NEW ORLEANS — Fecal occult blood testing was ineffective at selecting people with an increased risk of colorectal adenomas or cancer, based on a review of 147 people who had follow-up colonoscopy.
“Fecal occult blood testing did not appear to select for people with colonic neoplasia and should be replaced by alternative screening methods,” Christopher M. Mathews, M.D., said at the southern regional meeting of the American Federation for Medical Research.
His study used data collected by Clinical Outcomes Research Initiative, a database created by the American Society for Gastrointestinal Endoscopy. Using this database, Dr. Mathews and his associates identified 663 people who underwent colonoscopy during 1999–2004 following a positive result on a fecal occult blood test.
They then cross-referenced this list with the patient record system of Veterans Affairs. They found that 147 of the 663 people screened had VA records and were further identified as being asymptomatic at the time of colonoscopy with no history of colorectal cancer or polyps.
All 147 people were men, and 69% were white; 67% were at least 60 years old.
Among the 48 men younger than 60, 44% were found to have colorectal adenomas by colonoscopy, and none had colorectal cancer. Among the 99 men aged 60 or older, 45% had colorectal adenomas, and 4% had colorectal cancer. Overall, there was a 45% prevalence of adenomas and a 2.7% prevalence of colorectal cancer, said Dr. Mathews, a gastroenterologist at the VA Medical Center in Memphis.
These prevalence rates were compared with the rates in an unselected, general population, as documented in two independent autopsy studies. In an autopsy study done in the United States in 1978, the prevalence of colorectal adenomas was 47%, and the prevalence of colorectal cancer was 3.7%. In an autopsy study done in the United Kingdom in 1982, the prevalence of adenomas was 33%, and the prevalence of colorectal cancer was 2.2%.
The comparison showed that the prevalence of colorectal neoplasia in asymptomatic, average risk men who had positive results on fecal occult blood tests was not appreciably different from the prevalence seen during autopsy in an unselected population, Dr. Mathews said.