Aspirin and other nonsteroidal anti-inflammatory drugs and risk of non-hodgkin lymphoma.

Few large prospective studies have examined associations between nonsteroidal anti-inflammatory drug (NSAID) use and non-Hodgkin lymphoma (NHL). We examined the association between NSAID use and NHL incidence among 149,570 participants in the Cancer Prevention Study-II Nutrition cohort. Aspirin and nonaspirin NSAID use were reported at enrollment in 1992 and updated on periodic follow-up questionnaires. During follow-up through 2007, 1,709 incident NHLs were identified. Time-dependent hazard ratios were calculated using extended Cox regression. Compared to no use, current use of 60+ NSAID pills/month (aspirin and nonaspirin NSAIDs combined) was associated with slightly higher NHL incidence (hazard ratio [HR] = 1.26, 95% confidence interval [CI], 1.04-1.53), but no association with frequency of use was observed when NSAID exposure was lagged by approximately 2 years (HR = 1.08, 95% CI, 0.88-1.32). Long duration regular use (current use of 30+ pills/month for ≥5 years) was not associated with NHL incidence (HR = 1.09, 95% CI, 0.91-1.33). In subtype analyses, current use of 60+ NSAID pills/month was associated with follicular lymphoma incidence (HR = 1.87, 95% CI, 1.08-3.24). This association persisted when NSAID exposure was lagged (HR = 1.76, 95% CI, 1.04-2.98) and was similar for aspirin and nonaspirin NSAIDs. The association of current, but not lagged, NSAID use with risk of all NHL could be attributable to use of NSAIDs to relieve symptoms of undiagnosed NHL. However, the association with follicular lymphoma persisted in analyses where NSAID use was lagged and should be investigated further. These findings are particularly important for aspirin as the risks and benefits of prophylactic daily use are weighed.