Real-world clinical outcomes of intermediate-risk PAM50 (i-ROR) in HR+/HER2- early breast cancer and eligibility for adjuvant CDK4/6 inhibitors.
Risk-adapted strategies are central to early breast cancer (EBC) management, particularly in HR+/HER2 - disease. Prosigna/PAM50 combined with clinicopathologic factors refines prognosis, with clearer guidance at ROR extremes, while decisions in the intermediate-risk (i-ROR) group remain challenging. Although adjuvant iCDK4/6 therapy improves outcomes in high-risk patients, eligibility in i-ROR may be overlooked. This study outlines clinicopathologic features, recurrence-free survival, and iCDK4/6 eligibility in i-ROR EBC to support treatment decision-making.
We performed a retrospective analysis of 554 EBC patients who underwent PAM50 testing at Hospital Universitario 12 de Octubre (2015-2024). Clinical, pathological, diagnostic, follow-up, and recurrence data were obtained from records. Kaplan-Meier analyses estimated RFS, while multivariate logistic regression identified predictors of chemotherapy use within i-ROR. Descriptive statistics assessed eligibility for adjuvant ribociclib (NATALEE) and abemaciclib (monarchE).
Among 212 i-ROR patients (38%), 71.7% were postmenopausal, 65.5% Luminal A and 34% Luminal B intrinsic subtypes, and 53.7% node-negative. 68.4% did not receive chemotherapy. There were 11 relapses, predominantly Luminal A (72.7%), node-negative (63.6%), and chemotherapy-naive (90.9%). RFS at 12, 36, and 60 months was 100%, 97.9%, and 96.9%. Chemotherapy use was associated with younger age (p = 0.006), node positivity (p = 0.021), and luminal B subtype (p = 0.001). CDK4/6 eligibility was 44.3% for NATALEE and 14.6% for monarchE, with 10.8% meeting both; chemotherapy use was higher in monarchE-eligible patients (41.9% vs. 31.9%).
This real-world cohort of PAM50 i-ROR HR+/HER2 - EBC patients showed excellent prognosis (5-year RFS > 96%), yet relapses still occurred, highlighting the need for improved risk stratification and consideration of adjuvant therapies, including iCDK4/6.
We performed a retrospective analysis of 554 EBC patients who underwent PAM50 testing at Hospital Universitario 12 de Octubre (2015-2024). Clinical, pathological, diagnostic, follow-up, and recurrence data were obtained from records. Kaplan-Meier analyses estimated RFS, while multivariate logistic regression identified predictors of chemotherapy use within i-ROR. Descriptive statistics assessed eligibility for adjuvant ribociclib (NATALEE) and abemaciclib (monarchE).
Among 212 i-ROR patients (38%), 71.7% were postmenopausal, 65.5% Luminal A and 34% Luminal B intrinsic subtypes, and 53.7% node-negative. 68.4% did not receive chemotherapy. There were 11 relapses, predominantly Luminal A (72.7%), node-negative (63.6%), and chemotherapy-naive (90.9%). RFS at 12, 36, and 60 months was 100%, 97.9%, and 96.9%. Chemotherapy use was associated with younger age (p = 0.006), node positivity (p = 0.021), and luminal B subtype (p = 0.001). CDK4/6 eligibility was 44.3% for NATALEE and 14.6% for monarchE, with 10.8% meeting both; chemotherapy use was higher in monarchE-eligible patients (41.9% vs. 31.9%).
This real-world cohort of PAM50 i-ROR HR+/HER2 - EBC patients showed excellent prognosis (5-year RFS > 96%), yet relapses still occurred, highlighting the need for improved risk stratification and consideration of adjuvant therapies, including iCDK4/6.
Authors
Terán Terán, Illia Illia, Quevedo Quevedo, Moreno Moreno, Bianchi Bianchi, Lema Lema, González González, Tolosa Tolosa, Madariaga Madariaga, Manso Manso, Ruano Ruano, Parrilla Parrilla, Cobos Cobos, Ciruelos Ciruelos, Sánchez-Bayona Sánchez-Bayona
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