Survival of Patients with Metastatic Malignant Pheochromocytoma and Efficacy of Combined Cyclophosphamide, Vincristine, and Dacarbazine Chemotherapy

Abstract

About 10% of pheochromocytomas are malignant. Exact survival has not been reported, nor has an analysis of the efficacy of chemotherapy on survival time. The aim of this study was to analyze the survival curves and survival times of patients with malignant pheochromocytoma and to determine the efficacy of chemotherapy on prolongation of life. An inception cohort and Kaplan-Meier survival analysis was conducted. Thirty-two patients with metastasized malignant pheochromocytoma were analyzed for survival. Twenty-five patients had undergone excision of their primary tumors. Survival curves were compared among the 16 patients in this group treated with combined chemotherapy using cyclophosphamide, vincristine and dacarbazine (CVD) and the nine patients not treated with chemotherapy. The survival curve of the 32 patients declined continuously and linearly to at least 20 yr after the diagnosis of pheochromocytoma. The 50% survival rate was estimated to be 14.7 yr. In the 25 patients whose primary tumor was excised, patients who already had metastases at the time of pheochromocytoma diagnosis had better survival than those whose metastases were found later. The survival rate after diagnosis of metastasis was worse in the CVD group than in controls. When the effects of CVD were examined after stratifying several factors, female gender and adrenal origin of tumor were found to be negative prognostic factors for CVD chemotherapy. The present study revealed a long survival time. CVD chemotherapy was not shown to extend survival, especially for women and patients with adrenal gland-derived primary tumors.