Primary and Radiation-induced Breast Angiosarcoma: Clinicopathologic Predictors of Outcomes and the Impact of Adjuvant Radiation Therapy.

Background: Mammary angiosarcoma (AS) is an aggressive malignancy with high recurrence rates and poor overall survival. Limited data exist to guide treatment. We aimed to identify patterns of failure in the context of adjuvant radiation and to identify prognostic indicators to better guide management.

Methods: Thirty-five patients with breast AS at UPMC Magee Women's Hospital from June 1994 to March 2011 were retrospectively reviewed. Pathology was rereviewed for 22 patients by an expert breast pathologist using an objective scoring system, partly based on the Rosen grading scheme. All patients completed R0 resection, with 14 of them receiving adjuvant radiotherapy (RT) (82% of which represented reirradiation for radiation-induced AS).

Results: At a median follow-up of 20 months (range, 3 to 178 mo), the primary mode of failure was local with 32% local first failure. Tumor size >5 cm, radiation-induced etiology, and the omission of adjuvant RT were important prognostic factors of tumor control and survival. Histopathology including necrosis, number of mitotic figures, endothelial tufting, solid/spindle cell foci, and the combined scoring system were prognostic for recurrence patterns.

Conclusions: Breast AS has high rates of local failure despite R0 resection, which may be improved with adjuvant RT, even in the reirradiation setting. Histopathology is prognostic for recurrence patterns.