Effect of anti-inflammatory drugs on overall risk of common cancer: case-control study in general practice research database

Objective To examine whether anti-inflammatory drug treatment protects agai nst the commoner cancers in the United Kingdom. Design Case-control study using the general practice research database. Setting Practices throughout United Kingdom providing data to the database. Subjects Patients who had a first diagnosis of five gastrointestinal (oesop hagus, stomach, colon, rectum, and pancreas) cancers and four non-gastroint estinal (bladder, breast, lung, and prostate) cancers in 1993-5 for whom pr escription data were available for the at least the previous 36 months. Eac h case was matched for age, sex, and general practice with three controls. Main outcome measure Risk of cancer. Results In 12 174 cancer cases and 34 934 controls overall risk of the nine cancers was not significantly reduced among those who had received at leas t seven prescriptions in the 13-36 months before cancer diagnosis (odds rat io 0.98, 95% confidence interval 0.89 to 1.07). Findings were nevertheless compatible with protective effects from anti-inflammatory drugs against can cers of the oesophagus (0.64, 0.41 to 0.98), stomach (0.51, 0.33 to 0.79), colon (0.76, 0.58 to 1.00), and rectum (0.75, 0.49 to 1.14) with dose relat ed trends. The risk of pancreatic cancer (1.49, 1.02 to 2.18) and prostatic cancer (1.33, 1.07 to 1.64) was increased among patients who had received at least seven prescriptions, but the trend was dose related for only pancr eatic cancer. Conclusions Anti-inflammatory drugs may protect against oesophageal and gas tric cancer as well as colon and rectal cancer. The increased risks of panc reatic and prostatic cancer could be due to chance or to undetected biases and wan-ant further investigation.