High-dose chemotherapy with blood or bone marrow transplants for rhabdomyosarcoma

Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children, is cured with conventional therapy in 70%. However, the 5-year survival for those who relapse is about 30%, and drops to about 15% for those with unfavorable histologies (alveolar/undifferentiated subtypes). We describe outcomes of 62 subjects receiving autologous blood/bone marrow (BM) transplants for RMS between 1989 and 2003, and reported to the Center for International Blood and Marrow Transplantation Research (CIBMTR). Histologic subtype was confirmed by reviewing pathology reports. Treatment-related mortality (TRM), progression-free survival (PFS), and overall survival (OS) were evaluated. Overall, 73% of subjects were <20 years; 39% had cancer bulk >5 cm, 63% had metastasis at diagnosis, 55% had unfavorable histologies, 92% had cancer responsive to chemotherapy pretransplant, and 67% were in first remission. The 1-year TRM was 5% (95% confidence interval [CI], 1%-12%) and the 5-year PFS and OS were 29% (95% CI, 18%-41%) and 32% (95% CI, 21%-44%), respectively. There was only a 4% relapse rate after the first year. There were no differences in 5-year PFS or survival based on histological subtype, transplant in first remission versus relapse (36% versus 29%; P = .5), or transplantation for poor-risk histologies in first remission versus relapse (34% versus 33%; P = .9). Our data indicate that autotransplants for RMS disease are typically done in patients with disease responsive to chemotherapy pretransplant, with approximately one-third long-term survivors. Despite high-risk factors, we also found a low TRM, perhaps reflecting the migration from marrow to blood stem cells as the graft source. Even when performed after relapse for alveolar/undifferentiated histologies, long-term survivals were seen seemingly better than results with conventional therapies.