Oncotype DX Recurrence Score and Germline BRCA Variants in Patients with HR-Positive/HER2-Negative Early Breast Cancer: A Retrospective Observational Study.

INTRODUCTION

The Oncotype DX (ODX) recurrence score (RS) is prognostic and predictive of chemotherapy benefit in patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer. Data on the distribution of germline BRCA1 and/or BRCA2 pathogenic variants (gBRCA PV) by RS are limited. This retrospective, real-world study explored demographics, clinical characteristics, gBRCA testing rates, and gBRCA PV prevalence in HR-positive/HER2-negative stage I-III breast cancer, stratified by RS.

METHODS

Deidentified patient data (from 1 January 2011 to 30 September 2022) from US electronic health records in a nationwide database were used. Patients aged ≥ 18 years with HR-positive/HER2-negative breast cancer and a known ODX RS were included. Demographics, clinical characteristics, and genetic testing rates were compared in patients with low, intermediate, and high tumor RS. gBRCA PV prevalence was compared across categories in patients who underwent genetic testing.

RESULTS

Of 3637 patients (median age: 62 years), 950 (26.1%) had low, 2155 (59.3%) had intermediate, and 532 (14.6%) had high tumor RS. Despite increases in genetic testing over time, gBRCA status was determined in only 31.5% (n = 1147/3637) of patients. Among tested patients, 37/1147 (3.2%) had gBRCA PV; median age was lower in gBRCA PV carriers than in noncarriers (52 versus 56 years; p = 0.034); tumors from gBRCA PV carriers had significantly higher grade (p = 0.002) and median RS (p = 0.001) than tumors from noncarriers; prevalence of gBRCA PV was highest among tested patients with high tumor RS (n = 14/185; 7.6%), but gBRCA PVs were identified among patients with intermediate (n = 19/674; 2.8%) and low (n = 4/288; 1.4%) tumor RS.

CONCLUSIONS

Prevalence of gBRCA PV was highest among patients with high tumor RS, but not negligible in patients with intermediate and low tumor RS. Wider implementation of genetic testing, irrespective of ODX RS, could help optimize the management of patients with HR-positive/HER2-negative early breast cancer.