Cutaneous Radiation-associated Breast Angiosarcoma: Radicality of Surgery Impacts Survival.

OBJECTIVE: Cutaneous radiation therapy (RT)-associated breast angiosarcoma (AS) is a rare consequence of breast RT associated with poor outcomes. Previous small case series have documented high recurrence rates and poor survival. We reviewed our experience and focused on the impact of conservative versus radical resections. METHODS: Data for patients with RT-associated breast AS evaluated at our institution from 1993 to 2015 who underwent surgery were reviewed. RESULTS: Seventy-six women were diagnosed with RT-associated breast AS at a median 85 months from surgery for invasive breast carcinoma or ductal carcinoma in situ. Thirty-eight underwent mastectomy/wide excision with partial skin resection ("conservative") and 38 underwent resection of all or nearly all previously irradiated skin plus mastectomy ("radical"). The radical group (vs the conservative group) more often had multifocal disease (80% vs 56%, P = 0.04), chemotherapy for AS (58% vs 22%, P < 0.01), margin-negative resection (100% vs 73%, P < 0.01), reconstructive surgery (100% vs 13%, P < 0.01), and re-operation (16% vs 3%, P = 0.04). Five-year crude cumulative incidences of local recurrence and distant metastasis for radical versus conservative groups were 23% versus 76% (P < 0.01) and 18% versus 47% (P = 0.02), respectively. Five-year disease-specific survival (DSS) for radical versus conservative groups was 86% versus 46% (P < 0.01), respectively. On multivariable analysis, age, radicality of surgery, and margin were predictive of DSS. CONCLUSIONS: For patients with RT-associated breast AS, radical resection was associated with reduced recurrence rates and improved DSS. Although margin was predictive of DSS, multifocality calls into question the reliability of negative margin assessment.