Treatment of children with nonmetastatic paratesticular rhabdomyosarcoma: results of the Malignant Mesenchymal Tumors studies (MMT 84 and MMT 89) of the International Society of Pediatric Oncology

Abstract

Purpose: To report the results of the Malignant Mesenchymal Tumors studies (MMT 84 and 89) of the International Society of Pediatric Oncology (SIOP) in males with nonmetastatic paratesticular rhabdomyosarcoma.

Patients and methods: From 1984 to 1994, 96 males were treated in SIOP protocols. Radical inguinal orchidectomy was recommended, but initial retroperitoneal lymph node dissection was not performed. Disease was staged according to the SIOP tumor-node-metastasis staging system. Treatment was stratified by stage. In the MMT 89 study, males with completely resected tumors at diagnosis received less chemotherapy (vincristine and dactinomycin) than patients in the MMT 84 study (ifosfamide, vincristine, and dactinomycin).

Results: Median age at diagnosis was 65 months. Thirty-one tumors were larger than 5 cm, and 13 males were older than 10 years with a tumor larger than 5 cm. At a median follow-up of 7 years, 87 patients were alive; 79 were in first complete remission and eight were in second complete remission. Relapse occurred in 16 patients (17%). At 5 years, the overall survival (OS) rate was 92%, with an event-free survival (EFS) rate of 82%. OS and EFS were significantly worse for males with tumors greater than 5 cm and for males older than 10 years at diagnosis.

Conclusion: Males with paratesticular RMS have an excellent prognosis except for a selected group of patients older than 10 years or with tumor greater than 5 cm. Intensified chemotherapy incorporating alkylating agents for this subgroup may be preferred to the use of systematic lymphadenectomy to improve survival while minimizing the burden of therapy.