According to a prospective study presented at the annual meeting of the American Association for Cancer Research, regular, long-term aspirin use is associated with a reduced risk of cancer, especially in gastrointestinal tract tumors. Medical Pulse compiled the following: Although previous studies have suggested that taking aspirin daily may reduce the overall risk of cancer, in the context of the study, data from the Women’s Health Study confirmed that taking aspirin once every other day, at low doses, only reduces the risk of colorectal cancer. “Previous studies on the relationship between aspirin and cancer have been limited by their study size, length of follow-up, or ability to make sense of aspirin use under the influence of other lifestyle factors,” Yin Cao (a researcher in the Department of Nutrition at the Harvard School of Public Health) noted in a press release. “Our study provides key information on the potential benefits of taking aspirin in terms of dose, timing, and duration for a large number of individuals.” The study included 82,600 female nurses and 47,651 male health professionals enrolled in the 1980 Nurses’ Health Study and the 1986 Health Professionals Follow-Up Study, respectively. Researchers collected data every two years on aspirin use, risk factors and cancer diagnoses. After 32 years of follow-up, 27,985 people developed cancer (20,414 of whom were women). Participants who took more than two aspirin tablets per week had a 5% reduction in overall cancer risk (RR=0.95; 95% CI, 0.93 to 0.98). The risk reduction was mainly in the form of lower incidence of gastrointestinal tumors (HR=0.8; 95% CI, 0.75 to 0.85), including colorectal cancer (HR=0.75; 95% CI, 0.69 to 0.81) and gastroesophageal cancer (HR=0.86; 95% CI, 0.71 to 1.04). Regular aspirin users did not have a reduced risk of non-gastrointestinal cancers (HR=0.98; 95% CI, 0.96 to 1.01), and the researchers noted that taking aspirin was not associated with a reduced risk of breast cancer, advanced prostate cancer, or lung cancer. The overall benefit of taking aspirin in terms of cancer risk was dose-dependent (P<0.001). Compared with participants who did not take aspirin, those taking aspirin 0.5 to 1.5 tablets per week (RR=0.99; 95% CI, 0.95 to 1.03), 2 to 5 tablets per week (RR=0.97; 95% CI, 0.93 to 1.01), 6 to 14 tablets per week (RR=0.93; 95% CI, 0.89 to 0.97), and 15 or more tablets per week ( RR=0.94; 95% CI, 0.87 to 1) for participants with a correspondingly lower risk. However, the researchers reported not finding a statistically significant reduction in risk before taking aspirin for 16 years (P=0.001). In addition, participants no longer showed a statistically significant reduction in cancer risk 4 years after they stopped taking aspirin regularly. The researchers found no differences between aspirin use and cancer risk by gender, race or ethnicity, cancer, or family history of diabetes, body mass index, smoking history, or regular use of NSAIDs, or multivitamin tablets.