Background: The optimal management of primary angiosarcoma (PAS) and radiation-associated angiosarcoma (RAAS) of the breast remains undefined. Available data show persistently poor survival outcomes following treatment with surgery or chemotherapy alone. The objective of this study was to evaluate long-term outcomes in patients treated with multimodality therapy. Methods: Patients diagnosed with stage I–III PAS or RAAS of the breast were identified from our local tumor registry (2010–2020). Patient demographics, tumor characteristics, and treatment were collected. Primary outcomes were local recurrence (LR), distant recurrence (DR), and median overall survival (OS). A secondary outcome was pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC). Mann–Whitney U, chi-squared, or Fisher exact tests were used to analyze data. Kaplan–Meier curves compared OS for PAS and RAAS. Results: Twenty-two patients met inclusion criteria, including 11 (50%) with RAAS and 11 (50%) with PAS. Compared to PAS patients, RAAS patients were older and had more comorbidities. For RAAS patients, median time from radiation to diagnosis was 6 years (IQR: 5–11). RAAS patients were more likely to have a pCR to NAC (40% vs. 20%, p = 0.72). RAAS patients had a higher LR rate (43% vs. 38%, p = 0.83), and PAS patients were more likely to develop a DR (38% vs. 0%, p = 0.07). Median OS was 81 months in PAS patients and 90 months in RAAS patients (p = 1.00). Discussion: Long-term survival can be achieved in patients with PAS and RAAS who undergo multimodality treatment. NAC can result in pCR. The long-term clinical implications of pCR warrant further investigation.

Flavonoids are part of a large family of polyphenols that are found extensively in fruits and vegetables. This class of compounds has been of considerable medical interest due to their anti-inflammatory and anti-cancer activities. Although extensive effort has been made to identify the biological effects responsible for the chemopreventive activity of these compounds, the exact molecular mechanisms involved are not fully understood. In this study, we focused on the cytotoxic effects of fourteen different flavonoids against a series of breast cancer cell lines and evaluated the induction of cell cycle arrest at G1 or G2/M phase as result of such treatment. We also assessed a possible structure-function relationship for cellular cytotoxicity based on the various chemical structures of flavonoids. The results showed that several flavonoids were cytotoxic in all cell lines even in the absence of certain signaling pathways. In addition, only some flavonoids were able to induce cell cycle arrest, suggesting their cytotoxic potential may be independent of their ability to block cells at G1 or G2/M phases. Our results enabled identification of certain structural properties that are important for the anticancer activity of flavonoids. Finally, these results suggested that cytotoxicity does not depend on a particular signaling pathway.