Aspirin doesn’t improve breast cancer outcomes but may decrease density

The anti-inflammatory, anti-platelet salicylate medication known to chemists as acetylsalicylic acid—yes, that’s aspirin—doesn’t fight breast cancer but may make dense breast tissue less dense, aiding early detection in women with that characteristic.

Researchers from Penn Medicine presented two studies leading to these conclusions at the 2015 San Antonio Breast Cancer Symposium in December.

In one study, the team, led by Julia Tchou, MD, PhD, of the University of Pennsylvania, scrutinized the medical records of 26,000 women who were routinely screened by mammography within a recent two-year window and saw a doctor who recorded their medication use.

Compared to women with extremely dense breasts, women with fatty or less dense breasts were more likely to be aspirin users, according to a Penn Medicine news release.

Additionally, the researchers found a lower likelihood of having extremely dense breasts with increasing aspirin dose.

This association was especially strong among women under age 60 and among African-American women.

In another study, the Tchou team examined the pattern of aspirin use, cancer pathology and overall survival in 1,000 patients treated for breast cancers, including receptor positive, HER2- positive and triple negative cancers.

A history of aspirin use for at least 30 days prior to diagnosis was reported in 14 percent of the participants.

The team found that a history of taking aspirin was not associated with improved survival, regardless of receptor status, according to the release.

Indeed, to the contrary, at five-year follow up, low-dose aspirin was significantly associated with worse overall survival compared to patients who didn’t take it before their cancer diagnosis.

“Past studies have found that aspirin may hold anti-cancer benefits,” Tchou said in prepared remarks. “Our data did not support the notion that this century-old pill has protective qualities and down-the-road benefits for breast cancer patients.”

Study co-author Despina Kontos, PhD, stressed that the breast density findings “highlight the potential value for a randomized controlled trial of aspirin as an agent in early detection of breast cancer, particularly for women with naturally dense tissues who may be at an increased risk for certain cancers.”