Does ifosfamide therapy improve survival of patients with dedifferentiated chondrosarcoma?

Background: Dedifferentiated chondrosarcoma remains a significant therapeutic challenge. Studies performed to date have not identified efficacious chemotherapy regimens for this disease. Questions/purposes: We sought to (1) evaluate the disease-specific survival at 2 and 5 years of patients with dedifferentiated chondrosarcoma; (2) assess the prognostic variables (both patient- and treatment-related), including the use of chemotherapy with ifosfamide, that relate to survivorship; and (3) assess specific toxicities associated with ifosfamide use. Methods: Data from 41 patients with dedifferentiated chondrosarcoma diagnosed and treated at the University of Texas MD Anderson Cancer Center from 1986 to 2010 were analyzed for demographics, treatments, oncologic outcomes, and prognostic variables. There were 14 women and 27 men. The mean age at diagnosis was 58 years (range, 26-86 years). Seven patients presented with metastasis. Surgical resection alone was performed in 11 patients; resection and chemotherapy in 26 patients; resection and radiotherapy in two patients; and resection, chemotherapy, and radiotherapy in two patients. Ifosfamide-based regimens were used for 16 patients. In general, ifosfamide was used when the tumor was located in the trunk or if cisplatin was discontinued as a result of toxicity. Minimum followup was 8 months (median, 68 months; range, 8-281 months). Survival was estimated using Kaplan-Meier plots and analyzed by using the Cox proportional hazards model. Results: Disease-specific survival rates at 2 and 5 years were 33% and 15%, respectively. Multivariate analysis revealed that treatment without ifosfamide-based chemotherapy was the only independent negative prognostic factor for disease-specific survival (hazard ratio, 0.4; 95% confidence interval, 0.17-0.92; p = 0.03). Ifosfamide was discontinued in a patient as a result of renal dysfunction and was decreased in dose in another patient who developed encephalopathy. Conclusions: In this small retrospective study, it appeared that ifosfamide-based adjuvant chemotherapy combined with surgical resection offered a treatment advantage compared with patients who did not receive the drug in patients with dedifferentiated chondrosarcoma, although disease-specific survival for patients who have this rare tumor remains dismal. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.