Alveolar soft part sarcoma: a rare and enigmatic entity.

UNLABELLED: Alveolar soft part sarcoma is a rare malignant tumor with unusual clinical behavior. Treatment of alveolar soft part sarcoma has been difficult to evaluate because of the small numbers of cases seen, but it seemed that although treatment of the primary tumor in alveolar soft part sarcoma often is successful, treatment of metastatic tumors is unsuccessful. A review of outcome after treatment of primary and metastatic disease in the 15 patients in our database with alveolar soft part sarcoma was done in order to evaluate this issue. Nine of 15 patients presented with metastatic disease and one further patient developed metastases. Treatment of primary tumors involved surgical excision in all but one patient and radiation in all patients. Adjuvant chemotherapy was administered to one patient with localized disease and to six patients with metastatic disease. There were no local recurrences. Treatment of metastatic tumors involved chemotherapy in seven patients, metastectomy in three patients, and radiation in two patients. All instances of the metastatic disease either recurred or progressed. Overall survival was 75% at 5 years and 40% at 10 years with a mean survival of 6.5 years, despite the high number of patients with metastatic disease. Current treatment results in good local control of primary tumors, but poor control of metastatic tumors. New approaches to treatment of metastatic alveolar soft part sarcoma must be investigated and applied. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.