NEW YORK, Oct 05 (Reuters Health) -- Only about one third of Medicare patients found to have blood in their stool on a colon cancer screening test go on to have proper follow-up testing, according to a new report. This lack of follow up may reduce the effectiveness of the screen, known as the fecal occult blood test (FOBT), researchers say.
The test is used to detect blood in a person's stool, which may signal colon cancer, the second leading cause of cancer deaths in the United States. If the test is positive, guidelines recommend either an examination called a colonoscopy or a combination of two tests, flexible sigmoidoscopy using a lighted instrument to examine the lining of the bowel and a barium enema imaging study.
Studies have shown that screening with FOBT can reduce deaths from colon cancer by as much as 35%, according to Dartmouth University researchers Drs. Jon D. Lurie and H. Gilbert Welch. But it appears that many physicians are not following the recommendations of what to do when a test is positive, they report in the October 6th issue of the Journal of the National Cancer Institute.
Lurie and Welch examined the records of 24,246 people enrolled in Medicare, the federal health insurance program for the elderly, who received FOBT during the first 4 months of 1995. The sample tested positive in a little more than 9% of this group.
However, only one third of patients who had a positive FOBT underwent the recommended follow-up examinations, the investigators report. Many of the others did undergo further testing, but in many cases, these tests have not been shown to be as effective in detecting colon cancer.
"Such a low rate of recommended follow-up would reduce the effectiveness of population screening," the researchers write. "In addition, many people received multiple tests, which would increase the costs of population screening," they continue.
Part of the problem may be that some patients may be reluctant to undergo follow-up tests, which are more uncomfortable than the simple stool sample. In addition, physicians may be hesitant to perform colonoscopy or flexible sigmoidoscopy on unhealthy elderly patients.
"Future work should focus on evaluating the usefulness of different follow-up tests after a positive FOBT, why physicians choose different follow-up tests... and patients' understanding of the downstream consequences of FOBT when they decide whether or not to be screened," Lurie and Welch conclude.
Screening all people at average risk of developing colon cancer is expensive, Dr. John H. Bond, of the University of Minnesota in Minneapolis, notes in an editorial accompanying the study, but failing to detect a curable cancer or prevent cancer may be even more costly, he writes.
"Clearly, a great deal of work remains to be done to educate the public about the impact of colorectal cancer and the value of screening," Bond concludes.
