P070 An update on radiation-induced angiosarcoma of the breast: A diagnostic and management challenge

Background: Post-radiation angiosarcoma (AS) of the breast, also known as radiation-associated angiosarcoma (RAAS) or radiation-induced angiosarcoma (RIAS), is a rare complication after breast radiotherapy. The diagnosis and management of post-radiation AS is challenging because of its non-specific but aggressive presentation. This study aims to examine the experience of a local health district with post-radiation AS to improve awareness of this condition. Methods: A retrospective case series was performed on patients diagnosed with post-radiation AS within Western Sydney Local Health District between 2000-2021. Eligibility criteria included patients with histologically proven breast angiosarcoma and a history of past breast radiotherapy. Results: 11 patients had post-radiation AS of the breast. The annual incidence was 1 in 18,000 of the breast radiotherapy treated population. Descriptive analysis was performed on six patients. The median age was 67 years, with a median latency period of 5.5 years. All patients presented with non-specific skin changes. Core/punch biopsy was inconclusive in five patients. Mastectomy was the mainstay of treatment. Three patients had disease recurrence. The five-year survival rate was 68%. Conclusion: Post-radiation AS of the breast is a rare disease associated with a poor prognosis due to its aggressive nature and high recurrence rate. Diagnosis is challenging with high false-negative rates associated with imaging and biopsy. It is important to maintain a high index of suspicion in patients treated with past breast radiotherapy.