To Örebro University

BACKGROUND: The aim of this population-based cohort study was to investigate the impact of neoadjuvant chemotherapy (NACT) compared to adjuvant chemotherapy in prognosis among patients with HR+/HER2 negative breast cancer.

METHOD: This population-based study utilized data from the research database BCBaSe 3.0, based on the Swedish National Quality breast cancer register, including all patients with breast cancer diagnosis in Sweden between 2008 and 2019. Propensity score matching approach was applied. The outcomes of interest consisted of distant-disease free (DDFS), breast-cancer specific (BCSS), and overall survival (OS).

RESULTS: In total, 14 459 patients were included in the study cohort of whom 2086 received NACT. After 1:1 propensity score matching (PSM), 1539 patients in each study group were available for analyses. No statistically significant difference in survival outcomes were observed between patients treated with NACT compared to those treated with adjuvant chemotherapy (Hazard Ratio (HR) for DDFS: 1.20; 95 % CI: 0.80-1.79; HR for BCSS: 1.16; 95 % CI: 0.54-2.49; HR for OS: 1.14; 95 % CI: 0.64-2.05).

CONCLUSION: In this population-based cohort study of patients with HR+/HER2-breast cancer, the use of NACT seems to be comparable to adjuvant chemotherapy in terms of prognosis, although non-inferiority cannot be proven by this study design. Until further evidence suggesting a survival benefit in favor of either treatment is available, NACT can be pursued when surgical-de-escalation is intended.