Rhabdomyosarcoma in adults: analysis of treatment modalities in a prospective single-center series.

Rhabdomyosarcoma (RMS) is rare in adults and it is generally characterized by poor outcome. In a previous retrospective study, we demonstrated a better prognosis in adults treated with multimodality approach resembling pediatric protocols. Thereafter, we developed specific recommendations based on the principles adopted in pediatric oncology. The present analysis reports the results in a subsequent prospective series. The study included 95 consecutive patients (age 18-77 years) treated from 2002 to 2015 for embryonal and alveolar RMS. As in the previous series, patients were stratified by the appropriateness of their treatment according to therapeutic guidelines for childhood RMS. The 5-year event-free survival (EFS) and overall survival (OS) rates were 33.6% and 40.3%, respectively. The 5-year EFS was 40.8% for patients with the highest treatment score, and 15% for those with lower score, while OS was 44.4% and 24.5%, respectively. The developing of specific recommendations enabled an increase in the number of patients treated with intensive multimodal treatment resembling pediatric strategy (69.7% vs. 39.1% in the retrospective series). This study reinforced the idea that adherence to the principles of pediatric protocols, improves adult RMS outcomes. However, treating adults with pediatric-type strategy is not enough to achieve the results obtained in children. Issues in compliance and a more aggressive biology of adult RMS might have a role in the different outcome according to age. Improving the collaboration between pediatric and adult oncologists in promoting specific clinical and biological research is crucial to improve the outcome for this patient population.