However, it does not reduce risks of many other cancers, including esophageal, pancreatic, or uterine

Although aspirin use was not associated with any reductions in the risk of developing breast, bladder, esophageal, gastric, pancreatic, or uterine cancers, regular and any-time use was associated with improved survival in older patients with bladder and breast cancers, according to a recent study published in JAMA Network Open. No such association was found with survival in esophageal, gastric, pancreatic, or uterine cancers.

“Due to the recent controversy surrounding aspirin use in older adults (i.e., aged 65 years), we decided to focus our investigation on older participants in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. Recent investigations in the PLCO population have demonstrated several associations between aspirin use and the risk of cancer incidence and survival. Among cancers screened as part of the trial protocol, aspirin use has been associated with significant reductions in risk of colorectal polyps and colorectal cancer; in contrast, there was modest to no association between aspirin use and prostate and ovarian incidence and survival,” wrote PLCO trial researchers Holli A. Loomans-Kropp, PhD, MPH, of the National Cancer Institute, Rockville, MD, and colleagues.

“To our knowledge, no investigations into aspirin use and risk of bladder, breast, esophageal, gastric, pancreatic, or uterine cancers have been conducted in PLCO. With the high frequency of aspirin use, the substantial annual incidence of breast, bladder, and uterine cancers in the United States, and the noted association between aspirin use and gastrointestinal cancers (e.g., esophageal, gastric, pancreatic), we chose to perform a thorough investigation of the association between aspirin use and cancer risk and survival of these cancers in PLCO. We hypothesized that aspirin use would be associated with reduced risk of cancer incidence and increased cancer survival,” they explained.

The original PLCO study enrolled patients aged 55 to 74 years from 10 screening centers who were randomized to treatment with aspirin or control treatment.

To assess the association of aspirin use with the risks of new cancer development and survival in site-specific cancers—bladder, breast, esophagus, gastric, pancreatic, and uterine—Loomans-Kropp and colleagues conducted this post-hoc analysis of data from 139,896 participants of the PLCO trial. All were aged 65 years at baseline or had reached age 65 years of age during follow-up (mean age at baseline: 66.4 years; 51.4% women; 88.5% non-Hispanic White). Participants completed a questionnaire to record their aspirin use.

During the study period (Jan.-June 2020), 32,580 incident cancers occurred as follows:

  • 5.4% bladder cancer.
  • 14.0% breast cancer.
  • 1.0% esophageal cancer.
  • 1.2% gastric cancer.
  • 2.7% pancreatic cancer.
  • 2.2% uterine cancer.

The use of aspirin was not associated with the incidence of any of the above cancer types. Aspirin use at least three times/week was not associated with risks of bladder (HR: 0.99; 95% CI: 0.90-1.10), breast (HR: 0.99; 95% CI: 0.93-1.05), esophageal (HR: 0.88; 95% CI: 0.70-1.11), gastric (HR: 0.84; 95% CI: 0.68-1.04), pancreatic (HR: 0.94; 95% CI, 0.81-1.08), or uterine (HR: 0.90; 95% CI: 0.76-1.06) cancers. Researchers also found no associations between any aspirin use and cancer risk.

Upon multivariable regression analysis, however, Loomans-Kropp and colleagues found that taking aspirin at least three times/week was associated with increased survival in patients with bladder (HR: 0.67; 95% CI: 0.51-0.88) and breast (HR: 0.75; 95% CI: 0.59-0.96) cancers, compared with patients who used aspirin less than three times weekly. This association was not seen in patients with esophageal, gastric, pancreatic, or uterine cancer.

Loomans-Kropp and fellow researchers observed a similar association between any use of aspirin and increased survival in bladder (HR: 0.75; 95% CI: 0.58-0.98) and breast (HR: 0.79; 95% CI: 0.63-0.99) cancers, compared with no aspirin use. Again, this association between aspirin use and survival was not true for esophageal, gastric, pancreatic, or uterine cancers.

Limitations of this study include that it is a secondary analysis, did not control for multiple comparisons, lacked specific aspirin doses, and acknowledged that there were possible fluctuations in patient aspirin use throughout follow-up.

“The results presented here add to the accumulating evidence that aspirin may improve survival for some cancers. Although prior research has been most heavily concentrated in gastrointestinal cancers, our analysis extends the advantages associated with aspirin use to other cancers, such as bladder and breast cancers. However, although aspirin use may confer a cancer protective effect, it remains necessary to consider the harms, as well as the benefits, of long-term aspirin use,” concluded Loomans-Kropp et al.

  1. Aspirin use is not associated with reduced risk of developing breast, bladder, esophageal, gastric, pancreatic, or uterine cancers, according to results from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, but was associated with increased survival in those with bladder and breast cancer.

  2. Be aware that some of the limitations of this study include that it is a secondary analysis, did not control for multiple comparisons, lacked specific aspirin doses, and acknowledged that there were possible fluctuations in patient aspirin use throughout follow-up.

E.C. Meszaros, Contributing Writer, BreakingMED™

Loomans-Kropp reported no conflicts of interest.

Cat ID: 118

Topic ID: 78,118,730,118,22,23,24,25,692,935,192,925