The impact of age group in breast cancer survival outcome according to neoadjuvant treatment response: A matched case–control study

This study aimed to investigate the effectiveness of neoadjuvant chemotherapy in patients with breast cancer in different age groups and evaluate the impact of age group on survival outcome according to different treatment responses. Data were retrospectively collected from the cancer registry database of Kaohsiung Medical University Hospital in Taiwan under an approved protocol. Overall, 96 elder patients (aged >50 years) and 96 younger controls (aged ≤50 years) who received neoadjuvant chemotherapy and breast surgical treatment were examined after 1:1 matching. Logistic regression analysis was used to investigate the effectiveness of treatment response in patients of different age groups. Additionally, the Kaplan-Meier estimator and log-rank test were performed to evaluate the effect of age group and treatment response on disease-free and overall survival (OS). Although no direct significant association was found between age group and treatment response, several significant results were found in treatment response stratification analysis. Among 16 pathological complete response (pCR) patients, elder patients showed significantly greater 5-year disease-free survival (DFS) than younger patients (DFS rate, 85.7% vs. 0%, p = 0.041). However, in 176 non-pCR patients, elder patients showed poor DFS compared to younger patients (DFS rate, 16.6% vs. 32.3%; log-rank test, p = 0.031). With limited sample size and study design, our study results demonstrate that patients aged >50 years who achieved pCR after neoadjuvant chemotherapy could obtain better survival outcome than younger patients. However, the younger patients showed no survival benefits regardless of pCR status.