HONG KONG, April 26 (Reuters) - Close relatives of colorectal cancer patients appear to have a higher risk of developing colon tumours, a survey in Hong Kong has found, as doctors made renewed calls for more regular screening.

Colorectal cancer is highest in developed countries such as the United States and Japan and often linked to high-fat diets and obesity. It is a growing problem in affluent places in Asia due to changes in diet and more sedentary lifestyles.

"It may not be due to genetics, it could be environmental. People in the same family may have the same eating habits," said Leung Waikeung, professor of medicine and therapeutics at the Chinese University of Hong Kong.

For the survey, researchers at the Chinese University in Hong Kong performed colonoscopy exams on 269 siblings and children of colorectal cancer patients and found that 27.9 percent of them had adenomas -- benign tumours that could become malignant over time.

Adenomas were detected in 16.4 percent of people in a control group -- close relatives of people with no colorectal cancer and no family history of the disease.

REUTERS