Neoadjuvant therapy for breast cancer has no benefits on overall survival or on the mastectomy rate in routine clinical practice. A population-based study with a median follow-up of 11 years using propensity score matching

Abstract

Background: Even though neoadjuvant chemotherapy has shown no benefits on overall survival (OS), it is being widely used in the treatment of breast cancer. This is based on the assumption that it may diminish the mastectomy rate and therefore be clinically relevant for patients. Our objective was to assess the impact of neoadjuvant chemotherapy on OS and on the rate of mastectomy in patients with non-metastatic primary operable breast carcinoma in routine practice.

Methods: The Cote d'Or district breast cancer registry was used to analyse the OS and mastectomy rate in patients with invasive primary operable unilateral breast cancer diagnosed between 1982 and 2006. We performed Cox proportional hazard ratio (HR) analyses for OS and multivariate logistic regression for the mastectomy rate for the overall population. Different matching methods based on the propensity score were used as sensitivity analyses to ensure that corrections for selection bias were adequate.

Results: We analysed 1578 patients, among whom 174 had received neoadjuvant chemotherapy. Median follow-up was 11.1 years. There was no difference between the two treatment groups for OS (HR=1.08 (95% confidence interval (CI): 0.77-1.51 for neoadjuvant chemotherapy)). The mastectomy rate was higher among patients treated with neoadjuvant chemotherapy (odds ratio 1.54 (95%CI: 1.03-2.31)). Sensitivity analyses confirmed these results: for OS, there was no difference between the two populations precisely matched using propensity scores (HR 1.08; 95%CI: 0.671-1.65).

Conclusion: Despite long term follow-up, neoadjuvant chemotherapy provided no benefit for either OS or the mastectomy rate in our population.