Prognosis and Biological Characteristics of ER-Low Metastatic Breast Cancer: Results from a Multicenter Cohort and the TONIC Trial.

ABSTRACT:

Purpose

The purpose of this study was to assess prognosis of estrogen receptor (ER)-low expression and its dynamics in HER2- metastatic breast cancer and to compare sensitivity to nivolumab between ER-low and triple-negative breast cancer (TNBC).

Experimental design

Two cohorts were analyzed: a multicenter cohort of 982 patients with HER2- metastatic breast cancer and one prospective cohort of 110 patients with ER <10%/HER2- metastatic breast cancer enrolled in the TONIC trial (testing nivolumab). Endpoints were overall survival (OS) and post-relapse survival (PRS) in the retrospective cohort and progression-free survival, OS, and clinical benefit rate in the TONIC trial.

Results

A total of 7.3% of retrospective cases had ER-low breast cancer, 15 of 110 of the TONIC t

SUBMITTER: Miglietta F 

PROVIDER: S-EPMC12703355 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature