Abstract 2570: Evaluation of aspirin use with cancer incidence and survival among older adults in the prostate, lung, colorectal, and ovarian cancer screening trial

Many studies have evaluated the long-term benefits of aspirin use, however the association between aspirin use and cancer incidence and survival in older individuals remains uncertain. Additional epidemiologic evidence of this association is necessary to better understand any possible protective effects of aspirin in older adults. We performed a post-hoc retrospective analysis of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, investigating the association of aspirin use with the risk of cancer incidence and survival from bladder, breast, esophageal, gastric, pancreatic, and uterine cancers among individuals age 65 and older. PLCO participants were included in the current study if (1) they were age 65 or over at baseline or survived to at least age 65 after enrollment and (2) had a valid baseline questionnaire with completed aspirin use information. Incident cancers were defined as first cancers diagnosed during cohort follow-up. Follow-up time began at the time of randomization or when the participant turned 65, whichever occurred first, and continued until the date of the cancer diagnosis, participant death, or the end of the study follow-up. Among participants diagnosed with the above incident cancers, the association of aspirin use prior to diagnosis with subsequent cancer-specific survival was evaluated. Follow-up for this analysis began at the time of diagnosis and ended at death or end of study follow-up. A total of 154,897 individuals were enrolled in the PLCO Trial. Of these, 139,896 individuals (mean [SD] age at baseline, 66.4 [2.4] years; 71,884 [51.4%] women; 123,824 white non-Hispanic [88.5%]) were included in the current analysis. During the study period, 32,580 incident cancers (including 1,751 bladder, 4,552 breast, 332 esophageal, 397 gastric, 878 pancreatic, 716 uterine cancers) were reported. Neither any aspirin nor aspirin use ≥3 times/week was associated with incidence of any of the investigated cancer types. However, multivariable regression analyses demonstrated that aspirin use ≥3 times/week was associated with increased bladder (HR, 0.67; 95% CI, 0.51-0.88) and breast (HR, 0.75; 95% CI, 0.59-0.96), but not esophageal, gastric, pancreatic, or uterine, cancer-specific survival. A similar association with bladder (HR, 0.75; 95% CI, 0.58, 0.98) and breast (HR, 0.79; 95% CI, 0.63, 0.99) cancer survival was observed with any aspirin use. In conclusion, any aspirin use and aspirin use ≥3 times/week was associated with improved bladder and breast cancer survival. The results of the current study provide suggestive observational evidence of the potential of aspirin use to improve bladder and breast cancer survival, however additional, follow-up studies are warranted. Citation Format: Holli A. Loomans-Kropp, Paul Pinsky, Asad Umar. Evaluation of aspirin use with cancer incidence and survival among older adults in the prostate, lung, colorectal, and ovarian cancer screening trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2570.