Objective: To determine patient characteristics and outcomes for extremity rhabdomyosarcoma (RMS) utilizing an international cohort of prospectively treated patients.

Methods: Data were collected from 566 patients (1984 through 2003) treated on cooperative protocols : US IRS III, IV Pilot, IV studies – SIOP 84, 89, 95 studies – Italian ICG 79, 88, 96 studies – German CWS81, 86, 91, 96 studies.

Results: 29 % of the patients were < 3 year old, 36 % were 3 to 10 year old and 35 % > 10 year old. 350 (63%) patients had alveolar RMS and 116 (22%) had regional nodes.

The overall survival and EFS were 65% and 51% at 5 years respectively and 59% and 48% at 10 years respectively.

By univariate analysis, EFS was influenced by age below 3 years but not by age over 10 years (EFS were 61%, 49% and 46% for patients below 3 years, from 3 to 10 and 10 years or more respectively). It was also influenced by tumor invasiveness, tumor size, lymph node involvement, histology, completeness of surgery at diagnosis and cooperative groups. In multivariate analysis of EFS, size, lymph nodes, quality of surgery, cooperative groups had independent impact. Age and histology had no more impact.

OS (univariate analysis) was influenced by age below 3 years but not by age over 10 years (OS were 77%, 61% and 58% for patients below 3 years, from 3 to 10 and 10 years or more respectively). In multivariate analysis, age, lymph nodes, tumour invasiveness, quality of surgery at diagnosis had independent impact. Histology, tumour size and cooperative groups had no more impact.

Conclusion: This analysis shows that significant cut-point for age is 3 years, that histology per se has no impact on OS and EFS. It also underscores the impact of initial surgery on outcome.