Comparison of outcomes based on treatment algorithms for rhabdomyosarcoma of the bladder/prostate: Combined results from the Children's Oncology Group, German Cooperative Soft Tissue Sarcoma Study, Italian Cooperative Group, and International Society of Pediatric Oncology Malignant Mesenchymal Tumors Committee

The purpose of this study was to determine patient characteristics and outcomes for bladder/prostate (BP) rhabdomyosarcoma (RMS) using an international cohort of prospectively treated patients comparing different treatment algorithms. Data were collected from 379 patients (1979–1998) treated on protocol; Intergroup Rhabdomyosarcoma Study, IRS‐IV (n = 239 patients), International Society of Pediatric Oncology Malignant Mesenchymal Tumors (MMT) Committee MMT‐84 and ‐89 (n = 74), Italian Cooperative Group, RMS‐79 and RMS‐88 Studies (n = 37) or German Cooperative Soft Tissue Sarcoma Study CWS‐91 protocols (n = 29). A total of 322 (85%) patients had localized embryonal RMS (ERMS) and 27 had metastatic disease. Thirty patients (21 local disease; 9 metastatic) had nonembryonal BP RMS. Patients with localized ERMS had large tumors (64% >5 cm) that were invasive (54%) with uninvolved regional lymph nodes (N0, 93%). The 5‐year failure‐free survival (FFS) was 75% and the overall survival (OS) was 84%, with 89% of deaths attributed to disease. Treatment failures were usually local disease recurrence (60%). Predictors of FFS included T‐stage (invasiveness), size, and histology. FFS was decreased for patients not receiving initial radiotherapy but this did not translate into a decreased OS. The 21 patients with localized nonembryonal BP RMS had a FFS and OS of 47%. The 36 patients with metastatic disease were more likely to be older and had large tumors that were invasive with alveolar histology and regional lymph node involvement. The 5‐year FFS and OS were 41 and 44%, respectively. In conclusion, the majority of BP RMS patients had localized ERMS with a resultant good prognosis using current treatment algorithms. There were differences in FFS between treatment protocols but this did not result in an altered OS.