Extraskeletal myxoid chondrosarcoma: a retrospective review from 2 referral centers emphasizing long-term outcomes with surgery and chemotherapy.

BACKGROUND: Extraskeletal myxoid chondrosarcoma (EMC) is a genetically distinct sarcoma with a propensity for local recurrence and metastasis despite an indolent course. To the authors' knowledge, there are limited data examining chemotherapy outcomes as a guide to therapeutic decisions for unresectable disease.
METHODS: The clinical behavior and treatment responses of 87 patients with EMC who were seen at 2 institutions between 1975 and 2008 were examined.
RESULTS: The median age of the patients at the time of diagnosis was 49.5 years, with a male-to-female ratio of 2:1. For patients presenting without metastases, 37% developed local recurrence (median time of 3.3 years) and 26% developed distal recurrence (median time of 3.2 years). Approximately 13% of patients presented with metastases. The 5-year, 10-year, and 15-year overall survival rates were 82%, 65%, and 58%, respectively. Twenty-one patients received 32 evaluable courses of chemotherapy. No significant radiologic or clinical responses were noted. The median time to disease progression while receiving chemotherapy was 5.2 months. The best physician-assessed response to chemotherapy was stable disease for at least 6 months in 25% of patients, stable disease for <6 months in 41% of patients, and disease progression in 34% of patients. The estimated progression-free survival rates at 3 months, 4 months, 6 months, and 9 months were 69%, 65%, 40%, and 26%, respectively.
CONCLUSIONS: This retrospective review highlights the poor response rate to chemotherapy and emphasizes aggressive control of localized disease as the primary approach to management. Although there are biases inherent in retrospective analyses, these data provide a benchmark for time to disease progression for the study of new agents for the treatment of patients with this diagnosis.