Adjuvant chemotherapy extended OS, DFS in luminal B breast cancer

Issue: October 25, 2014

SAN FRANCISCO — Adjuvant chemotherapy significantly prolonged OS and DFS in patients with luminal B breast cancer regardless of HER-2 and PR status, according to retrospective study results presented at the Breast Cancer Symposium.

Meng Zhao, MD, PhD, of Ohio State University Medical Center, and colleagues evaluated data from 432 patients who were diagnosed with luminal B breast cancer — defined as ER-positive and HER-2–negative with histological grade 3, or ER-positive and HER-2–positive disease — between 1998 and 2005. Forty-one percent (n=179) of the patients had HER-2–positive disease, and 22% (n=93) were PR negative.

Meng Zhao

During a median follow-up of 105 months, 56 patients (13%) experienced recurrence. Median DFS and OS had not yet been reached at the time of the analysis.

Results of a multivariate analysis indicated patients who received adjuvant chemotherapy achieved longer DFS (HR=0.3; P=.034) and OS (HR=0.2; P=.013) than patients who did not.

Researchers observed the benefits associated with adjuvant chemotherapy regardless of HER-2 overexpression (HR=1.65 for DFS; P=.37; HR=1.65 for OS; P=.39) and PR status (HR=1.8 for DFS; P=.37; HR=2.3 for OS; P=.25).

However, patients with HER-2–positive disease who were aged 60 years or older experienced shorter DFS (HR=3.23; P=.017) and OS (HR=3.06; P=.027).

“In patients with luminal B subtype, adjuvant chemotherapy significantly improved OS and DFS irrelevant of HER-2 or PR status,” Zhao and colleagues wrote. “HER-2 positivity was a poor prognostic factor in postmenopausal patients; however, the vast majority of them did not receive adjuvant trastuzumab (Herceptin, Genentech).”

For more information:

Zhao M. Abstract #156. Presented at: Breast Cancer Symposium; Sept. 4-6, 2014; San Francisco.

Disclosures: The researchers report no relevant financial disclosures.