Short-term mortality in older (≥70 years) patients with early breast cancer treated with neo‐/adjuvant chemotherapy: A Swedish nationwide retrospective population-based study

Abstract

Introduction

There are substantial differences in the utilization of chemotherapy between younger and older patients, mainly due to the higher risk for adverse events among older patients. Short-term mortality after chemotherapy could reveal fatal side effects of treatment. The aim of this study was to explore the impact of treatment setting (neoadjuvant vs. adjuvant) and different chemotherapeutic agents on short-term mortality among older patients with early breast cancer.

Material and Methods

The population-based, national, research database BCBaSe 3.0 was used as a data source to identify older (≥70 years old) patients with stage I–III breast cancer, diagnosed between 2008 and 2019, who received neoadjuvant or adjuvant chemotherapy. Primary outcome was short-term mortality defined as death due to any cause within one year after breast cancer diagnosis. Multivariable logistic regression analysis was applied to investigate the impact of treatment setting and different chemotherapeutic agents (anthracycline-based vs. taxane-based vs. sequential anthracyclines and taxanes) on outcome, adjusted for potential confounders.

Results

In total, 4,072 older patients were treated with neoadjuvant or adjuvant chemotherapy and median age was 73 years (quartile [Q]1–Q3; 71–75). The one-year mortality rate was 1.5 % (95 % confidence interval [CI]: 1.2–1.9 % [63 of 4072 patients]). Risk factors independently associated with one-year mortality were older age, larger tumor size, positive nodal status, presence of triple negative breast cancer, and use of neoadjuvant as compared to adjuvant chemotherapy (odds ratio [OR]: 2.00, 95 % CI: 1.04–3.84). No association was found between type of chemotherapeutic regimen and one-year mortality. Median time to death was 7 months (interquartile range: 5–9). The reason for death was mainly classified as breast cancer-related (neoadjuvant: 78 %, n = 14; adjuvant: 49 %, n = 22), followed by potential treatment-related deaths (neoadjuvant: 11 %, n = 2; adjuvant: 27 %, n = 12).

Discussion

The short-term mortality rate at first year after diagnosis among older (≥70 years) patients with breast cancer was relatively low. The higher risk among patients treated with neoadjuvant chemotherapy could be attributed to residual confounding and deserves further evaluation. The low risk of potential treatment-associated death suggests that chemotherapy in this respect is safe, and older patients should not be disqualified for this treatment.