Embryonal Rhabdomyosarcoma With Metastases Confined to the Lungs: Report From the CWS Study Group

Background. Embryonal rhabdomyosarcoma [RME] is the most common pediatric soft tissue sarcoma. Whereas the prognosis of localized rhabdomyosarcoma has improved, it remains poor for metastatic disease. Methods. We analyzed RME-patients with isolated pulmonary metastases [PRME] treated in four consecutive CWS-trials. Treatment included multiagent chemotherapy and local treatment of the primary tumor. Therapy of lung metastases after induction chemotherapy depended on response and individual decisions. Results. Twenty-nine patients < 21 years had PRME. Their median age was six years, the median follow-up nine years. Twenty-eight children had their primary tumor located in an unfavorable site and 22 of the primaries were > 5 cm. In addition to conventional chemotherapy, seven patients received high-dose treatment and eight patients oral metronomic chemotherapy. The lung metastases were in remission after induction chemotherapy in 22 individuals. 19 patients received no local treatment of metastases; 3 patients had pulmonary metastasectomy and lung radiation was administered to 9 individuals. In total, 24/29 patients achieved a complete remission [CR]. Actuarial 5-year event-free and overall survival for all patients was 37.9 +/- 18% and 48.7 +/- 18%, respectively; it was 45.8 +/- 20% and 58.3 +/- 20% for the 24 patients who achieved a CR. Local treatment of metastases had no impact on the failure pattern. Younger age, good response, achievement of CR and maintenance-treatment were favorable prognostic factors in univariate analysis. Conclusions. Children with PRME have a fair prognosis. Local treatment of metastases did not improve outcome in our sample. Metronomic treatment may be an attractive option for PREM-patients. [correction made here after initial online publication]. Pediatr Blood Cancer 2011;56:725-732. (c) 2010 Wiley-Liss, Inc.