What comprises appropriate therapy for children/adolescents with rhabdomyosarcoma arising in the abdominal wall? A report from the Intergroup Rhabdomyosarcoma Study Group

Purpose: The aim of this study was to define clinical features and determine the best therapy for patients with rhabdomyosarcoma (RMS) of the abdominal wall. Methods: We examined the demographic, clinical features, therapy (especially surgical), and outcome of 34 patients. Patients received combination chemotherapy after complete surgical resection (group 1, n = 14; 41%); resection with microscopic residual followed by local irradiation (RT; group II, n = 8; 24%); partial resection or biopsy only plus RT with gross locoregional residual tumor (group III, n = 4; 12%); or biopsy only plus RT with metastatic disease (group IV, n = 8; 24%). Patients with group I or group II tumors had undergone partial abdominal wall resection (ie, involved muscle only with preservation of peritoneum, n = 11) or complete abdominal wall resection (n = 7). Four additional patients had groin lesions. Results: Thirty-four children or adolescents with abdominal wall RMS (about 1% of all patients) were treated on Intergroup Rhabdomyosarcoma Study I (IRS-I) through IRS-IV. Overall, adolescents comprised 14 of 34 eligible patients (41%), and 10 of 14 (71%) adolescents had alveolar or undifferentiated tumors versus 8 of 20 (40%) younger children (P = .07). Failure-free survival (FFS) rate and survival rate at 5 years was 65%. Treatment outcome was poorer for patients with group III-IV tumors (P= .01), adolescents (P = .09) and patients with alveolar or undifferentiated sarcomas (P = .12). Conclusion: Patients with localized tumors appear to fare better if they undergo complete abdominal wall resection (long-term survival rate, 100%) versus partial resection (long-term survival rate, 62% [P = .12]).