Abstract P3-19-11: Long-term outcomes of primary and secondary angiosarcomas of the breast: A 20-year single-center experience

Abstract

Abstract Introduction: Sarcomas of the breast comprise less than 1% of breast malignancies. Angiosarcomas are aggressive tumors that arise in the breast more than other sites, radiation-associated angiosarcomas (RAA) account for 0.05 - 0.2% of breast malignancies. Primary angiosarcomas are mostly diagnosed in women between 30-50 years of age while RAA occur after a prolonged latency following radiation therapy. This study aims to evaluate the management and subsequent outcomes of breast angiosarcomas (BAS) at the McGill University Health Centre (MUHC), a large tertiary care center, from 2000-2020. Methods: Using our institutional cancer registry database, we identified patients with histologically confirmed BAS diagnosed between 2000- 2020. Data was collected retrospectively including demographics, operative and oncologic interventions, and outcomes. Descriptive statistics were used to summarize the characteristics of the study population. Kaplan Meier curves were used to describe progression-free survival probability, overall survival, and corresponding 95% confidence intervals. Results: A total of 14 patients were identified including 3 (21.4%) with primary BAS and 11 (78.6%) with radiation-associated angiosarcoma (RAA). The mean age of RAA patients at presentation was 71.4 years (range 59-82), and 44 years for the primary BAS (range: 28-53). The mean latency period in developing RAA was 8.0 years (range 4.4-13.3). Treatment of primary angiosarcomas included surgery in all 3 patients, radiotherapy (RT) in 2 and chemotherapy in one who received neoadjuvant chemotherapy and radiotherapy followed by total mastectomy. Treatment of RAA (n=11) included surgery (100%), radiotherapy (18%), chemotherapy (9%). Total mastectomy was performed in ten (91%) patients, one of whom received neoadjuvant chemotherapy and two adjuvant RT. Partial mastectomy (PM) was performed in one patient. After a median follow-up time of 32.5 months (range 0-172), following initial treatment, five patients (35.7%) experienced local recurrence, two of whom had had positive margins after initial surgery. Salvage treatments included wide excision (100%), adjuvant RT in two patients (66.6%) and chemotherapy at time of development of distant metastasis in one. In the primary angiosarcoma population, after accounting for one patient that was lost to follow-up, none experienced recurrence or death. Overall survival probability in the whole study population and in the secondary RAA group was 100% at 36 months. The PFS at 24 months was 51.3% (95% CI: 29.6-88.8%) for the whole population and 41.6% (95% CI: 19.9-86.8%) in the RAA group. In the RAA group, out of the five patients that recurred locally, one patient developed a third malignancy (endometrial) and three patients are currently alive. Conclusion: Overall, our 20-year single center experience confirms the rare nature of BAS. Despite a favorable overall survival rate, local recurrence remains a significant challenge. Our results underscore the importance of optimal salvage therapies such as wide surgical excisions, RT, and chemotherapy that in our series lead to better-than-expected overall survival. Given the rarity of BAS, patients should be managed in large tertiary care centers where multidisciplinary management and clinical expertise can guide salvage approaches. Citation Format: Marwan Tolba, Vanessa Di Lalla, Farzin Khosrow-Khavar, Ayesha Baig, Carolyn Freeman, Valerie Panet-Raymond. Long-term outcomes of primary and secondary angiosarcomas of the breast: A 20-year single-center experience [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-11.