Low-dose aspirin may prevent CRC development

Using low-dose aspirin appears to reduce the risk of colorectal cancer (CRC) in adults, suggests a study.

A total of 2,186,390 individuals aged 50 years and above were included in the analysis. Of these, 579,196 (26.5 percent) used low-dose aspirin and 38,577 (1.8 percent) had a CRC diagnosis during a median follow-up of 10.9 years.

Current aspirin use correlated with a lower risk of CRC (hazard ratio [HR], 0.87, 95 percent confidence interval [CI], 0.84‒0.90) compared with never use. This association was more evident for metastatic CRC (HR, 0.79, 95 percent CI, 0.74‒0.84) than for regionally advanced (HR, 0.89, 95 percent CI, 0.85‒0.92) and localized CRC (HR, 0.93, 95 percent CI, 0.87‒1.00; p=0.001 for heterogeneity).

In addition, there was a significant trend seen between duration of current aspirin use and CRC risk: <3 years (HR, 0.91, 95 percent CI, 0.86‒0.95), ≥3 years and <5 years (HR, 0.85, 95 percent CI, 0.80‒0.91), and ≥5 years of use (HR, 0.84, 95 percent CI, 0.80‒0.88) relative to never use (p<0.001 for trend).

For past use of aspirin, the HRs were 0.89 (95 percent CI, 0.84‒0.94) for <3 years, 0.90 (95 percent CI, 0.83‒0.99) for ≥3 and <5 years, and 0.98 (95 percent CI, 0.91‒1.06) for ≥5 years since last use compared with never use (p<0.001 for trend).

“We estimated that aspirin use averted 1,073 cases of CRC (95 percent CI, 818–1,338) in the study period,” the researchers said.

This nationwide cohort identified adults aged ≥50 years residing for 6 months or more in Norway in 2004‒2018. Data were obtained from national registers on drug prescriptions, cancer occurrence, and sociodemographic factors.

The researchers used multivariable Cox regression models to estimate the association between low-dose aspirin use and CRC risk. They also calculated the number of CRC potentially averted using low-dose aspirin.