Local therapy for rhabdomyosarcoma of the bladder and/or prostate without nodal or metastatic spread during the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS2005 study

Background: During the EpSSG RMS2005 trial, organ-sparing surgery (OSS) with brachytherapy (BT) became the local therapy (LT) of choice for selected patients with bladder-prostate rhabdomyosarcoma (BP-RMS). We compare this LT technique with surgical resection and/or external-beam radiotherapy. Methods: Patients with BP-RMS without nodal or metastatic spread enrolled in RMS2005 were categorized by their LT, differentiating OSS from organ-depleting surgery (ODS) and BT from external-beam radiotherapy (EBRT). Progressive disease, relapse or death were considered events for progression-free survival (PFS) and all deaths for overall survival (OS). Results: The cohort comprised 176 patients, aged 10days-21.8years (median 2.5years). Median follow-up was 6.5years (22months-12.5years): 5year-PFS was 80.3 % (95 %CI:73.6–85.5 %); 5year-OS was 90.7 % (95 %CI:85.3–94.2 %). Patients selected for surgery alone or BT with/without OSS (BT+/-OSS) differed significantly in age, tumour size and location from those offered EBRT alone or any other surgery and radiotherapy. Nevertheless, 5year-PFS was similar for the LT groups. However, 5year-OS differed significantly, being highest in patients suitable for surgery alone (100 %; by ODS in 55 %) or BT+ /-OSS (98.1 %; 95 %CI:87.4–99.7 %). Patients with local tumour progression/relapse after EBRT failed salvage: 5year-OS was 81.8 % (95 %CI:58.5–92.8 %) for EBRT alone and 85.3 % (95 %CI:71.6–92.7 %) for surgery and radiotherapy. Postponing LT until after chemotherapy cycle 7 did not significantly impact 5year-PFS or OS. Conclusions: The risk of events was similar for different LT modalities; poor salvage after EBRT significantly reduced 5year-OS. Although not feasible for all, BT+ /-OSS offers an excellent prospect of cure, the best chance of organ retention while avoiding EBRT, and may be delayed for chemotherapy responsive tumours.