Abstract Background: The optimal use of adjuvant chemotherapy in premenopausal women with early-stage hormone receptor-positive (HR+), HER2-negative (HER2−), node-negative breast cancer and intermediate Oncotype DX recurrence scores remains an area of clinical uncertainty. While prospective trials have provided clearer guidance for postmenopausal women, real-world treatment patterns and decision-making processes among premenopausal patients remain less well defined. Methods: We performed a retrospective analysis using the National Cancer Database (NCDB) to identify premenopausal women (50 years) diagnosed from 2010-2021 with stage I-II, HR+/HER2−, node-negative breast cancer and recurrence scores of 11-25. We examined trends in chemotherapy omission, identified sociodemographic and clinical predictors of omission using multivariate logistic regression, and evaluated survival outcomes using Kaplan-Meier analysis and Cox regression. Results: Among 27, 459 patients, 77. 9% had stage I disease (n=21, 408) and 22. 1% had stage II (n=6, 051). Chemotherapy was administered to 28. 3% (n=7, 773), while 71. 7% (n=19, 686) omitted it. Median age was 42 years among those who received chemotherapy and 44 years among those who did not. Among stage I patients, 24. 2% received chemotherapy; in stage II, 42. 6% received it. Chemotherapy use declined significantly from 35. 4% in 2010 to 23. 6% in 2021 (p 0. 001). Factors associated with chemotherapy omission included age 40-50 (OR 1. 82, p 0. 001), diagnosis in 2014-2017 (OR 1. 45, p 0. 001) or 2018-2021 (OR 1. 58, p 0. 001) compared to 2010-2013, treatment at comprehensive (OR 1. 09, p = 0. 023), academic (OR 1. 13, p = 0. 002), or network centers (OR 1. 11, p = 0. 006) versus community centers, Medicare insurance (OR 1. 81, p 0. 001), higher median income ≥46, 000 (OR 1. 14, p = 0. 002), and higher Charlson-Deyo scores (score 2: OR 1. 23, p = 0. 001; score ≥3: OR 1. 32, p = 0. 012). Conversely, chemotherapy omission was less likely among Black (OR 0. 85, p 0. 001), South Asian (OR 0. 68, p 0. 001), Hispanic (OR 0. 83, p 0. 001), and rural patients (OR 0. 88, p = 0. 005) compared to non-Hispanic White and metropolitan patients, respectively. Five-year overall survival was similar between chemotherapy and no chemotherapy groups (98. 1% vs. 97. 6%, p = 0. 244), with no significant survival benefit in Cox regression (HR 0. 98, 95% CI 0. 89-1. 07, p = 0. 51). Conclusions: Chemotherapy omission has increased over time among node negative premenopausal women with intermediate recurrence scores, yet practice variability remains. In this real-world population where treatment decisions were made by patients and physicians, there did not appear to be a survival benefit associated with chemotherapy. Ongoing prospective studies are further evaluating the safety of chemotherapy omission in premenopausal women with low genomic and higher anatomic risk, including the OFSET Trial (NRG-BR009, NCT05879926). Citation Format: I. Ajjawi, M. Wong, W. Wei, T. Park, J. Du, M. Rozenblit, S. Schellhorn, A. Kahn, N. Casasanta, E. Winer, M. Lustberg. Real-world patterns of chemotherapy use in premenopausal women with node-negative early-stage HR+/HER2− breast cancer and intermediate genomic risk abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32 (4 Suppl): Abstract nr PS3-08-16.
Ajjawi et al. (Tue,) studied this question.