High-dose chemotherapy followed by peripheral blood stem cell rescue for metastatic rhabdomyosarcoma: The experience at Chicago Children's Memorial Hospital

Background. Because outcome for metastatic rhabdomyosarcoma remains poor with standard therapy, and because some patients with extensive unresectable metastatic rhabdomyosarcoma are unable to tolerate standard therapy with the associated large radiation fields, peripheral blood stem cell rescue (PB- SCR) following high-dose chemotherapy was offered as consolidative therapy for patients with Stage 4/Group IV rhabdomyosarcoma. Patients and Methods. Eight patients with Stage 4/Group IV rhabdomyosarcoma were diagnosed from May, 1992, through November, 1994. Consolidative PBSCR following thiotepa 300 mg/M² on days -7, -6, and -5; cyclophosphamide 1,500 mg/M² on days -5, -4, -3, and -2; and carboplatin 600 mg/M² on days -3 and -2 was offered to those patients who achieved a complete remission with multimodality therapy. Patients with extensive metastatic disease who did not receive full doses of radiation to all sites of disease remained eligible for high-dose chemotherapy and PBSCR. Results. Five of eight patients achieved a complete response. Four patients underwent PBSCR. One of the four patients is alive without evidence of disease 53 months post-PBSCR. All other patients died of progressive disease. Conclusions. These results, along with the existing literature, show no advantage of high-dose chemotherapy followed by PBSCR as consolidative therapy for patients with Stage 4/Group IV rhabdomyosarcoma over standard dose chemotherapy, radiation, and surgery. For patients with extensive, unresectable disease at diagnosis who cannot receive radiation to all areas of disease based on concerns of marrow reserve, high-dose chemotherapy followed by PBSCR does not appear to provide adequate local control and cannot be offered as curative therapy.