Regular use of aspirin at specific doses appeared to decreased risk for ovarian cancer and hepatocellular carcinoma, according to two separate studies of health professionals.
Use of nonaspirin NSAIDs did not decrease the risk for HCC and appeared to increase the risk for ovarian cancer.
Studies have shown aspirin may reduce the risk for colorectal cancer. In 2015, the U.S. Preventive Services Task Force recommended aspirin use be considered for the prevention of colorectal cancer in individuals aged 50 to 69 years with specific cardiovascular risk profiles.
However, questions remain about aspirin’s effectiveness in preventing other types of cancer and regarding the appropriate dose and frequency for prevention. Evidence for cancer prevention has been mixed within the fields of ovarian cancer and HCC.
Barnard, a postdoctoral fellow at Huntsman Cancer Institute at The University of Utah, and colleagues used data from the Nurses’ Health Study (n = 93,664; mean age at baseline, 45.9 years; 93% non-Hispanic white) — followed from 1980 to 2014 — and Nurses’ Health Study II (n = 111,834; mean age at baseline, 34.2 years; 92% non-Hispanic white), followed from 1989 to 2015, to examine the impact of anti-inflammatory drugs on ovarian cancer risk.
The study included data on use of aspirin — including low dose (100 mg) and standard dose (325 mg) — and nonaspirin NSAIDs. Researchers defined regular use as at least two doses per week.
Among both cohorts, researchers observed 1,054 cases of epithelial ovarian cancer.
Low-dose aspirin taken regularly appeared associated with a 23% lower risk for ovarian cancer (HR = 0.77; 95% CI, 0.61-0.96) compared with nonuse. However, aspirin use at the standard dose did not appear to decrease the risk for ovarian cancer (HR = 1.17; 95% CI, 0.92-1.49).
Researchers did not observe an association between ovarian cancer and aspirin use when current use of any-dose aspirin was compared with nonuse (HR = 0.99; 95% CI, 0.83-1.19).
“What really differentiated this study from prior work was that we were able to analyze low-dose aspirin separately from standard dose aspirin,” Barnard said in a press release. “Our findings emphasize that research on aspirin use and cancer risk must consider aspirin dose. Our results also highlight the need for ongoing conversations between patients and their doctors on the risks and benefits of taking low-dose aspirin.”
Current use of nonaspirin NSAIDs appeared associated with a 19% higher risk for ovarian cancer (HR = 1.19; 95% CI, 1-1.41) compared with nonuse. Researchers also observed trends between ovarian cancer risk and duration of NSAID use (P for trend = .02) and cumulative average tablets per week (P for trend = .03).
“Our findings expand on two consortium studies showing that daily aspirin is related to lower ovarian cancer risk. Many people take a low-dose aspirin daily for heart disease prevention,” Shelley S. Tworoger, PhD, associate center director of population science at Moffitt Cancer Center, said in the release. “More research is needed to figure out which women can benefit most from taking low-dose aspirin to reduce their risk of ovarian cancer.”
In a second study, Tracey G. Simon, MD, research fellow in medicine at Massachusetts General Hospital, and colleagues assessed the impact of daily aspirin on HCC risk using data the from Nurses’ Health Study and the Health Professionals Follow-up Study.
The analysis included 87,507 women (mean age, 62 years) and 45,864 men (mean age, 64 years) with 4,232,188 person-years of follow-up.
Researchers observed 108 cases of HCC over more than 26 years.
Use of two or more 325 mg aspirin tablets per week appeared associated with a 49% reduced risk for HCC (adjusted HR = 0.51; 95% CI, 0.34-0.77). This association appeared to be dose related (P for trend = .006). In a multivariable analysis, HRs compared with nonuse were 0.87 (95% CI, 0.51-1.48) for 1.5 standard-dose tablets per week, 0.51 (95% CI, 0.3-0.86) for 1.5 to 5 tablets per week and 0.49 (95% CI, 0.28-0.96) for more than 5 tablets per week.
Additionally, increasing duration of use appeared to lower HCC risk (P for trend = .03). Use of 1.5 or more standard-dose aspirin tablets per week for 5 years or longer appeared significantly associated with lower risk for HCC (adjusted HR = 0.41; 95% CI, 0.21-0.77).
Nonaspirin NSAID use did not appear to be significantly associated with HCC risk (HR = 1.09; 95% CI, 0.78-1.51).
“The long duration of aspirin use could be necessary because primary liver cancer takes many years to grow. Aspirin may act at the earliest stages of cancer development, or even at precancerous stages, by delaying or preventing inflammation or liver fibrosis,” Simon said in a press release. “While it's still too early know whether starting aspirin therapy might be an effective strategy to prevent HCC, efforts to understand the mechanisms behind these beneficial effects could help identify urgently needed prevention strategies or biomarkers for a cancer that is a growing public health problem.”
In an accompanying editorial, Victoria L. Seewaldt, MD, the Ruth Ziegler professor, chair of department of population sciences, and associate director for population sciences research, at City of Hope Comprehensive Cancer Center, suggested areas for future research.
“The two studies .... have the power to start to change clinical practice; however, there is still much to be learned about the mechanism underlying dose and duration of aspirin use,” she wrote. “Furthermore, as both articles caution, the potential benefits of aspirin must be weighed against the risk of bleeding, particularly in individuals with chronic liver disease. To reach the full promise of aspirin’s ability to prevent cancer, there needs to be better understanding of dose, duration and mechanism.” – by Cassie Homer
Disclosures: Barnard, Tworoger, Simon and Seewaldt report no relevant financial disclosures. One author of the study by Simon and colleagues reports a previous consultant role with Bayer.