RESUMO
BACKGROUND: To prepare for a Japanese nationwide group study of patients with rhabdomyosarcoma (RMS), we examined the characteristics and outcomes of RMS patients treated recently in Japan. METHODS: We classified 331 RMS patients treated between 1991 and 2002 at 63 institutions according to the Intergroup Rhabdomyosarcoma Study V (IRS-V) risk-group classification. RESULTS: Ten-year survival rates were 86.3% for patients in low-risk subgroup A, 80.7% for low-risk subgroup B, 62.7% for intermediate-risk subgroup A, 61.7% for intermediate-risk subgroup B, and 38.1% for the high-risk group. The outcomes of the patients in the former three groups were 8%, 12%, and 21% worse than the outcomes of the respective patients in the IRS-III and early IRS-IV data. The frequency of the alveolar histological subtype was 21.8%. Chimera genes, which are useful markers for the alveolar subtype, had been examined in only 10% of the patients treated in the period of this investigation. The survival rates of our patients with embryonal and alveolar histological subtypes (65.9% and 63.4%, respectively) were not significantly different. Among the patients in the high-risk group, the 5-year survival of patients who received high-dose chemotherapy (HDC; 58.2%) was significantly better than that of patients who did not receive HDC (18.4%). CONCLUSION: Patients in the lower-risk groups with embryonal-type tumors had poorer outcomes in this retrospective study. The better outcome of patients in the high-risk group is apparently due to the outstanding results obtained with an HDC regimen in a single institution. These results suggest that there is a need for: (1) a standard therapy, (2) a rapid central pathology review including a chimera gene analysis for the lower-risk group, and (3) evaluation of the efficacy of the high-dose regimen for the high-risk group in Japan.
