Real-world chemotherapy use and survival outcomes in postmenopausal HR+/HER2-breast cancer with low genomic risk (RS ≤ 25): a multicenter cohort study from China.

The RxPONDER trial established that adjuvant chemotherapy does not confer survival benefit in postmenopausal women with hormone receptor-positive (HR+)/HER2-negative breast cancer, 1-3 positive lymph nodes, and a low 21-gene Recurrence Score (RS ≤ 25). Whether these findings have been adopted in routine clinical practice in Asian populations remains unclear. We conducted a multicentre retrospective cohort study of postmenopausal Chinese patients with HR+/HER2-breast cancer and limited nodal involvement who underwent surgical treatment and Oncotype DX testing between 2017 and 2023. Among 385 eligible patients, 54.8% had an RS ≤ 25, yet 46.4% of this low-genomic-risk group received adjuvant chemotherapy. Chemotherapy use declined substantially following publication of RxPONDER, indicating a marked shift in treatment patterns. Importantly, no disease-free survival (DFS) benefit was observed with chemotherapy in patients with RS ≤ 25. Multivariable analyses revealed that higher nodal burden, high histologic grade, and low progesterone receptor expression independently influenced chemotherapy decision-making despite low genomic risk. These real-world data provide supportive evidence consistent with the RxPONDER findings in a Chinese population; however, given the relatively short follow-up duration, longer-term outcomes are warranted to further substantiate these observations.