Adjuvant endocrine therapy combined with abemaciclib in monarchE patients with high-risk early breast cancer: disease characteristics and endocrine therapy choice by menopausal status

Objectives MonarchE demonstrated that adjuvant abemaciclib, oral CDK4 & 6 inhibitor+endocrine therapy (ET) significantly improved invasive disease-free survival in HR+, HER2- high-risk early breast cancer (EBC) versus ET-alone. As prescribing practices for ET vary in younger patients, we present disease characteristics and ET choice in premenopausal patients (preM) enrolled in monarchE.

Materials/methods Patients with invasive, resected, HR+, HER2- node-positive, high-risk, EBC were randomly assigned 1:1 to adjuvant ET +/- abemaciclib in monarchE. Disease characteristics, prior chemotherapy, and ET patterns were examined by menopausal status at initial diagnosis: preM and postmenopausal patients (postM). ET choices for preM are further described by age.

Results Of the 5637 patients, 43.5%/56.5% were preM/postM, with an even distribution between both arms. Median age for preM/postM was 44/59 years (y); 31.5% preM were ≤40y.

PreM had larger tumor size (abemaciclib+ET/ET-alone [N=1227/1224]; ≥5cm=21/21%) vs postM (abemaciclib+ET/ET-alone [N=1576/1605]=15/14%). PreM had higher rates of neoadjuvant chemotherapy administration (abemaciclib+ET/ET-alone=42/42%) vs postM (32/32%). Aromatase inhibitor (AI) use was higher in postM (abemaciclib+ET/ET-alone=90/89%) vs preM (43/40%); tamoxifen use was higher in preM (57/59%) vs postM (10/11%).

Among preM, AI use was highest in preM ≤40y in both arms (abemaciclib+ET=49.9%/ET=49.4%) and tamoxifen use was highest in preM >40y to ≤50y in both abemaciclib+ET (60.1%) and ET arms (65.0%).

Summary PreM had larger tumors at baseline and were more likely to have received neoadjuvant chemotherapy, suggesting they may have a higher risk of recurrence than PostM.

Previously presented at ESMO Congress 2021, “FPN (Final Publication Number):153P”, “Shani Paluch-Shimon et al.”-Reused with permission.

Publikationsverlauf

Artikel online veröffentlicht:
11. Oktober 2022