Low-Dose Aspirin and Prevention of Colorectal Cancer

Findings of recent research suggest that low-dose aspirin use is associated with a lower risk of colorectal cancer (CRC), with a more pronounced effect for longer durations of use.

Researchers conducted a nationwide cohort study in Norway to investigate the relationship between low-dose aspirin use and CRC risk among individuals aged 50 and older. The study spanned from 2004 to 2018 and included data from national registers on drug prescriptions, cancer incidence, and sociodemographic factors. A total of 2,186,390 individuals were included in the analysis, with a median follow-up period of 10.9 years.

During the follow-up, 579,196 participants (26.5%) used low-dose aspirin, and 38,577 (1.8%) were diagnosed with CRC. Using multivariable Cox regression models, the study found that current aspirin use was associated with a reduced risk of CRC compared to never use, with a hazard ratio (HR) of 0.87 (95% CI 0.84–0.90). The protective effect of aspirin was more significant for metastatic CRC (HR 0.79; 95% CI 0.74–0.84) than for regionally advanced (HR 0.89; 95% CI 0.85–0.92) and localized CRC (HR 0.93; 95% CI 0.87–1.00), with a P heterogeneity of 0.001.

There was also a significant trend indicating that longer durations of current aspirin use correlated with a greater reduction in CRC risk: HR 0.91 for those who took aspirin for fewer than 3 years, HR 0.85 for 3 to fewer than 5 years, and HR 0.84 for 5 or more years of use, compared to never use (P trend < 0.001). For past aspirin use, the protective effect diminished over time since last use. The study estimated that aspirin use averted 1073 cases of CRC (95% CI 818–1,338) during the study period.

The investigators concluded that the study highlights the potential of low-dose aspirin as a preventive measure against CRC in older adults.

Reference
Nafisi S, Støer NC, Veierød MB, et al. Low-dose aspirin and prevention of colorectal cancer: evidence from a nationwide registry-based cohort in Norway. Am J Gastroenterol. 2024;119(7):1402-1411. doi:10.14309/ajg.0000000000002695