Ipsilateral breast tumor recurrence (IBTR) in patients with operable breast cancer who undergo breast‐conserving treatment after receiving neoadjuvant chemotherapy

Abstract

There is limited information about the risk factors for ipsilateral breast tumor recurrence (IBTR) after patients undergo breast-conserving surgery plus radiotherapy (breast-conserving treatment [BCT]) subsequent to neoadjuvant chemotherapy (NAC). The objective of the current study was to analyze these risk factors. The authors collected data from 375 patients who underwent BCT and received NAC and analyzed the risk of IBTR associated with undergoing BCT after NAC. The usefulness of the MD Anderson Prognostic Index (MDAPI) for IBTR also was validated using the current data set. The median follow-up was 47.8 months, and the 4-year IBTR-free survival rate was 95.6%. Multivariate analysis demonstrated that estrogen receptor (ER) status and multifocality of the residual tumor were associated significantly with IBTR-free survival. In addition, patients who had ER-positive and human epidermal growth factor 2 (HER2)-negative tumors did not develop IBTR during the observation period. Although prognostic stratification according to MDAPI was relatively good for the prediction of IBTR in the study patients, the IBTR rate in the high-risk group was not very high and was lower than that in the intermediate-risk group. Multivariate analyses demonstrated that IBTR was an independent predictive factor for overall survival. ER status and multifocality of the residual tumor after NAC were independent predictors of IBTR after BCT. The MDAPI was barely adaptable to the study patients in terms of predicting IBTR. Patients with ER-positive and HER2-negative tumors had a favorable prognosis, whereas patients who developed IBTR after NAC had significantly worse overall survival. The authors propose a new IBTR prognostic index using the 2 factors that were identified as predictive of IBTR: ER status and multifocality of the residual tumor.