ewing Sarcoma is the second most common primary bone sarcoma in young patients, however, there remains geographical variation in the treatment of these tumours. All patients receive neoadjuvant chemotherapy and, in most cases, the soft tissue mass diminishes significantly in volume. Controversy surrounds whether to then treat the pre- or post-chemotherapy tumour volume. Many centres advocate either (1) resection of the pre-chemotherapy volume or (2) treatment of the pre-chemotherapy volume with radiation followed by resection of the post-chemotherapy volume. These approaches increase both the short and long-term morbidity for this young patient population. In this study, we retrospectively reviewed our experience resecting only the post-chemotherapy volume without the use of (neo)adjuvant radiotherapy. A retrospective analysis of all patients with Ewing Sarcoma treated at a tertiary orthopaedic oncology centre was conducted. All patients were treated as per the consensus opinion of the multidisciplinary tumour board. Demographic and oncological variables were collected from our institutional database. Presentation and re-staging MRI scans were reviewed to evaluate pre- and post-chemotherapy tumour volumes. Operative and pathology reports were utilized to determine the extent of the surgical resection. Outcome variables included local recurrence free-, metastasis free- and overall survival. Sixty-five patients were identified in our institutional database of which 56 did not receive (neo)adjuvant radiotherapy. Median age at diagnosis was 24 years (range 13–64), 60% of patients were male and 67.6% of tumours were located in the appendicular skeleton. All 56 patients not treated with radiotherapy had resection of the post-chemotherapy tumour volume. There were 3 local recurrences in this group with a mean follow-up of 70.8 months (range 2 to 328). The median overall survival was 47 months and the mean of 70.8months. The rate of local recurrence is comparable to reports in the literature in which patients had their entire pre-chemotherapy tumour volume treated by radiation and/or surgery. Similarly, two-year overall survival for our patient cohort is not significantly different from previous studies in which more aggressive local control measures were employed. Resecting the post-chemotherapy tumour volume in Ewing Sarcoma without the use of (neo)adjuvant radiotherapy does not appear to increase the risk of local recurrence or negatively impact overall survival. This approach should be studied further as it reduces the risk of short and long-term complications for this patient population.”

Osteosarcoma (OS) is the most prevalent bone tumor in children and young adults. Most tumors arise from the metaphysis of the long bones and easily metastasize to the lungs. Current therapeutic strategies of osteosarcoma are routinely surgical resection and chemotherapy, which are limited to the patients suffering from metastatic recurrence. Therefore, to investigate molecular mechanisms that contribute to osteosarcoma progression is very important and may shed light on targeted therapeutic approach to improve the survival of patients with this disease. Several miRNAs have been found expressed differentially in osteosarcoma (OS), In this study, we found that miR-144 significantly suppresses osteosarcoma cell proliferation, migration andinvasion ability in vitro, and inhibited tumor growth and metastasisin vivo. The function and molecular mechanism of miR-144 in Osteosarcoma was further investigated. Tissue samples from fifty-one osteosarcoma patients were obtained from Shanghai Ninth People's Hospital. The in vitro function of miR-144 in Osteosarcoma was investigated by cell viability assay, wound healing assay, invasion assay, the molecular mechanism was identified by Biotin-coupled miRNA capture, Dual-luciferase reporter assays, etc. the in vivo function of miR-144 in osteosarcoma was confirmed by osteosarcoma animal model and miR-144−/− zebrafish model. Mechanically, we demonstrated that Ras homolog family member A (RhoA) and its pivotal downstream effector Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) were both identified as direct targets of miR-144. Moreover, the negative co-relation between downregulated miR-144 and upregulated ROCK1/RhoA was verified both in the osteosarcoma cell lines and clinical patients' specimens. Functionally, RhoA with or without ROCK1 co-overexpression resulted a rescue phenotype on the miR-144 inhibited cell growth, migration and invasion abilities, while individual overexpression of ROCK1 had no statistical significance compared with control in miR-144 transfected SAOS2 and U2-OS cells. This study demonstrates that miR-144 inhibited tumor growth and metastasis in osteosarcoma via dual-suppressing of RhoA and ROCK1, which could be a new therapeutic approach for the treatment ofosteosarcoma

Benign aggressive tumors are common and can be debilitating for patients especially if they are in peri-articular regions or cause pathological fracture as is common for giant cell tumor of bone (GCT). Although GCT rarely metastasize, the literature reports many series with high rates of local recurrence, and evidence about which risk factors influence recurrence is lacking. This study aims to evaluate the recurrence rate and identify local recurrence risk factors by reviewing patient data from a single high-volume orthopedic oncology center. A retrospective analysis of all patients treated for GCT at a tertiary orthopedic oncology center was conducted. In total 413 patients were treated for GCT between 1989 and 2017. Multiple patient and tumour characteristics were analysed to determine if they influenced local recurrence including: age, gender, anatomical site, Campanacci stage, soft tissue extension, presence of metastasis, pathologic fractures, and prior local recurrence. Additional variables that were analysed included type of treatment (en bloc resection or aggressive intralesional curettage) and use of local adjuvants. The main outcome parameters were local recurrence- free survival, metastasis-free survival and complications. Patients treated with Denosumab were excluded from analysis given its recently documented association with high rates of local recurrence. “There were 63/413 local recurrences (15.3%) at a mean follow-up of 30.5 months. The metastatic rate was 2.2% at a mean 50.6 months follow-up and did not vary based on type of treatment. Overall complication rate of 14.3% was not related to treatment modality. Local recurrence was higher (p=0.019) following curettage (55/310; 17.7%) compared to resection (8/103; 7.8%) however, joint salvage was possible in 87% of patients (270/310) in the curettage group. Use of adjuvant therapy including liquid nitrogen, peroxide, phenol, water versus none did not show any effect on local recurrence rates (p= 0.104). Pathological fracture did not affect local recurrence rates regardless of treatment modality (p= 0.260). Local recurrence at presentation was present in 16.3% (58/356) patients and did not show any significance for further local recurrence (p= 0.396). Gender was not associated with local recurrence (p=0.508) but younger patient age, below 20 years (p = 0.047) or below 30 years (p = 0.015) was associated with higher local recurrence rates. GCT in distal radius demonstrated the highest rate of local recurrence at 31.6% compared to other sites, although this was not significant (p=0.098). In addition, Campanacci stage and soft tissue extension were not risk factors for recurrence. The overall GCT local recurrence rate was 15.3%, but varied based on the type of resection: 17.7% following joint sparing curettage compared to 7.8% following resection. Local recurrence was also higher with younger patient age (30 years or less) and in distal radius lesions. In addition, neither Campanacci stage, soft tissue extension or presence of a pathologic fracture affected local recurrence. Most patients with GCT can undergo successful curettage and joint sparing, while only a minority require resection +/− prosthetic reconstruction. Even in the presence of soft tissue extension or a pathologic fracture, most joints can be salvaged with curettage

The use of endoprosthesis implants is frequent for tumours involving the proximal third of the femur and not amenable to primary arthroplasty or internal fixation. In this population, these implants are preferentially cemented given poor bone quality associated with systemic diseases and treatments. Loosening is a common complication of these implants that have been linked to poor bone quality, type of implants and importantly cementing technique. Thus, these techniques vary between different surgeons and based mainly on previous experience. One of the most successful cementing techniques in the arthroplasty literature is the French paradox. This technique involves removing the cancellous bone of the proximal femoral metaphysis and selects the largest stem to tightly fit the created cavity delineated by cortical bone. Cementing the implant results in a very thin cement layer that fills the inconsistent gaps between the metal and the bone. To our knowledge, no previous report exists in the literature assessing loosening in proximal femur replacement using the French paradox cementing technique. In this study, we sought to examine (1) rates of loosening in proximal femur replacement, and (2) the oncological outcomes including tumour recurrence and implant related complications. A retrospective study of 42 patients underwent proximal femur replacement between 1990 and 2018 at our institution. Of these, 30 patients met our inclusion criteria. Two independent reviewers have evaluated the preoperative and the most recent postoperative radiographs using the International Society of Limb Salvage (ISOLS) radiographic scoring system and Gruen classification for femoral stem loosening. Additionally, the acetabulum was evaluated for erosion according to the criteria of Baker et al. The mean age of this cohort was 60.5 (19–80), with 60% being males. The primary origin was metastatic in 17 (56.7%) patients, bone sarcoma in 10 (33.3%) patients and soft tissue sarcoma in 3 (10%) patients. Pathological fractures were present in 11 (36.7%) patients. Seven (23.3%) patients had prior intramedullary nailing. Preoperative radiotherapy was used in 8 (26.7%) and postoperative radiotherapy in 17 (56.7%) patients. The mean clinical follow-up was 25.2±26.3 months and the mean radiographical follow-up was 24.8±26 months. The mean ISOLS score for both reviewers was found to be 89±6.5% and 86.5±6.1%, respectively. Additionally, the first reviewer found two patients to be possibly loos (6.7%) compared to one (3.3%) patient for the second reviewer. No components scored as probably or definitely loose and non-required revision for either loosening or metal failure. Furthermore, both reviewers showed no acetabular erosion in 25 (83.3%) and 24 (80%) patients, respectively. On the other hand, the overall rate of complications was 36.6% with 11 complications reported in 30 patients. Local recurrence occurred in five (16.6%) patients. Prosthetic Dislocation was the most frequent complications with eight dislocations in four patients. Despite complications, our results showed no radiographic evidence of stem loosening. Cementing proximal femur prosthesis with a tight canal fit and with a thin cement mantle appears to be a viable option at short and medium term

The appearance of a tumor as a result of chronic osteomyelitis is a relatively rare complication and of late-onset, with a low frequence in the modern world. For the majority of patients, the interval between the onset of primitive osteomyelitis and malignant degeneration is of several decades. We present our cases and the protocol of treatment used. From January 1977 to December 2014 we treated 36 patients (33M, 3F) suffering from squamous cell tumor out of a series of 247 tibial and 74 calcaneal osteomyelitis. 26 patients had chronic osteomyelitis of tibia, 10 of the calcaneus. Based on the functional needs of patients after resection of the tumor, in 18 we applied the Ilizarov apparatus, in 14 we opted for a two steps surgery, with the help of plastic surgeon; four required amputation. 29 patients healed. After 2-years of follow up 3 patients underwent to an amputation in the proximal third of the leg, 4 had a local recurrence. All patients were assessed by SF32 and the QoL test. Squamous cell tumor is the most common malignant tumor in chronic osteomyelitis. For the diagnosis of malignant transformation from a chronic ulcer there is a thorough process. Serial biposies must be performed, especially with the emergence of new clinical signs (increased pain, a bad smell, and changes in secretion by the wound). The definitive treatment is often amputation proximal to the tumor or wide local excision in combination with adjuvant chemotherapy and radiotherapy in selected patients. Early detection can sometimes allow limb salvage. However, the most effective treatment is prevention with the definitive treatment of osteomyelitis, including appropriate debridement, wide excision of the affected area, and early reconstruction

Aim. Periprosthetic joint infections are a devastating complication after modular endoprosthetic reconstruction following resection of a musculoskeletal tumour. Due to long operating times, soft tissue dissection and immunosuppression, the infection rate after limb salvage is high and ranges between 8% and 15%. The aim of this retrospective single centre study was to assess the reinfection and re-reinfection rate after septic complications of megaprostheses. Method. In this retrospective study, 627 patients with a primary replacement of a musculoskeletal tumour of the lower limb and reconstruction by a megaprosthesis were recorded from 1983 – 2016. 83 out of 621 patients available for follow-up experienced an infection (13.4%). Two patients were treated with debridement and removal of the mobile parts, 61 patients with a one-stage revision, 16 patients with a two-stage revision, and 4 patients with an amputation. The mean follow up was 133 months (range: 2 – 423 months). Results. The reinfection rates after debridement, one-stage revision, two-stage revision, and amputation were 100% (CI 95%: 20 −100%), 49% (CI 95%: 36 – 62%), 38% (CI 95%: 6 – 76%), and 0%, respectively. A reinfection occurred after a mean of 38,7 months (range: 0 to 201 months). The most commonly isolated microorganisms were coagulase negative Staphylococci, followed by Staphylococcus aureus. A re-reinfection occurred in 100% after debridement, in 44% (CI 95%: 22 – 69%) after one-stage revision, in 55% (CI 95%: 31 – 91%) after two-stage revision, and 0% after amputation. Regarding two-stage revision, there was a statistically significant difference in infection rates between patients treated with complete removal of the megaprosthesis and patients with at least one retained component (Fisher's exact test, p = 0.027). Conclusions. Septic failures after megaprosthesis reconstruction of a musculoskeletal tumour of the lower limb are difficult to treat and show high reinfection and re-reinfection rates. A two-stage revision with removal of all components showed the best results among limb salvage procedures for periprosthetic megaprosthesis infection

Limb salvage in musculoskeletal tumor surgery may be complicated by infection. With the advent of modern techniques and medical management limb sparing surgeries can be considered as an alternative to ablation. Between 1992 and 2014, 17 patients were treated for infected megaprostheses after being surgically treated for musculoskeletal tumors. There were nine females and eight males. The mean time from the index procedure until infection was 30 months. Following radical debridement, the resultant skeletal defect averaged 30 cm. Patients were treated with local antibiotics in polymethyl methacrylate (PMMA) spacers and endoprostheses as well as IV antibiotics for a minimum of six weeks followed by oral antibiotics for an additional six weeks. The initial tumor procedure involved the femur in eleven patients, the tibia in two, the acetabulum in one, the humerus in two, and the ulna in one. Patients had repeat cultures before two-stage reimplantation when their WBC, ESR, and CRP returned to normal. Patients were reimplanted when final cultures were negative. Thirteen patients were treated using a two-stage protocol with customized intraoperative antibiotic impregnated PMMA spacers including intramedullary nails for a mean of 10 months and the other four patients had a one-stage procedure. These four patients included two patients with a total femur replacement and two patients with an allograft-prosthetic composite of the proximal humerus and ulna. The organisms cultured were gram positive in 14 cases, mixed gram positive and negative in one case, and two patients had no growth on cultures but histologic evidence of acute infection. Reimplantation was successful in 13 patients after the initial procedure (76%). Four patients had recurrent infections. One of these patients was successfully reimplanted after a one-stage procedure, two had a second two-stage procedure and have retained their spacers, and one had an amputation. Successful limb salvage in regards to infection control occurred in 14/17 patients (82%). One additional patient required an amputation for an oncologic complication (local recurrence), so the overall limb salvage rate was 13/17 (76%). Patients with megaprosthetic infections following limb salvage treatment for musculoskeletal tumors do not have to be uniformly subject to amputation. Radical debridement and appropriate antibiotics in conjunction with custom spacers followed by selective one- and two-stage reimplantation results in successful limb salvage in 82% of patients. This result is similar to other reports despite the large size average defects

We performed a retrospective review of 98 patients with malignant tumours of the periacetabular region, treated by resection and endoprosthetic reconstruction between 1971 and 2005 at the Royal National Orthopaedic Hospital, Stanmore and The Royal Orthopaedic Hospital, Birmingham. The mean age of the patients was 43.6 years (10 to 76). 53 patients (54%) were male. The age distribution demonstrated peaks in the 2nd and 6th decades. The mean follow up was 65 months (2 to 405. The overall 10-year survival rate was 56% (determined by the Kaplan-Meier method). 54 patients (58.1%) had one or more complications. Infection was the most common (30%) with the majority occurring in the first 2 years. Dislocation occurred in 19 (20%) of our patients all in the first year following surgery. All were recurrent with a mean of 2.9 (2 to 6) episodes. Operations performed before 1994 were associated with a dislocation rate of 40.5% and after 1996 the rate was only 3.9% (p < 0.001). Function was assessed according the Toronto Extremity Salvage Sore (TESS). The overall TESS was 59.4. In patients that had a major complication the TESS was 37.1 but in the group that did not the TESS was 70.3 (p < 0.001). Men experienced higher rates of death, infection and revision than women (p < 0.05). The local recurrence rate was 31% with high grade tumours associated with higher recurrence rates (p < 0.05). Tumour resection in the ilium is associated with higher rates of infection than tumours located in the periacetabular region alone (p < 0.05). This method of reconstruction is still associated with high complication rates. Function is good if a major complication can be avoided. The lower dislocation rate more recently is probably the result of improved surgical technique and the use of larger femoral heads

Introduction. Bony tumours of the foot account for approximately 3% of all osseous tumours. However, literature regarding os calcis and talar tumours comprises individual case reports, short case series or literature reviews with no recent large series. Methods. We retrospectively reviewed the medical notes and imaging for all patients with calcaneal or talar tumours recorded in the Scottish Bone Tumour Registry since the 1940's. Demographics, presentation, investigation, histology, management and outcome were reviewed. Results. 34 calcaneal tumours and 23 talar tumours were identified. Calcaneal tumours. 2:1 male prevalence, mean age at presentation 30, average length of symptoms 9 months. 4 cases presented with pathological fracture. 21 benign tumours including 6 unicameral bone cysts, 3 chondroblastoma, and a wide variety of individual lesions. 13 malignant tumours comprising 6 osteosarcoma, 5 chondrosarcoma and 2 Ewings sarcoma. Talar Tumours. male to female ratio 3:1, mean age at presentation 28, average length of symptoms 5 months. 20 benign cases including 7 osteoid osteoma, 4 chondroblastoma, and several individual lesions. 3 malignant lesions comprising 2 chondrosarcoma, 1 osteosarcoma. Discussion. Tumours of the hindfoot frequently are delayed in diagnosis due to their rarity and lack of clinician familiarity. They are more common in men, especially talar tumours, which are most commonly benign osteoid osteoma or chondroblastoma. Calcaneal tumours have 1 in 3 risk of malignancy and cover a wider variety of lesions. Osteosarcoma of the foot tends to present later than other anatomical regions. Outcome is dependant on early diagnosis, timely surgery and most importantly neo-adjuvant chemotherapy. Diagnosis is often made on plain radiograph but MRI is the gold standard. Despite their rarity clinicians should maintain a high index of suspicion as accurate and timely diagnosis is important to management and outcome

Introduction. Three-dimensional preoperative planning and bone tumour resection by navigation have been used in the past ten years. According to literature this workflow increases the surgical “accuracy”. However, there are a few and not completely clear reports describing accuracy in preoperative planning and navigation. The objective of this preliminary study was to determine the accuracy of osteotomies planned and guided by navigation in pelvis tumour resection. We assume that the surgical specimen scanned and 3D reconstructed is an acceptable method to determine the accuracy qualitatively and quantitatively of a virtual planning and navigation surgical workflow. Materials and Methods. A total of four patients were evaluated between May 2010 and February 2011, age range: 6–38, 17.4 mean; 2 males and 2 females. There were 4 malignant tumours: Malignant Schwannoma (1), Ewing's tumor (1) and Chondrosarcoma (2). All anatomic regions compromised by the tumour were preoperatively CT scanned (Mutislice 64, Aquilion, Toshiba Medical Systems, Otawara, Japan). Magnetic resonance images (MRI) of the corresponding region were acquired using a 1.5-T unit (Magnetom Avanto, Siemens Medical Solutions, Erlangen, Germany). Image fusion was applied to CT and MRI studies in order to determine the bone cortex and the intra-extraosseous soft tissues tumour extension. Once the fusion was obtained osteotomies were planned, taking into account the tumour extension in a three-dimensional virtual scenario. All patients were planned for two uniplanar osteotomies (intercalary resection). The minimal margin was determined in each plane by measuring the closest distance between malignant tumour and osteotomy plane. These studies allowed the visualisation of the tumour and the application of a virtual osteotomy. The simulation was carried out by using a computer-aided design (CAD) software, Mimics (Materialise, Leuven, Belgium). Three-dimensional preoperative planning was obtained in CAD format. Next, 3D models were exported to CT data sets in Digital Imaging and Communications in Medicine (DICOM) format and uploaded to the navigation system (3D OrthoMap navigation software v1.0, Stryker Navigator, Freiburg, Germany). Using the standard navigation tools (navigated pointer, camera and infrared tracker devices applied to the patient) the surgeon was able to establish a correspondence in a computer monitor between 3D images and real bone. Once osteotomies were performed, the tumour surgical specimen obtained was CT scanned and 3D reconstructed similarly to what was done previously to surgery to CT images acquired with the preoperative protocol in patients. Results. The correlation between the osteotomies preoperatively planned and the osteotomies achieved by navigation was in a global mean of 0.73 millimeters (SD: 3.14) in a total of 6 planes evaluated. Conclusion. According to clinical relevance, this work shows an acceptable accuracy in preoperative planning and navigation. Furthermore, we demonstrate the usefulness of three-dimensional models of surgical specimens when surgeons need to determine quantitative and qualitative accuracy of 3D planning and navigation procedures

Biological reconstruction techniques after diaphyseal tumour resection have increased in popularity in recent years. High complication and failure rates have been reported with intercalary allografts, with recent studies questioning their role in limb-salvage surgery. We developed a technique in which large segment allografts are augmented with intramedullary cement and fixed using compression plating. The goal of this study was to evaluate the survivorship, complications and functional outcomes of these intercalary reconstructions. Forty-two patients who had reconstruction with an intercalary allograft following tumour resection between 1989 and 2010 were identified from our prospectively collected database. Allograft survival, local recurrence-free, disease-free and overall survival were assessed using the Kaplan-Meier method. Patient function was assessed using the Musculoskeletal Tumour Society (MSTS) scoring system and the Toronto Extremity Salvage Score (TESS). The 23 women and 19 men had a mean age of 33 years (14–77). The most common diagnoses were osteosarcoma (n=16) and chondrosarcoma (n=9). There were 9 humerus, 18 femur and 15 tibia reconstructions. At a mean follow-up of 95 months (5–288), 31 patients were alive without disease, 10 were dead of disease and 1 was deceased of other causes. There were 4 local recurrences and 11 patients developed metastatic disease. 5-year local recurrence free survival was 92%, 5-year disease-free survival was 70% and overall survival was 75%. Fourteen of 42 patients (33%) experienced complications: 5 wound healing complications, 4 infections, 2 non-unions, 2 fractures and 1 nerve palsy. Four allografts (9.5%) were revised for complications and 2 (5%) for local recurrence. Mean allograft survival was 85 months (4–288). Mean time to union was 8.2 (3–36) months for the proximal osteotomy site and 8.1 (3–23) months for the distal osteotomy site. The mean score for MSTS 87 was 29.4 (+/− 4.4), MSTS 93 was 83.7 (+/−14.8) and TESS was 81.6 (+/−16.9). An intercalary allograft augmented with intramedullary cement and compression plate fixation provides a reliable and durable method of reconstruction after tumour resection. Complication rates are comparable to the literature and are associated with high levels of patient function and satisfaction

Background. Revision THA presents significant challenges for the surgeon when the proximal femur is deficient or mechanically unreliable. The aim of this study is to assess the clinical and functional results of the use of tumor enndoprosthesis to reconstruct the proximal femur when there is massive bone loss. Patients and Methods. A prospective study was conducted involving 10 cases. The follow up of the cases ranged from 12 months to 30 months with a mean period of an average of 23months. The indications for revision surgery were aseptic loosening in 9 cases and septic loosening in one case Harris hip score was used for pre and postoperative clinical evaluation of the patients. Results. At the latest follow up the Harris Hip scores improved from a preoperative average of 16 (range, 3-47), to a postoperative average of 75.6 (range, 66-94). The complications that we encountered in the study included one case of superficial wound infection, another case developed sciatic nerve palsy postoperatively. No other complications were reported. Conclusion. Revision hip replacement in proximally compromised femurs presents a significant surgical challenge. When there is massive proximal femoral bone loss proximal fitting revision stems do not achieve adequate fixation hence the use of tumor prosthesis is indicated