Investigating aspirin and post-colonoscopy colorectal cancer and cancer-specific mortality risk: a Swedish Register...

Acetylsalicylic acid (ASA) has been linked to reduced incidence and mortality in colorectal cancer (CRC), although its sex-specific effects remain unclear. Post-colonoscopy colorectal cancer (PCCRC), is a CRC diagnosed after a colonoscopy negative for cancer. The aim of this study was to explore the sex-specific effects of ASA on cancer-specific mortality risk in in CRC in general and in PCCRC specifically.

This retrospective register-based study analyzed the conditional CRC-specific survival in 22 270 Swedish patients who underwent colonoscopy, including 1647 PCCRCs. The analyses were stratified on sex.

ASA use was associated with lower CRC mortality in men but not in women, hazard ratio (HR) = 0.85, 95% confidence interval (CI): 0.72-0.99, P  = 0.043 for men and HR = 1.13, 95% CI: 0.93-1.37, P  = 0.230 for women. Notably, ASA use in women, but not in men, with PCCRC was linked to increased mortality risk; HR for interaction PCCRC × ASA in women = 1.60, 95% CI: 1.02-2.51, P  = 0.040 and HR for interaction PCCRC × ASA in men = 0.81, 95% CI: 0.50-1.32, P  = 0.41.

These exploratory analyses suggest sex-specific differences in the effect of ASA on CRC outcomes, particularly in PCCRC. Further research is needed to elucidate underlying the mechanisms and optimize chemopreventive strategies.