Funding
Breast Cancer Now
Instituto de Salud Carlos III (ISCIII)
Sociedad Española de Oncología Médica (SEOM)
International Breast Cancer Research Foundation (IBCRF)
Breast Cancer Research Foundation of Alabama (BCRFA)
Susan G. Komen (SGK)
National Cancer Institute (NCI)
United States Department of Health and Human Services
Find out more...Alliance for Clinical Trials in Oncology Foundation (The Alliance for Clinical Trials in Oncology Foundation)
ARTICLE ABSTRACT
We do not yet have validated biomarkers to predict response and outcome within hormone receptor–positive/HER2-positive (HR+/HER2+) breast cancer. The PAM50-based chemo-endocrine score (CES) predicts chemo-endocrine sensitivity in hormone receptor–positive/HER2-negative (HR+/HER2−) breast cancer. Here, we evaluate the relationship of CES with response and survival in HR+/HER2+ breast cancer.
Intrinsic subtype and clinicopathologic data were obtained from seven studies in which patients were treated with HER2-targeted therapy either with endocrine therapy (ET) or with chemotherapy (CTX). CES was evaluated as a continuous variable and categorically from low to high scores [CES-C (chemo-sensitive), CES-U (uncertain), and CES-E (endocrine-sensitive)]. We first analyzed each dataset individually, and then all combined. Multivariable analyses were used to test CES association with pathologic complete response (pCR) and disease-free survival (DFS).
A total of 457 patients were included (112 with ET and 345 with CTX). In the combined cohort, CES-C, CES-U, and CES-E were identified in 60%, 23%, and 17% of the patients, respectively. High CES (i.e., CES-E) was associated with a lower probability of achieving pCR independently of clinical characteristics, therapy, intrinsic subtype, and study (adjusted OR = 0.42; P = 0.016). A total of 295 patients were analyzed for DFS with a median follow-up of 66 months. High CES was also associated with better DFS (adjusted HR, 0.174; P = 0.003) independently of pCR, clinical characteristics and intrinsic subtype. In patients with residual disease, the adjusted DFS HR of CES was 0.160 (P = 0.012).
In HER2+/HR+ breast cancer, CES is useful for predicting chemo-endocrine sensitivity and provides additional prognostication beyond intrinsic subtype and clinicopathologic characteristics.
