Does a Close Surgical Margin for Ductal Carcinoma In Situ Associated with Invasive Breast Carcinoma Affect Breast Cancer Recurrence?

Purpose: Our aim was to determine if a close surgical margin (<2 mm, but no ink on tumor) for ductal carcinoma in situ (DCIS) associated with invasive breast cancer (IBC) leads to an increased rate of ipsilateral breast tumor recurrence (IBTR).Patients and Methods: Six hundred and twenty-eight patients with T1-2 IBC who underwent breast conserving therapy (BCT) and had no ink on tumor between 2009 and 2017 in our institution were included in the study. Age, tumor size, axillary lymph node status, resection margin status of DCIS as closer than 2 mm or ≥2 mm, DCIS as present or absent, extensive intraductal component as yes or no were investigated. All patients were followed-up for IBTR.Results: The median age was 50 years (range, 29-82), and median tumor size was 25 mm (range, 5-50). Median follow-up time was 56 months (range, 12-114). Of the 628 IBC patients, 440 (70%) were found to be associated with DCIS. Of the 440 patients with DCIS, 119 (27%) had a close margin (<2 mm) and 321 (73%) had a margin ≥2 mm for DCIS. Among 440 IBC patients associated with DCIS, there were three local recurrences. One developed in a patient who had a close surgical margin for DCIS, and in the other two patients, surgical margins were ≥2 mm.Conclusions: No ink on tumor is an adequate margin for IBC associated with DCIS in patients who undergo BCT and it is not associated with increased IBTR.