6. Reconstruction of Chest Wall Defects Following Post-Radiotherapy Angiosarcoma Resection Using External Oblique Myocutaneous Flap

OBJECTIVE: This study aims to compare outcomes, local recurrence rates, and survivability in patients who developed radiation-induced angiosarcoma of the breast who underwent wide local excision (WLE) with primary closure (PC) or WLE with external oblique myocutaneous flap (EOMCF). METHODS: This is a single-center retrospective cohort study evaluating patients over the past ten years with RIAS who underwent PC or EOMCF after WLE. The pathology department provided names and medical record numbers for patients with diagnosis of angiosarcoma. Only patients with angiosarcoma of the breast were included. Patient demographics, breast cancer history, time from radiation, extent of disease, resection margins, recurrence rates, survival, and complications (necrosis, dehiscence, hematoma, seroma, and hernia) were extracted. Descriptive statistics were used to compare outcomes between the cohorts. RESULTS: Seven patients were identified that had the diagnosis of RIAS with four that underwent WLE and PC and three that underwent WLE with EOMCF. No significant differences were detected for baseline demographics, comorbidities, or relevant surgical history between the two groups. The radiation-to-malignancy diagnosis interval was approximately 6.4 and 7.0 years, respectively (p =0.84). There was no significant difference in the tumor size on the pathology specimen (T classification) between the two groups. Patients who underwent PC achieved a mean pathologic margin of 2.7 mm compared to 20.0 mm among the EOMCF group, on average (p=0.001). Average defect length for the PC group and EOMCF group was 23.9 cm and 33.3 cm (p=0.09), and average defect width was 15.7 cm and 20.3 cm (p=0.31), respectively. There was no significant difference in the number of complications, recurrence rate, and five-year survival between the two groups. CONCLUSION: This study demonstrated improved pathological margins for patients who received EOMCF reconstruction following WLE compared to those who were closed primarily. We propose the use of this local workhorse flap as a safe and reliable alternative that allows for wide resection of RIAS. The study was limited by the small sample size due to the rarity of this disease entity. Future studies with larger sample sizes are necessary to provide evidence-based recommendations. CORRESPONDING AUTHOR: Silvy Akrawe, 5540 Franklin Road, Bloomfield Hills, MI 48301, [email protected], 248-635-7071