Outcome and risk factors for local recurrence after breast conserving surgery in patients affected by ductal carcinoma in situ

BACKGROUND: Ductal carcinoma in situ (DCIS) is a tumor with long term survival and low local recurrence rate. Al-though the progression of these lesions is rare, the current guidelines recommend breast conservating surgery (BCS) with adjuvant radio and/or endocrine therapy, often resulting in an overtreatment for patients. The aim of this single-center study was to evaluate the long-term outcome of the breast conservating surgery of DCIS followed by adjuvant radio and/ or endocrine therapy and to identify prognostic factors associated with the risk of recurrence. METHODS: Patients treated for DCIS with BCS and radiation therapy between March 2006 and January 2019 were retrospectively reviewed using a prospectively maintained database. Analysis of the potential risk factors was performed to evaluate the risk of subsequent ipsilateral and contralateral recurrence. RESULTS: Out of 2894 patients, two hundred eighty-eight (10%) patients were treated for DCIS. After a median follow-up of 85 months (IQR 27-124), the incidence of recurrence was 6% (18 patients). Nine of them (3%) had an ipsilateral local recurrence (LR) with a median disease-free survival of 19 months (IQR 12-35). The remaining nine patients had contralateral metachronous breast cancer (CBC) with a median DFS of 29 months (IQR 14-36). Margin status, multifo-cality, hormone receptor status and Her-2/Basal-like subtype were identified as risk factors for the local recurrence with a OR of 5.58 (1.44-21.54), 7.46(1.89-24.48) 0.25 (0.06-0.96) and 4.86 (1.26-18.71) respectively. CONCLUSIONS: DCIS had been confirmed to have long term survival. Margin status, multifocality, hormone receptor status and Her-2/Basal-like subtype could be identified as reliable risk factors for the progression of the disease.