Aspirin and cancer risk is in the news again—and the link is still unclear. Two studies published early online in the Journal of Clinical Oncology evaluated the relationship between aspirin and cancer risk—one indicated that aspirin does not appear to reduce the risk of developing breast cancer, while the other found that regular aspirin use was associated with a reduced risk of dying from prostate cancer.
Researchers continue to evaluate the link between cancer risk and aspirin, especially as a growing body of evidence suggests that aspirin may reduce the risk of several types of cancer, with particularly strong evidence for colorectal cancer. Not all studies have found a benefit, however, and any potential benefits of aspirin must be weighed against risks such as bleeding. Current clinical guidelines recommend daily aspirin for some individuals to protect against cardiovascular disease. The data continues to roll in regarding aspirin and cancer.
Researchers from Brigham and Women’s Hospital in Boston used data from a long-term study that included over 100,000 nurses in the United States who completed regular surveys regarding diet, lifestyle, and medication use, as well as any medical diagnoses. The researchers identified 84,600 subjects who were postmenopausal and cancer-free at the beginning of the study in 1980. Between 1980 and 2008, 4,734 women were diagnosed with breast cancer. Based on the data, the researchers found that regular use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) did not appear to reduce the risk of developing breast cancer—even among those who used aspirin daily for more than 10 years.
In the second study, researchers analyzed data from 5,955 men in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) database. All of the men had localized prostate cancer and were treated with surgery or radiation. Over one-third of the men (37%) were taking anticoagulants—most commonly, aspirin. The researchers found that after a median follow-up of 70 months, the risk of death from prostate cancer was significantly lower in the group of men taking aspirin compared to their counterparts. In fact, those taking aspirin were less than half as likely to die from prostate cancer over a 10-year period—the prostate cancer death rate among the men taking aspirin was 3 percent compared to 8 percent among the men who were not. Men taking aspirin were also significantly less likely to experience disease recurrence or cancer spread to the bones. The researchers concluded that regular aspirin use is associated with reduced prostate cancer-specific mortality.
Both studies serve to further shine the light on the relationship between aspirin use and cancer incidence and mortality. Research will likely continue—but for now, it appears that aspirin does not reduce the risk of breast cancer, but may reduce the risk of death from prostate cancer.
 Zhang X, Smith-Warner SA, Collins LC, et al. Use of aspirin, other nonsteroidal anti-inflammatory drugs, and acetaminophen and postmenopausal breast cancer incidence. Journal of Clinical Oncology. Published early online August 27, 2012. doi: 10.1200/JCO.2012.42.2006
 Choe KS, Cowan JE, Chan JM, et al. Aspirin use and the risk of prostate cancer mortality in men treated With prostatectomy or radiotherapy. Journal of Clinical Oncology. Published early online August 27, 2012. doi: 10.1200/JCO.2011.41.0308
Posted September 14, 2012