WASHINGTON - PRIMARY-CARE doctors perform colonoscopies just as well as specialists, a finding that could help meet the rising need for this important colorectal cancer screening test, US researchers said on Monday.

As populations in the United States and other nations age, the number of people who could benefit from a colonoscopy is outpacing the number of specialists such as gastroenterologists who typically do it, the researchers said.

Dr Thad Wilkins of the Medical College of Georgia and colleagues examined 12 studies published from 1992 to 2006 to assess the quality of colonoscopies performed by primary-care doctors, mostly family medicine doctors and internists, who are more numerous than the specialists.

Based on measures such as the frequency of complications, the amount of the colon examined and rates of detecting cancer and precancerous growths, they found that these colonoscopies were as safe and effective as those done by specialists.

Among other things, Dr Wilkins found a very low complication rate among colonoscopies by primary-care doctors.

The findings suggest that primary-care physicians who are trained in colonoscopy help expand access to colonoscopies, particularly in rural and sparsely populated areas where specialists may be scarce, the researchers said.

A colonoscopy is used to look for signs of cancer in the colon and rectum. A doctor inserts a long, flexible, lighted tube into the rectum and guides it into the colon, checking for abnormalities.

During the procedure, the doctor may remove precancerous growths, preventing the development of cancer, and take tissue samples. The procedure can detect colorectal cancer at early stages when it responds best to treatment.

Last week, a report from colonoscope maker Olympus Corp and The Lewin Group healthcare consulting firm, projected a shortfall of more than 1,000 gastroenterologists by 2020.

Dr Wilkins said the study looked at colonoscopies done by primary-care doctors who were properly trained to do them.

'So it doesn't apply to all primary-care physicians. And it's probably about 5 per cent or less of primary-care physicians who are trained at colonoscopy,' Dr Wilkins, whose findings appear in the journal Annals of Family Medicine, said in a telephone interview.

The researchers reviewed data on 18,292 patients who had colonoscopies in 10 studies in the United States and two in Canada.

The American Cancer Society recommends that beginning at age 50, men and women should get a colonoscopy every 10 years or another colorectal screening test such as the similar flexible sigmoidoscopy every five years.

But fewer than a third of those who are advised to get a colonoscopy actually have the screening procedure. -- REUTERS