For women with young-onset breast cancer, presence of a BRCA mutation did not significantly impact survival, according to results of the Prospective Outcomes in Sporadic versus Hereditary breast cancer (POSH) study.
BRCA-positive and BRCA-negative women had similar overall survival at 2 years, 5 years, and 10 years after diagnosis, according to lead author Ellen R. Copson, MD, a senior lecturer in medical oncology in the cancer sciences division, University of Southampton (England) and her study coauthors.
Currently, young women with breast cancer and a BRCA mutation frequently are offered bilateral mastectomy, the authors noted.
The prospective cohort study by Dr. Copson and her colleagues included 2,733 women with breast cancer who were aged 40 years or younger at first diagnosis. Of those patients, 338 (12%) had either a BRCA1 or BRCA2 mutation, according to investigators.
At 2 years after diagnosis, overall survival was 97.0% and 96.6% for BRCA-positive and BRCA-negative patients, respectively, the report said. Similarly, overall survival was 83.8% and 85.0% for the two groups at 5 years after diagnosis, and 73.4% vs. 70.1% at 10 years.
Multivariable analysis accounting for known prognostic factors including ethnicity and body mass index showed there was no significant difference between groups (hazard ratio, 0.96; 95% confidence interval, 0.76-1.22; P = .76), the authors wrote.
Triple-negative breast cancer patients with a BRCA mutation might have a survival advantage in the first few years following diagnosis,compared with non-BRCA carriers, the POSH study also found. Researchers reported a significant difference at 2 years (95% for BRCA-positive vs. 91% for BRCA-negative patients; P = .047), but there was no significant difference between arms at 5 or 10 years.
POSH is believed to be the largest prospective cohort study to compare breast cancer outcomes for patients with BRCA mutations to those with sporadic breast cancer. Previous studies, primarily retrospective, have suggested “better, worse, or similar outcomes” for BRCA-positive versus BRCA-negative patients, the authors wrote. Dr. Copson reported receiving honoraria from Roche, while her coauthors reported honoraria from GSK, Pfizer, AstraZeneca, and Pierre Fabre. Funding for the study was provided by the Wessex Cancer Trust, Cancer Research UK, and Breast Cancer Now.
SOURCE: Copson et al. Lancet Oncol. 2018 Jan 11 doi: 10.1016/S1470-2045(17)30891-4.