Nonsteroidal anti-inflammatory drugs and risk of lung cancer

Regular aspirin and non-aspirin nonsteroidal anti-inflammatory drug (NSAID) use is associated with a reduced risk of colorectal cancer. The effect of NSAIDs on the risk of other cancers remains unclear. To evaluate whether use of aspirin or other specific NSAIDs protects against lung cancer, we conducted a case-control study nested in a cohort of subjects 40-84 years old in 1995-2004, without a diagnosis of cancer before the study start date, and with at least 2 years of enrollment with a general practitioner providing data to the The Health Improvement Network (THIN) database in the UK. Patients who had a first diagnosis of primary lung cancer during the study period were considered cases. A random sample of 10,000 controls was frequency-matched to the cases for age, sex and calendar year. The index date for exposure definition was 1 year before the date of diagnosis for cases and 1 year before a random date within the study period for controls. Relative risks and 95% confidence intervals were estimated using conditional logistic regression stratified for matching factors. Factors such as smoking, chronic obstructive pulmonary disease, cardiovascular diseases and body mass index were introduced in the model. We identified 4,336 cases with primary incident lung cancer (incidence rate 7.6 per 10,000 person-years). Compared with subjects with no prescription of non-aspirin NSAID prior to the index date, the risk of lung cancer was 0.76 (0.61-0.94) among those who received a prescription the previous year and had a treatment duration of at least 1 year. The corresponding relative risk was 1.15 (0.99-1.34) for aspirin. In conclusion, prescription of non-aspirin NSAIDs for at least 1 year might be associated with a slightly reduced risk of lung cancer. Aspirin was not associated with a risk reduction, perhaps due to residual confounding.