Aspirin and other non-steroidal anti-inflammatory drug use and colorectal cancer survival: a cohort study.

Aspirin has been widely reported to reduce the incidence of colorectal cancer. Recently, a survival benefit after diagnosis has also been suggested. Data regarding such a benefit are to date contradictory. This study examines the effect of non-steroidal anti-inflammatory drug (NSAID) use on mortality in colorectal cancer in a larger patient cohort than previously to further clarify this effect, especially in terms of exposure timing and dosing. A study using the General Practice Research Database assessed whether aspirin or NSAID exposure in the year immediately following diagnosis affected all-cause mortality in a cohort of 13 994 colorectal cancer patients. Cox proportional hazards modelling adjusted for age, gender, smoking, body mass index and comorbidity. Overall mortality was slightly lower in patients treated with aspirin, (hazard ratio (HR)=0.91; 95% confidence interval (CI)=0.82-1.00). This effect was observed only in patients treated with prophylaxis-dose aspirin (HR=0.89, CI=0.80-0.98) and only in patients taking aspirin before diagnosis (HR=0.86, CI=0.76-0.98). Differential effects were observed depending on the time after diagnosis. Up to 5 years, a reduction in mortality was observed for aspirin users (HR=0.83, CI=0.75-0.92), whereas after 10 years there was an increase in mortality (HR=1.94, CI=1.26-2.99). For NSAID use, no significant effect was observed on overall mortality (HR=1.07, CI=0.98-1.15). High-dose NSAID use was associated with a slight increase in mortality (HR=1.41, CI=1.26-1.56). These findings provide further indication that aspirin may be beneficial in reducing mortality in colorectal cancer during the first 5 years. The same cannot be said for other NSAIDs, where a small increase in mortality was observed.