Alveolar soft part sarcoma: clinical course and patterns of metastasis in 70 patients treated at a single institution

Background: Alveolar soft part sarcoma (ASPS) is a rare form of soft tissue sarcoma. Brain metastases have been reported to be a common feature of Stage IV ASPS, and recent practice guidelines recommend routine intracranial imaging as part of the staging evaluation in all patients who present with ASPS.

Methods: The authors performed a comprehensive retrospective review of the clinical presentation, treatment, outcome, and patterns of failure in a consecutive series of patients with localized (American Joint Committee on Cancer [AJCC] Stages II/III) or metastatic (AJCC Stage IV) ASPS who presented to a tertiary care cancer center between 1959 and 1998.

Results: Seventy-four patients were identified from the database searches. The anatomic distribution of their primary tumors included: extremities, 44 patients (60%); trunk, 15 patients (20%); head and neck, 9 patients (12%); and retroperitoneum, 6 patients (8%). The median tumor size was 6.5 cm (range, 1.2-24 cm). The AJCC stage at presentation was Stage II or III in 35% of the patients and Stage IV in 65% of the patients. The 5-year actuarial local recurrence free, distant recurrence free, disease free, and overall survival rates among the 22 patients with localized ASPS were 88%, 84%, 71%%, and 87%, respectively. At a median follow-up of 9 years, 2 of 22 patients with localized disease had developed local recurrences and 3 had developed metastatic disease (all to the lung only). Brain metastases were noted in 9 of 48 patients who presented with Stage IV (M1) disease (19%) and always were noted in association with metastasis to other sites. The median survival of patients with M1 disease was 40 months, with a 5-year survival rate of 20%.

Conclusions: Long term follow-up of patients with localized ASPS reveals a relatively indolent clinical course with relatively low rates of local and distant recurrence. In patients with Stage IV ASPS, brain metastases were observed only as part of more disseminated disease. The observations of the current study do not support current practice guidelines for the staging of patients with ASPS and suggest that selective rather than routine intracranial imaging should be used in patients presenting with ASPS.