117 Risk of Recurrence (ROR) Among Patients With HR+/HER2− Early Breast Cancer (EBC) Involving 1-3 Axillary Lymph Nodes (N1): A Real-World Evaluation

Background

Ribociclib plus an aromatase inhibitor was FDA approved in September 2024 for patients with stage II/III early breast cancer at high risk of recurrence (ROR), including select node (N) 0, all N1, and N2+ disease. Abemaciclib plus endocrine therapy (ET) is indicated for patients with early breast cancer involving 4 or more lymph nodes or N1 disease with grade (G) 3 or tumor size (T) 5 cm or more. This study evaluates ROR in patients with hormone receptor–positive (HR+)/HER2-negative (HER2–) early breast cancer with N1 disease who retrospectively met FDA label criteria for ribociclib and abemaciclib (N1-R/A) vs only ribociclib (N1-R).

Methods

A review of randomly selected medical records of adult patients with stage II/III early breast cancer who started adjuvant ET (January 2012-December 2018) from large US community and academic oncology practices was conducted. Patient demographics, treatments, clinician-determined recurrence, and all-cause death were abstracted (data cutoff: May 2025). ROR end points for N1-R/A (N1, G3, or T ≥5 cm) and N1-R (N1, G<3, and T <5 cm) patients were Kaplan-Meier estimated. Results from 4 practices are described.

Results

Among 1752 patients with stage II/III HR+/HER2− early breast cancer, 796 had N1 disease; of these, 290 (36.4%) had N1-R/A and 506 (63.6%) had N1-R. For N1-R/A and N1-R cohorts, median age at diagnosis was 54 and 57 years. Persistence on ET at 5 years was similar in both groups (N1-R/A, 71.1%; N1-R, 73.4%). More N1-R/A patients received (neo)adjuvant chemotherapy (85.9% vs 64.6%). Invasive disease-free, recurrence-free, and distant disease-free (DDFS) survival showed considerable cumulative ROR in both groups (Table). DDFS at 7 years was similar (N1-R/A, 85.5%; N1-R, 85.9%).

Conclusions

For patients with stage II/III N1 disease, substantial ROR was observed over time, regardless of G or T. This analysis indicates a diminishing difference in risk rate (N1-R/A vs N1-R) beyond 5 years. Strategies to reduce ROR in all patients with stage II/III HR+/HER2− early breast cancer with N1 should be considered, including treatment escalation for all N+ patients.

Previously presented at 2025 ESMO Breast: Razavi P, et al. May 14-17, 2025; Munich, Germany. Poster 211P. Reused with permission.