OBJECTIVES: There has been an increasing trend of chemotherapy use before (neoadjuvant chemotherapy [NAC]) versus after surgery (adjuvant chemotherapy [AdC]) in breast cancer, but little is known if this exists among older women. This study examined NAC use trends among older women with breast cancer, as well as factors associated with NAC use.

METHODS: Older women (>65) diagnosed with stage I–III breast cancer during 2010–2017, treated with both surgery and chemotherapy, and continuously enrolled were included. The data source was the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. The outcome was receipt of NAC or AdC and patients were placed into one of six strata, which were based on cancer subtype (hormone receptor-positive [HR+], human epidermal growth factor receptor 2-positive [HER2+], and triple-negative breast cancer [TNBC]) and stage (I–II and III). The Andersen Healthcare Utilization model was used as a framework to identify relevant treatment factors/covariates (predisposing, enabling, need). Cochran-Armitage tests were used to examine NAC trends over time and multivariable logistic regression models were used to identify factors related to NAC use.

RESULTS: A total of 8,495 older (72.3±5.2 years) women were included. From 2010 to 2017, the overall NAC rate increased from 11.7% to 32.6%, with significant (p<.0001) increasing trends present in all 6 strata. The increases were more substantial among patients with HER2+ disease or TNBC, compared to HR+ disease. In addition to year of diagnosis, the youngest age category (66-69 years) and a higher cancer stage were associated with a significantly (p<0.05) higher odds of NAC receipt in most strata.

CONCLUSIONS: An increasing trend of NAC use is evident in the Medicare population with stage I–III breast cancer. In more recent years, among chemotherapy-treated patients with stage III HER2+ disease or TNBC, NAC has become more prevalent than AdC only.