The findings suggest that GPs should screen CAD patients for colorectal cancer.
Colorectal cancer is now the second most prevalent cancer worldwide, with an estimated one in 20 healthy individuals eventually developing the disease.
For this latest study, the researchers recruited 414 patients with an average age of 63, who had undergone coronary angiography for suspected CAD.
Between November 2004 and June 2006 they underwent colonoscopy.
CAD, which is defined as at least a 50 per cent diameter narrowing in any one of the major coronary arteries, was confirmed in 206 of the participants.
A control group of 207 patients matched for age and gender was also recruited for the study because this was not possible within the CAD negative group.
Among CAD-positive participants, 34 per cent had colorectal neoplasms or advanced lesions.
In those who tested negative for CAD, prevalence was 18 per cent, and in controls, just 9 per cent.
Lead researcher Dr Annie On On Chan, from the department of medicine at the University of Hong Kong, said: 'Both colorectal neoplasm and CAD probably develop through the mechanisms of chronic inflammation which is now recognised as being pivotal in the pathogenesis of atherosclerosis and hence, CAD. Colorectal cancer is also thought to progress though the pathway of inflammation.'
But Surrey GP Dr John Pittard, a member of the Primary Care Cardiovascular Society, warned that there was insufficient evidence to suggest that GPs should screen for colorectal cancer in patients with heart problems.
'It is interesting and should prompt research to investigate any possible link between colorectal cancer and CAD,' he said.
'But you cannot change primary care practice based on just one study.'
European studies are needed, as it is possible that the ethnicity of the Chinese participants might have affected the findings, added Dr Pittard.
34% CAD patients with colorectal cancer.
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