Aspirin halves genetic risk of colorectal cancer

Aspirin reduces colorectal cancer risk by half in individuals at high genetic risk. Preventive efficacy is prolonged for 10-20 years after treatment with aspirin, said the University of Helsinki in a press release.

The long-term results of an international multi-centre trial, CaPP2, showed that 600mg of aspirin daily reduced colorectal cancer risk by half compared to those on placebo.

Eight hundred and sixty-one genetically susceptible patients were randomised to have either aspirin or placebo for 2–4 years and followed up for 10–20 years. Of those on aspirin, 40 had colorectal cancer, while 58 of those on placebo got colorectal cancer during the follow-up.

“The results are statistically interpreted that aspirin reduced the risk by about 50%, and the efficacy lasted for 10–20 years after taking the medication,” said Professor Jukka-Pekka Mecklin from the University of Jyväskylä and the Central Finland Hospital District.

The finding is similar to what has been observed after large cardiovascular studies performed in general population previously.

“Tens of thousands of patients had aspirin in placebo-controlled trials to prevent cardiovascular events. After reviewing the data afterwards, those on aspirin had significantly less colorectal cancer than those on placebo,” said Mecklin.

The participants of the current study were identified carriers of Lynch Syndrome. They carry a gene that causes a defect in DNA mismatch repair. Lynch syndrome is the most common predisposition for cancer, the prevalence of which is 1:250 in general population. Most are unaware of their genetic condition.

“Lynch Syndrome gene have often cancer at young age, most often in bowel, womb, bladder, ureter or biliary tract. Genetic testing is beneficial to provide surveillance and targeted prevention to those at risk. If there are multiple cancer cases in the family at relatively young age (50-60 years), or some individuals have had several cancers in these organs, the relatives should seek for genetic counselling,” Mecklin advised.

High doses of aspirin may cause bleeding and gastric ulcer, the reason for which the CaPP research group is currently conducting another study with three different doses (of 100mg, 300mg and 600mg daily).

The results of the CaPP2 trial were published in the renowned medical journal The Lancet. One hundred and forty nine participants and researchers from the Central Finland Central Hospital, the University of Jyväskylä, the HUS and the University of Helsinki contributed to the study.