SAN ANTONIO, Dec. 9 (UPI) -- Researchers found no link between taking aspirin and improved breast cancer outcomes, however the drug's effect on breast density may help with earlier diagnosis, according to two new studies presented at a conference on breast cancer.
Researchers from the University of Pennsylvania presented the new studies at the San Antonio Breast Cancer Symposium.
"Past studies have found that aspirin may hold anti-cancer benefits. However, many of them were preliminary, preclinical, and didn't support a clear mortality benefit. They also didn't look at prior use of aspirin," said Dr. Julia Tchou, an associate professor of surgery at the University of Pennsylvania, in a press release. "Our data did not support the notion that this century-old pill has protective qualities and down-the-road benefits for breast cancer patients. However, larger patient cohort studies are needed to confirm our results."
In what they said was the first large review of patient data from a single institution on aspirin's effects on breast cancers, researchers reviewed patterns of aspirin use, cancer pathology, and overall survival for more than 1,000 patients at the Abramson Cancer Center at the University of Pennsylvania.
About 14 percent of patients had been using aspirin for at least 30 days before diagnosis, and aspirin use generally was associated with being older than age 50. Patient data revealed use of aspirin was associated with poorer outcomes and worse overall survival, even when considering individual cancer and health conditions.
The other study looked at the effect of daily aspirin use on breast density in 26,000 women, which is a risk factor for estrogen receptor-related breast cancers and can hinder diagnosis.
Of the women in the study, whose mean age was 57.3, 19.7 percent reported current aspirin use. Overall, aspirin users were older and had higher BMI. The researchers found that, in addition to the drug lowering breast density, the higher the regular dose of aspirin, the lower density breasts women had.
In both studies, the researchers noted that aspirin users were more likely to be older, and to be African-American. They also said larger, randomized and controlled studies need to be done for better measures of aspirin's effects on breast cancers, which some researchers said about studies on the drug in 2005.
Researchers in England recently started what they said is the first such study, for which they plan to recruit 11,000 participants being treated for bowel, breast, esophageal, prostate or stomach cancers. The study may run as long as 12 years because researchers plan to follow the participants for five years.
"If we find that aspirin does stop these cancers returning, it could change future treatment -- providing a cheap and simple way to help stop cancer coming back and helping more people survive," Dr. Ruth Langley, a professor at University College London, which is conducting the study, said in October.