Comparisons of breast conserving therapy versus mastectomy in young and old women with early-stage breast cancer: long-term results using propensity score adjustment method

Abstract

This study aimed to compare the effect of BCT versus mastectomy on the recurrence and survival of different-aged patients, and to investigate whether effects of BCT versus mastectomy on survival of young patients were consistent with those of old patients. Data on women with primary invasive breast cancer between 2007 and 2011 were extracted from the institutional database of Breast Center. Disparities in hormone receptor, tumor size, lymph node status, and Her-2 status between BCT and mastectomy groups were adjusted using the propensity score (PS) adjustment method. Patients were divided by age into two groups (≤ 40years and > 40years). We assessed proportions of local recurrence (LR), distant disease-free survival (DDFS), disease-free survival (DFS), and breast cancer-specific survival (BCSS) in different-aged groups; this assessment was further stratified by surgical treatment. A total of 2964 patients were included; 565 (19%) were aged ≤ 40years. In the entire cohort, hazard ratios (HR) of BCT versus mastectomy for DDFS and DFS were 0.56 (P = 0.029) and 0.55 (P = 0.008), respectively. After PS adjustment, there was no significant difference between BCT and mastectomy in LR, DDFS, DFS and BCSS in the young age group. In the old age group, women who underwent BCT exhibited improved DDFS (HR 0.57, 95% CI 0.39-0.84, P = 0.004). BCT did not significantly affect survival outcomes of young patients with breast cancer. Superior survival of BCT compared to mastectomy was observed only in old patients.