What Does Hormone Receptor Mean in BRCA-Associated BC?

CHICAGO — Being hormone receptor positive is generally a favorable prognostic factor in breast cancer, but that doesn’t seem to be the case in women with BRCA-associated tumors, according to a study presented at the American Society of Clinical Oncology annual meeting.

The conclusion is based on a large international study on how hormone receptor status impacts breast cancer outcomes in young women with germline BRCA pathological variants (PVs).

Overall, “hormone receptor positivity did not seem to have a strong positive prognostic value in young BRCA carriers” with early breast cancer, lead investigator Luca Arecco, MD, an oncology resident at the University of Genoa, Italy, said at the meeting.

Investigators reviewed the records of 4709 women ages 40 years or younger with stage 1-3 BRCA-associated invasive breast cancer treated from 2000 to 2020 at 78 centers in 28 countries across four continents. Median follow-up was about 8 years.

Weaker Prognostic Value in Hormone Receptor Status

They found, in general, that hormone receptor–positive breast cancer appears to be biologically more aggressive in patients with BRCA PVs than in the general breast cancer population, generating outcomes similar to those with hormone receptor-negative BRCA tumors.

Specifically, among patients with germline BRCA PVs, while hormone receptor–positive patients had a higher distant recurrence rate (13.1% vs 9.6%) than hormone receptor–negative patients, 8-year disease free survival (65.8% and 63.4% respectively) and overall survival (a bit under 90% in both groups) were similar.

Hormone receptor–positive patients did have a lower rate of second primary breast cancers (9.1% versus 14.7%).

In the formal write-up of the results published shortly after the meeting in Annals of Oncology, the investigators concluded that “in young BRCA carriers, differences in recurrence pattern and second primary breast cancer among hormone receptor–positive versus negative disease warrant consideration in counseling patients on treatment, follow-up, and risk-reducing surgery.”

The team also found other differences between BRCA-associated breast cancer and sporadic disease. For instance, in the BRCA cohort, luminal A-like breast cancer had a worse long-term prognosis in their BRCA cohort than triple-negative or HER2-positive disease. Luminal A-like tumors are generally considered less aggressive, but in patients with BRCA PVs, “improving neoadjuvant chemotherapy…could be worthwhile,” the investigators said.

Also, although the risk of recurrence for sporadic hormone receptor–negative tumors is highest in the first few years, the team found that the risk in the hormone negative BRCA cohort progressively increased with longer follow-up, driven by the occurrence of second primary breast cancers, especially in patients with BRCA 1 PVs.

Greater Clarity in Prognosis in BRCA-Associated Breast Cancer

Overall, study discussant Lisa A. Carey, MD, a breast cancer specialist at the University of North Carolina at Chapel Hill, said, “we now know much more clearly the issues of prognosis in women who are very young and have germline BRCA-associated breast cancer,” about 12% of newly diagnosed cases.

“Young patients with germline BRCA-associated breast cancers have high relapse and high new primary risks, warranting comprehensive multimodality therapy,” she said.

A bit fewer than half of women in the study were hormone receptor–positive, and they tended to be patients with BRCA 2 PVs. The rest were hormone receptor–negative and tended to have BRCA 1 PVs.

Patients with hormone receptor–positive disease had grade 3 cancers in about 50% of cases, while patients with hormone receptor–negative disease had a grade 3 disease in over 80%.

Hormone receptor–positive patients were more likely to have nodal involvement and undergo mastectomies but less likely to receive chemotherapy than hormone receptor–negative patients. It’s likely that few patients in the review received PARP inhibitors, Dr Carey noted.

Although overall survival at 8 years was similar in both groups, after that point “the prognosis of patients with hormone receptor–positive disease appeared to be worse… This appeared to occur earlier than that described in sporadic disease,” in which the worsening of survival in hormone receptor–positive disease occurs after a follow-up of at least 14-15 years, the investigators noted in their journal report.

The work was funded by the Italian Association for Cancer Research, Institut Jules Bordet, Korea Health Industry Development Institute, Australian National Health and Medical Council, Cancer Australia, US National Institute of Health, and others. Dr Arecco had no disclosures. Dr Carey and other coauthors disclosed research funding, speaker honoraria, and other financial relationships with AstraZeneca, Genentech/Roche, Lilly, and other pharmaceutical companies.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.