Regular long-term aspirin use may lower the risk of hepatocellular carcinoma (HCC) and ovarian cancer, adding to the growing evidence that aspirin may play a role as a chemopreventive agent, according to two new studies published in JAMA Oncology.
In the first study, led by Tracey G. Simon, MD, of Massachusetts General Hospital, Boston, the authors evaluated the associations between aspirin dose and duration of use and the risk of developing HCC. They conducted a population-based study, with a pooled analysis of two large prospective U.S. cohort studies: the Nurses’ Health Study and the Health Professionals Follow-up Study. The cohort included a total of 133,371 health care professionals who reported long-term data on aspirin use, frequency, dosage, and duration of use.
For the 87,507 female participants, reporting began in 1980, and for the 45,864 men, reporting began in 1986. The mean age for women was 62 years and was 64 years for men at the midpoint of follow-up (1996). Compared with nonaspirin users, those who used aspirin regularly tended to be older, former smokers, and regularly used statins and multivitamins. During the follow-up period, which was more than 26 years, there were 108 incident cases of HCC (65 women, 43 men; 47 with noncirrhotic HCC).
The investigators found that regular aspirin use was associated with a significantly lower HCC risk versus nonregular use (multivariable hazard ratio, 0.51; 95% confidence interval, 0.34-0.77), and estimates were similar for both sexes. Adjustments for regular NSAID use (for example, at least two tablets per week) did not change the data, and results were similar after further adjustment for coffee consumption and adherence to a healthy diet. The benefit also appeared to be dose related, as compared with nonuse, the multivariable-adjusted HR for HCC was 0.87 (95% CI, 0.51-1.48) for up to 1.5 tablets of standard-dose aspirin per week and 0.51 (95% CI, 0.30-0.86) for 1.5-5 tablets per week. The most benefit was for at least five tablets per week (HR, 0.49; 95% CI, 0.28-0.96; P = .006).
“Our findings add to the growing literature suggesting that the chemopreventive effects of aspirin may extend beyond colorectal cancer,” they wrote.
In the second study, Mollie E. Barnard, ScD, of the Harvard School of Public Health, Boston, and her colleagues looked at whether regular aspirin or NSAID use, as well as the patterns of use, were associated with a lower risk of ovarian cancer.
The data used were obtained from 93,664 women in the Nurses’ Health Study (NHS), who were followed up from 1980 to 2014, and 111,834 people in the Nurses’ Health Study II (NHSII), who were followed up from 1989 to 2015. For each type of agent, including aspirin, low-dose aspirin, nonaspirin NSAIDs, and acetaminophen, they evaluated the timing, duration, frequency, and number of tablets that were used. The mean age of participants in the NHS at baseline was 45.9 years and 34.2 years in the NHSII.
There were 1,054 incident cases of epithelial ovarian cancer identified during the study period. The authors did not detect any significant associations between aspirin and ovarian cancer risk when current users and nonusers were compared, regardless of dose (HR, 0.99; 95% CI, 0.83-1.19). But when low-dose (less than or equal to 100 mg) and standard-dose (325 mg) aspirin were analyzed separately, an inverse association for low-dose aspirin (HR, 0.77; 95% CI, 0.61-0.96) was observed. However, there was no association for standard-dose aspirin (HR, 1.17; 95% CI, 0.92-1.49).
In contrast, use of nonaspirin NSAIDs was positively associated with a higher risk of ovarian cancer when compared with nonuse (HR, 1.19; 95% CI, 1.00-1.41), and there were significant positive trends for duration of use (P = .02) and cumulative average tablets per week (P = .03). No clear associations were identified for acetaminophen use.
“Our results also suggest an increased risk of ovarian cancer among long-term, high-quantity users of nonaspirin analgesics, although this finding may reflect unmeasured confounding,” wrote Dr. Barnard and her coauthors. “Further exploration is warranted to evaluate the mechanisms by which heavy use of aspirin, nonaspirin NSAIDs, and acetaminophen may contribute to the development of ovarian cancer and to replicate our findings.”
The ovarian cancer study was supported by awards from the National Institutes of Health. Dr. Barnard was supported by awards from the National Cancer Institute, and her coauthors had no disclosures to report. The HCC study was funded by an infrastructure grant from the Nurses’ Health Study, an infrastructure grant from the Health Professionals Follow-up Study, and NIH grants to several of the authors. Dr. Chan has previously served as a consultant for Bayer on work unrelated to this article. No other disclosures were reported.
SOURCES: Barnard ME et al. JAMA Oncol. 2018 Oct 4. doi: 10.1001/jamaoncol.2018.4149; Simon TG et al. JAMA Oncol. 2018 Oct 4. doi: 10.1001/jamaoncol.2018.4154.