Late events occurring five years or more after successful therapy for childhood rhabdomyosarcoma: a report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group.

The aim of our study was to describe late failures in children who initially survived event-free five years from a diagnosis of rhabdomyosarcoma. Charts of children enrolled in the Intergroup Rhabdomyosarcoma Study Group (IRSG) trials III, IV pilot and IV (1984-1997) who survived five years event-free and subsequently experienced an adverse event (disease recurrence, second malignant neoplasm or death from other causes) were reviewed. Of the 2534 enrolled patients, 1160 were event-free at five years and 48 subsequently experienced a late event. The estimated 10-year event rate for the 1160 patients who were alive and event-free at five years was 9% (95% Confidence Interval (CI) 5%, 13%). Patients with both advanced disease (Group III/IV) and large primary tumours at diagnosis (> 5 cm) were at the highest risk for late events (19%; 95% CI 8%, 30%). Late events after successful treatment for rhabdomyosarcoma occur in 9%. Those with advanced disease and large primary tumours have the highest risk of late events.