Clinical Outcomes for Primary and Radiation-Associated Angiosarcoma of the Breast with Multimodal Treatment: Long-Term Survival Is Achievable

Simple Summary Primary angiosarcoma of the breast (PAS) and radiation-associated angiosarcoma of the breast (RAAS) are rare sarcomas that affect the inner lining of blood vessels in the breast with incidences of 0.05% and 0.02%, respectively. This study demonstrates that multimodal treatment with neoadjuvant chemotherapy, radiation therapy (in some patients), surgery, and adjuvant chemotherapy may result in optimal clinical outcomes, including prolonged survival. While this study reflects a small sample size, it demonstrates that neoadjuvant chemotherapy, especially when associated with a pathologic complete response, may contribute to these substantial results. Breast angiosarcoma, however, remains a rare disease and prospective, multi-institutional studies need to be performed to overcome the inherent limitations associated with low incidence. Abstract 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.