Correlation of pathological complete response with outcomes in locally advanced breast cancer treated with neoadjuvant chemotherapy: An ambispective study

Abstract

Background: Neoadjuvant chemotherapy response rates in locally advanced breast cancer (LABC) vary significantly among Indian patients, and the factors affecting pathological complete response (pCR) rate are not clear in this population.Objectives: This study was aimed at identifying the various clinicopathological features associated with achieving pCR and its effect on disease-free survival (DFS) and overall survival (OS) among Indian women diagnosed with LABC.Materials and Methods: Women diagnosed with LABC between 2013 and 2019 and who received neoadjuvant chemotherapy followed by surgery and radiotherapy were ambispectively analyzed for clinicopathological responses and survival outcomes. Factors associated with pCR and the role of pCR as a prognostic factor for survival outcomes were examined. Results: After neoadjuvant chemotherapy, pCR was achieved in 99 (23.3%) patients, with the highest rates noted in patients with triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2 (HER2)-positive tumors. Compared to hormone receptor-positive tumors with HER2-negative status, all other tumor groups had significantly higher odds of achieving pCR after neoadjuvant chemotherapy (TNBC: adjusted odds ratio [aOR], 4.58 [95% CI, 2.20–9.53]; hormone receptor- and HER2+: aOR, 3.93 [95% CI, 1.66–9.27]; hormone receptor + and HER2+: aOR, 2.78 [95% CI, 1.20–6.44]). Hormone receptor status and attainment of a pCR after neoadjuvant chemotherapy were associated with better DFS and OS outcomes particularly in patients with HER2-positive and TNBC tumors.Conclusions: Patients who attain a pCR following neoadjuvant chemotherapy have improved survival outcomes; pCR rates vary by hormone and HER2 receptor status. Therapeutic approaches such as anti-HER2 and platinum-based regimens may be considered for achieving better pCR rates. The use of biomarkers for the identification of individuals with breast cancer who will not benefit from neoadjuvant chemotherapy should be considered along with early cancer detection strategies.