Feasibility and Prognostic Analysis of Neoadjuvant Therapy Followed by Breast-Conserving Surgery for Invasive Ductal Carcinoma Combined with Ductal Carcinoma in Situ.

Objective: This study aim to investigate the oncological safety of neoadjuvant therapy (NAT) followed by breast-conserving surgery (BCS) for invasive ductal carcinoma (IDC) patients with the presence of ductal carcinoma in situ (DCIS) on pre-NAT biopsy.

Methods: The data of women with IDC who underwent radical surgery between January 2013 and December 2021 were retrospectively reviewed from two institutions. The study endpoints were 5-year disease-free survival (DFS) and local recurrence-fee survival (LRFS).

Results: Overall, 994 eligible patients were enrolled. Patients with IDC with DCIS (n = 277) and patients undergoing BCS (n = 285) were selected separately for prognostic analysis. For patients with IDC with DCIS, the 5-year DFS (p = 0.517) and 5-year LRFS (p = 0.397) rates of the patients undergoing BCS were similar to those of patients undergoing mastectomy after propensity score matching. In addition, the 285 patients who underwent BCS were divided into the IDC + DCIS and IDC groups. The 5-year DFS (p = 0.394) and 5-year LRFS (p = 0.341) rates were similar between the IDC and IDC + DCIS groups.

Conclusion: NAT followed by BCS combined with adjuvant radiotherapy is a safe and feasible treatment option in patients with IDC with DCIS under the premise of strict adherence to the surgical indications and adequate incision margins.