Higher Locoregional Recurrence in Hormone Receptor-Negative Breast Cancer Patients with Residual Disease after Neoadjuvant Treatment Undergoing Breast Conservation Surgery

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Background:</jats:bold> Neoadjuvant chemotherapy (NAC) has been the standard treatment for locally advanced breast cancer for the purpose of downstaging or for conversion from mastectomy to breast conservation surgery (BCS). There is still a high locoregional recurrence (LRR) rate after NAC. The aim of this study was to determine predictive factors for locoregional recurrence (LRR) in breast cancer patients after NAC. <jats:bold>Materials and Methods:</jats:bold> Between 2005 and 2017, 1047 breast cancer patients underwent BCS or mastectomy after NAC in Chang Gung Memorial Hospital, Linkou. We obtained data regarding patient and tumor characteristics, chemotherapy regimens, clinical tumor response, tumor subtypes and pathological complete response (pCR), type of surgery, and recurrence.<jats:bold>Results</jats:bold>: The median follow-up time was 45.1 months (range 0.1-160.3 months). The mean initial tumor size was 4.89 cm (SD ±2.95 cm). Of the 1047 NAC patients, 232 (22.2%) achieved pCR. The BCS and mastectomy rates were 41% and 59%, respectively. Overall, 240 patients experienced tumor recurrence (22.9%). Thirty-five cases of LRR (14.3%) were noted following BCS, of which 4.3% achieved pCR. Multivariate analysis indicated that independent factors for the prediction of LRR included hormone receptor negative/human epidermal growth factor receptor 2 positive (HR-/HER2+) subtype, HR-/HER2- subtype, and failure to achieve pCR. Further investigation according to the molecular subtype showed that following BCS, HR-/HER2+ non-pCR group had significantly increased LRR compared with the HR+/HER2+ pCR group (22.2% vs 6.3%, p&lt;0.05), and the HR-/HER2-non-pCR group had significantly increased LRR compared with the HR-/HER2-pCR group (0% vs 20.4%, p&lt;0.005). <jats:bold>Conclusion:</jats:bold> Pathological response after NAC is related to the risk of developing LRR. The LRR rate was higher in non-pCR patients after NAC, especially in hormone receptor-negative patients undergoing BCS. Therefore, both the pathological response status and molecular subtype should be carefully considered when considering candidates for BCS after NAC.</jats:p>