A) Number of primary (PBA) and secondary (SBA) breast angiosarcoma cases in SEER by year of diagnosis B) Incidence rate over time of primary and secondary breast angiosarcoma. The rate of increase of SBA cases was significantly different from that of PBA (p = 0.003). Data presented with best fit line (linear regression, SBA, R square = 0.549, F 24.4; PBA, R square = 0.0568, F = 1.21. C) Incidence rate in patients with a primary breast cancer of developing a secondary breast angiosarcoma (R square 0.312, F 10.4, p=0.0037). D) Percent of patients with breast carcinoma receiving radiation E) Of patients who had surgery for breast carcinoma, percent who had breast conservation surgery. Abbreviations: PBA, Primary breast angiosarcoma; SBA, secondary breast angiosarcoma. Dotted line = 95% confidence interval.