Practice patterns of platinum chemotherapy use in a population-based cohort of women with nonmetastatic triple-negative breast cancer.

Abstract

e18590 Background: The use of platinum agents (PT) in neoadjuvant chemotherapy (CTX) for triple negative breast cancer (TNBC) has been debated in research and practice guidelines. In high risk patients, the addition of PT to standard anthracycline and taxane regimens improves pathological complete response without definitive evidence of survival benefit (Korde JCO 2021). Due to PT’s toxicities and unclear benefit in early stage breast cancer, this study aimed to elucidate the real world practice patterns of PT use and overuse in breast cancer patients. Methods: The cohort was defined as women with stage I-III TNBC (ER, PR, and Her2 negative) who received curative intent surgery between 2011-2018. We utilized the Hutchinson Institute for Cancer Outcomes Research (HICOR) database, which links enrollment and claims records from commercial and public health insurance plans with clinical information from Washington state cancer registries (Manohar JACR 2020). We hypothesized there was overuse of PT CTX in this cohort. Overuse was defined as PT use in stage I, in the adjuvant period (NCCN 2020), and in nonstandard CTX regimens (PT use without taxane and anthracycline (NCCN 2020)). Results: Of the 910 women in the cohort, average age was 63, 90% were white, 682 (75%) received CTX, and 36% had commercial insurance, versus 53% with public insurance (Medicare 45%, Medicaid 8%). Of those receiving CTX, 39% received neoadjuvant and 67% adjuvant. Of those receiving CTX, 85 (13%) received PT, and 28 (4%) received PT without anthracycline. Of those receiving PT, 20% had stage I disease, and of those receiving adjuvant CTX, 43 (9%) received PT in the adjuvant period. Conclusions: We found there was overuse and nonstandard use of PT in this real world data. This overuse was demonstrated by the fact that 20% of women receiving PT had low risk stage I disease, and 9% of women receiving adjuvant CTX received PT in the adjuvant period. Additionally, there was nonstandard use, with 4% of women getting CTX receiving PT without anthracycline. Next steps in this research are to evaluate factors influencing overuse and nonstandard use, as well as complication rates with PT use and overuse.[Table: see text]