Prevention of colorectal cancer in people with Lynch syndrome
- consider daily aspirin, to be taken for more than 2 years, to prevent colorectal cancer in people with Lynch syndrome
People with Lynch syndrome have an increased risk of colorectal cancer, with lifetime risk estimated to be between around 50% to 80%
- the main strategy to prevent colorectal cancer in people with Lynch syndrome has been regular screening with colonoscopy and polypectomy
- aspirin has been suggested as another potential prevention strategy for colorectal cancer
Evidence from a multi-country randomised controlled trial showed that taking 600 mg of aspirin daily for more than 2 years reduces the risk of colorectal cancer in people with Lynch syndrome (1)
- although this was only evident when restricting the analysis to those who actually took aspirin as planned, increasing the uncertainty around the evidence
- an observational study among people with Lynch syndrome also showed a reduced risk of colorectal cancer in people who had taken aspirin (varying self-reported doses) in the long term compared to those who had not
Long-term use of aspirin may slightly increase the risk of bleeding (1)
- however, no increased risk of peptic ulcer, gastrointestinal bleeding or cerebral haemorrhage was observed in the randomised controlled trial, although this might be because of the relatively short follow-up time
Further study evidence has been reported by Burn et al (2):
- a statistically significant reduction in colorectal cancer was reported in the per protocol analysis, including those patients who completed 2 years of the intervention (HR 0.56; 95% CI 0.34-0.91; p=0.019)
- in addition, a legacy effect was identified, whereby patients taking aspirin for a finite duration (mean 25 months) had a sustained reduction in colorectal cancer incidence persisting for 20 years. The authors say that these findings, suggesting only 24 people with Lynch syndrome need to be treated with 600mg/day aspirin to prevent one case of colorectal cancer
- although major bleeding and other adverse events were no more frequent in the aspirin group than placebo, the participants were relatively young (mean 45 years at randomisation).
NICE concluded that ".. Given that the potential benefits are likely to outweigh the potential harms for most people with Lynch syndrome, the committee agreed taking aspirin long term will be appropriate in most, but not all, cases (for example in people with history of peptic ulcers)..."
Notes:
- at the time of publication (January 2020), aspirin does not have a UK marketing authorisation for this indication. The prescriber should follow relevant professional guidance, taking full responsibility for the decision. Informed consent should be obtained and documented. See the General Medical Council's Prescribing guidance: prescribing unlicensed medicines for further information. Commonly used aspirin doses in current practice are 150 mg or 300 mg (1)
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