A recent phase 3 trial has evaluated the safety and efficacy of aspirin in the secondary prevention of colorectal cancer. The study, conducted across 66 centres in 11 countries, included 1,587 patients with high-risk colon or rectal cancer who had completed standard adjuvant chemotherapy. Participants were randomly assigned to take either 200 mg of aspirin daily or a placebo for three years, followed by a five-year follow-up.
The primary aim of the trial was to assess disease-free survival, with a secondary focus on safety. After a median follow-up of nearly five years, the results showed no significant difference in disease-free survival between the aspirin and placebo groups. The aspirin group had a 5-year disease-free survival rate of 77%, compared to 74.8% for the placebo group, with a hazard ratio of 0.91, indicating no significant benefit from aspirin use (p=0.38).
In terms of safety, adverse events were reported at similar rates in both groups, with 49% of aspirin users and 51% of placebo users experiencing any-grade adverse events. Serious adverse events occurred in 12% of aspirin patients and 14% of placebo patients. Notably, there were fewer heart attacks and stroke-related events in the aspirin group, but slightly more gastrointestinal bleeds.
The study concluded that while aspirin was well-tolerated, it did not significantly improve disease-free survival in colorectal cancer patients, challenging its potential role in secondary prevention.
Helena Bradbury, EMJ
Reference
Chia JWK et al. Aspirin after completion of standard adjuvant therapy for colorectal cancer (ASCOLT): an international, multicentre, phase 3, randomised, double-blind, placebo-controlled trial. Lancet Gastroenterol & Hepatol. 2025;10(3):198-209.
