Real World Data for CDK 4/6 Inhibitor Evaluation in ER+ HER2- High Risk Early Breast Cancer

Despite adjuvant endocrine treatment (AET) advances, hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2−), node-positive early breast cancer (EBC) is associated with a considerable (∼20%) risk of recurrence. We conducted a retrospective study to describe demographic/clinical characteristics and outcomes alongside treatment patterns in patients (pts) with HR+, HER2− node-positive EBC in the region of Scotland served by the Edinburgh Cancer Centre, a specialist referral centre.

National Health Service Lothian data sources were utilized. Included were all adult pts diagnosed with HR+, HER2− node-positive EBC between 1/1/05–31/12/20, commencing AET within 16 months of definitive surgery, with follow-up until 1/8/21; pts treated with abemaciclib within the monarchE trial were excluded. Analysis focused on pts with high risk factors (hRisk), i.e., ≥4 pathologically positive ipsilateral axillary lymph nodes (pALNs) or 1–3 pALNs plus either tumour size ≥5cm and/or histological grade 3 (G3), in line with high risk factors for most (91%) of the pts in the monarchE trial.

Overall, 4600 pts were identified (hRisk n=1498, 33%). In the hRisk group, 16% received neoadjuvant chemotherapy, 66% adjuvant chemotherapy and 92% radiotherapy; AET mostly involved letrozole (34%). For pts with 1-3 pALNs, 5-year Invasive Disease-Free Survival (IDFS) and Overall Survival (OS) were adversely affected by hRisk status (tumour ≥5cm and/or G3) and were similar to the 5-year IDFS and OS of pts with 4-9 pALNs. For pts with hRisk disease, both IDFS and OS were adversely affected by postmenopausal status and ≥10 pALNs (Table).

Real world data from the Lothian region of Scotland confirm that a considerable proportion of HR+, HER2− node-positive EBC represents hRisk disease associated with poor outcomes, pointing to a need for improved treatments. Table: 77P

IDFS and OS in hRisk group (baseline)

 3y IDFS %5y IDFS %3y OS %5y OS %
Overall (n=1498)87769181
No of pALNs (n=1125)    
1-3 (n=539)88799282
4-9 (n=393)88779182
≥10 (n=193)79678873
Menopausal status (n=1498)    
Pre/Peri (n=410)90829588
Post (n=1071)85748978

*Tumour ≥5cm and/or G

ESMO Breast 2022 Abstract 77P

Citation: Annals of Oncology (2022) 33 (suppl_3): S148-S164. 10.1016/annonc/annonc889

A real-world population study in early breast cancer to identify patient characteristics, treatment and outcomes in Scotland | OncologyPRO (

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