Current status of treatment for pediatric rhabdomyosarcoma in the USA and Japan.

This article reviews the current status of treatment for children with rhabdomyosarcoma, according to the four risk groups. Low-risk subgroup A: the Children's Oncology Group in the USA recently performed a clinical trial consisting of a chemotherapy regimen with a shortened treatment period and a reduced drug dosage. Patients in this group received only four cycles of vincristine and actinomycin D (VA) after four cycles of vincristine, actinomycin D, and cyclophosphamide (VAC) with cyclophosphamide (CPM) 1.2 g/m(2) and their outcome was no worse than that obtained with previous regimens. Low-risk subgroup B: although marked improvement in survival was seen with an intensive VAC regimen with CPM 2.2 g/m(2) /cycle (Intergroup Rhabdomyosarcoma Study [IRS]-V, 1997-2004), the total dose of CPM in this regimen caused serious and fatal hepatic veno-occlusive disease during treatment and probably cannot avoid infertility or possible secondary cancer as a late effect. Thereafter, a reduced-dose regimen consisting of four cycles of VAC with CPM 1.2 g/m(2) followed by 12 cycles of VA was investigated in the next study, but the outcome appeared to be worse than in IRS-V. Intermediate-risk group: no significant difference was found between VAC/vincristine, topotecan and cyclophispahamide (VTC) and intensive VAC in IRS-V. The results of a subsequent regimen of VAC with CPM 1.2 g/m(2) alternating with vincristine and irinotecan are awaited. High-risk group: overall survival is approximately 30% and has not improved over the last 25 years. Although 18 month failure-free survival (FFS) was improved with an intensive combination therapy regimen, 36 month FFS dropped to 32% and thus better novel approaches or additive treatments are needed.