High-dose carboplatin, etoposide, and cyclophosphamide for patients with refractory germ cell tumors: treatment results and prognostic factors for survival and toxicity.

ABSTRACT

PURPOSE: The efficacy and toxicity of high-dose carboplatin, etoposide, and cyclophosphamide with autologous bone marrow transplantation (AuBMT) was investigated in a prospective trial for patients with cisplatin-refractory germ cell tumor (GCT). Prognostic factors for survival and treatment-related toxicity were identified. PATIENTS AND METHODS: Fifty-eight patients with refractory GCT were treated with high-dose carboplatin, etoposide, and cyclophosphamide plus AuBMT. Prognostic factors for toxicity and survival were examined in multivariate analyses. RESULTS: Twenty-three patients (40%) achieved a complete response and 12 (21%) are alive and free of disease at a median follow-up time of 28 months. Myelosuppression was severe and there were seven (12%) treatment-related deaths. Independently predictive factors that resulted in faster blood count recovery were the use of granulocyte colony-stimulating factor (G-CSF) for the number of days to neutrophil count recovery (P = .013) and prior treatment with cisplatin limited to six cycles or less for the number of days to platelet count recovery (P = .0012). Both were predictive for the number of days of hospitalization (P = .04 and .03, respectively). The two independently predictive variables for survival were pretreatment level of HCG; human chorionic gonadotrophin (HCG; < or = 100 times the upper limit of normal [xnl] v > 100 xnl, P = .02) and the presence of retroperitoneal metastases (yes or no, P = .04). Patients grouped by HCG < or = 100 xnl with retroperitoneal metastases, HCG < or = 100 xnl without retroperitoneal metastases, and all patients with HCG more than 100 xnl had median survival times of 14, 11, and 3 months, respectively (P = .04). CONCLUSION: High-dose carboplatin, etoposide, and cyclophosphamide is an effective therapy for patients with refractory GCT, and results in a complete response proportion of 40% and a 2-year survival rate of 31% at a median follow-up time of 28 months. This was accomplished in a group of patients with a dismal prognosis to conventional-dose therapy.