De-escalating axillary surgery in ductal carcinoma in situ undergoing mastectomy with immediate reconstruction: Is routine sentinel lymph node biopsy an overtreatment?

Abstract

The role of sentinel lymph node biopsy in patients with ductal carcinoma in situ undergoing mastectomy remains controversial. Current guidelines recommend sentinel lymph node biopsy at the time of mastectomy because of concerns regarding occult invasive disease and the loss of lymphatic mapping after breast removal. However, axillary metastases are uncommon in ductal carcinoma in situ, and routine sentinel lymph node biopsy may represent overtreatment in selected patients. This study aimed to identify clinicopathologic factors associated with nodal positivity in order to support a selective approach to sentinel lymph node biopsy. We retrospectively reviewed 188 consecutive patients with a preoperative diagnosis of ductal carcinoma in situ who underwent mastectomy with immediate implant-based reconstruction between 2014 and 2024 at a single institution. Clinicopathologic characteristics, rates of upstaging to invasive carcinoma, and sentinel lymph node status were analyzed. Associations between nodal involvement and clinical or pathologic variables were evaluated, and findings were compared with predictors identified in the literature. Sentinel lymph node biopsy was performed in all patients. Overall, 49 patients (26.1%) were upstaged to invasive carcinoma. Sentinel lymph node metastases (pN1mi/pN1) were identified in 13 patients (6.9%). Multifocal disease (P = .023), the presence of an invasive component (P < .001), histologic subtype (P < .001), and pathologic tumor size (P < .0001) were significantly associated with nodal positivity. No significant associations were observed with menopausal status, tumor grade, or hormone receptor and human epidermal growth factor receptor 2 status. Routine sentinel lymph node biopsy may not be necessary for all patients with ductal carcinoma in situ undergoing mastectomy with immediate reconstruction. Careful patient selection based on preoperative risk factors can allow safe omission of sentinel lymph node biopsy, reducing surgical morbidity without compromising oncologic safety. Our findings suggest that routine sentinel lymph node biopsy in this specific setting may represent systematic overtreatment.