Background: Radiation-associated angiosarcoma (RAAS) is a devastating disease occasionally observed in breast cancer patients treated with radiation. Due to its rarity, our knowledge-of disease risk factors, epidemiology, treatment, and outcome-is extremely limited. Therefore, we sought to identify clinicopathologic factors associated with local and distant recurrence and disease-specific survival (DSS). Methods: Radiation-associated angiosarcoma was defined as pathologically confirmed breast or chest wall angiosarcoma arising within a previously irradiated field. A comprehensive search of our institutional tumor registry (1/1/93 through 2/28/11) was used to identify patients (n = 95 females). Patient, original tumor, RAAS treatment, and outcome variables were retrospectively retrieved and assembled into a database. Results: The median follow-up for all RAAS patients was 10.3 (range, 2.4-31.8) years. The latency period following radiation exposure ranged from 1.4 to 26 (median, 7) years. One-year and 5-year DSS rates were 93.5 and 62.6 %, respectively. Reduced risk of local recurrence was observed in patients who received chemotherapy (P = 0.0003). In multivariable analysis, size was found to be an independent predictor of adverse outcome (P = 0.015). Conclusions: Our study demonstrates that RAAS exhibits high recurrence rates. It also highlights the need for well-designed, multicenter, clinical trials to inform the true utility of chemotherapy in this disease.