A new study conducted with a large sample found evidence that low-dose aspirin use may play a role in decreasing the risk of a woman developing breast cancer. The study from the City of Hope Beckman Research Institute was reported recently in the journal Breast Cancer Research.
Previous research has suggested there may be a link between daily aspirin use and lower risk of breast cancer. Few studies have tested the link specifically on certain breast cancer subtypes. Because of that, the goal of this study was to determine the effects of low-dose (children’s) aspirin on the risk of breast cancer overall, along with certain subtypes.
The study used a dose of 81 grams of aspirin to qualify as “low dose.” The researchers studied the data of 57,164 women who were part of the California’s Teachers Study, which has monitored the health of more than 133,000 teachers and administrators in California since 1995. As part of that study, in 2005 the participants completed questionnaires detailing their use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs).
The study looked at overall rates of breast cancer development along with specific subtypes. In January 2013, 1,457 women of the 57,164 had developed invasive breast cancer. Of these, it broke them out into categories of either being positive or negative for hormone receptors and positive or negative human for epidermal growth factor receptor.
Looking at the numbers of women taking low-dose aspirin at least three times weekly, the data show that those women were 16 percent less likely to develop breast cancer compared with women who either didn’t take low-dose aspirin or used it infrequently. The study didn’t account for regular strength aspirin, as that was taken only sporadically for a headache or pain relief.
When the study went into the subtypes, it found that the risk of developing HR-positive (where breast cancer cells possess receptors for the hormones estrogen or progesterone) and HER2-negative (where the breast cancer cells do not contain too many HER2 receptors) breast cancer was 20 percent lower for women who took low-dose aspirin at least three times per week.
Although the study was not designed to pinpoint the mechanisms by which low-dose aspirin may lower the risk of breast cancer, the study’s authors speculated that it might be due to the drug’s anti-inflammatory effects.
The study also noted that since aromatase inhibitors are used to treat estrogen-positive breast cancer, and since aspirin is a weak aromatose inhibitor, that may help explain its protective effect against HR-positive breast cancers.
Overall, the study authors conclude that taking low-dose aspirin at least three times weekly could be effective for the prevention of breast cancer. But they stress further detailed study is needed before any widespread recommendations can be made.