Does 5-Aminosalicylic Acid Prevent Colorectal Cancer in Tumour Necrosis Factor: Treated Ulcerative Colitis? A...

Ulcerative colitis (UC) increases the risk of colorectal cancer (CRC). Although 5-aminosalicylic acid (5-ASA) has long been regarded as chemopreventive, it remains unclear whether 5-ASA therapy still confers this benefit when used concomitantly with tumour necrosis factor (TNF) inhibitors.

We performed a retrospective cohort study using the nationwide Japanese Medical Data Vision database. Patients with UC who initiated TNF inhibitors were followed from the first TNF inhibitor prescription until CRC diagnosis or disenrollment. Concomitant 5-ASA use was defined as prescription within 90 days before or after TNF initiation. Cumulative incidence was compared with Kaplan-Meier curves and the log-rank test; hazard ratios (HRs) were estimated with multivariable Cox regression and inverse probability of treatment weighting (IPTW), adjusting for age, sex, primary sclerosing cholangitis (PSC), diabetes, obesity, immunomodulator use, type of TNF agent, and prior advanced therapy exposure.

Among 9,919 eligible patients, 8,387 (84.6%) received concomitant 5-ASA. During follow-up (median 3.14 years), 161 CRC events occurred: crude incidence 3.67/1,000 person-years (with 5-ASA use) versus 4.58/1,000 person-years (without 5-ASA use) (p = 0.421). Concomitant 5-ASA was not associated with CRC risk (adjusted HR 1.25, 95% CI 0.76-2.04; IPTW-adjusted HR: 1.28, 95% CI: 0.78-2.11). Independent risk factors were older age, male sex, and PSC.

We found no measurable chemopreventive benefit of concomitant 5-ASA in UC patients receiving TNF inhibitors during this treatment phase. Accordingly, 5-ASA need not be prioritised for CRC prevention at this stage. Longer observation is required to clarify any benefit beyond the early years of TNF inhibitors.