Disease recurrence in patients undergoing mastectomy for ductal carcinoma in situ.

Purpose: With DCIS incidence on the rise, up to 30% of patients undergo mastectomy for Ductal carcinoma in situ (DCIS) (Nash and Hwang, in: Ann Surg Oncol 30(6):3206-3214, 2023). Local recurrence rates after mastectomy for DCIS are reportedly low, but risk factors for recurrence are not known (Kim et al., in: J Cancer Res Ther 16(6):1197-1202, 2020). We aim to define risk factors associated with ipsilateral breast cancer recurrence in patients undergoing mastectomy for DCIS.

Methods: We aimed to identify risk factors that may contribute to recurrence of breast cancer following mastectomy for pure DCIS. We hypothesized that close or positive mastectomy margins, age at diagnosis, extent of breast disease and mutation carriers would be associated with increased risk of recurrence. We performed a retrospective chart review of patients who underwent unilateral or bilateral mastectomies for pure DCIS at a single academic tertiary referral center from 2013 to 2023.

Results: There were 165 patients who met inclusion criteria with an average length of follow-up of 39.9 months. On final surgical pathology, the average span of DCIS was 33.7 mm (± 24.6 mm). Hormone receptor positive disease was identified in 80.6% of the patient cohort. For margin status, 23 patients (14%) had < 1 mm margins on final pathology and of those, 1 received adjuvant radiation therapy and 4 returned to the OR for re-excision. Only 1 (0.6%) patient had ipsilateral disease recurrence during the study period.

Conclusion: Recurrence after mastectomy for pure DCIS is a rare event and in our study sample, only one recurrence occurred. Risk factors for recurrence appear unrelated to margin status, age, extent of DCIS, or pathogenic mutation (ElSherif et al., in Am J Surg 226(5):646-651, 2023).