Using low-dose aspirin for 5 to 9 years was associated with modestly reduced relative risk.
Inhibition of cyclooxygenase by aspirin is a plausible explanation for how aspirin could lower risk for lung cancer. Some randomized trials have shown a benefit for long-term, low-dose aspirin use, but epidemiological and cohort studies, especially in women, have shown no benefit. In this Korean study, researchers used a national database to identify nearly 13,000,000 patients for whom information on aspirin use and lung cancer diagnoses was available. Low-dose aspirin use was defined as doses of ≤100 mg daily, at least 2 days per week.
During mean 5-year follow-up, about 63,000 cases of lung cancer were diagnosed. Analyses were adjusted for demographic variables and clinical risk factors. Compared with no aspirin use, long-term, low-dose aspirin use was associated with significantly lower risk for lung cancer; risk reductions were 4%, 6%, and 11% after aspirin use for 5 to 6 years, 7 to 8 years, and 9 years, respectively. In subgroup analyses, similar benefits were reported for older patients (age, ≥65). Relative risk reductions for those younger than 65 were small and not statistically significant.