After a normal colonoscopy when no polyps are found, guidelines call for a repeat test in 10 years.
However, almost half of Medicare patients with a negative colonoscopy got another exam within 7 years, and for one in four there was no clear evidence that they needed one.
Because colonoscopies have real risks and are expensive, over-testing can be both dangerous and costly. Given limited numbers of physicians who do colonoscopies, unecessary procedures add to long waiting lists for screening and for necessary follow-up exams.
Although Medicare regulations call for reimbursement only after 10 years in cases where the first procedure didn’t find a problem, payments are being made for earlier exams. In fact, Medicare denied payment for only 2 percent of colonoscopies for which there was no clear indication of need.
Researchers at the University of Texas in Galveston reviewed a representative sample of Medicare claims for a colonoscopy between 2001 and 2003. Since they were looking for average risk patients who had a negative screening colonoscopy, they filtered out any tests that included removing a polyp or a biopsy or other procedure done during the exam. They also removed any colonoscopies that included a diagnosis such as bleeding or pain and any that were done for patients who had a Medicare claim in the previous 3 months that included a diagnosis or symptoms of colorectal disease that might have indicated need for a diagnostic colonoscopy.
In their sample of 5% of the Medicare population:
- 236,145 Medicare patients 66 and older had a colonoscopy in 2001-2003.
- 114,468 had an negative exam with no polyps removed, no biopsies or other procedure.
- 24,071 had a negative screening colonoscopy after all possible medical reasons for doing the test were eliminated.
The research team then looked for repeated colonoscopies within 5 and 7 years of the first test. Again they eliminated any exams for which a diagnosis or other Medicare claims indicated a good reason to repeat the test. If they couldn’t find a reason, they classified the colonoscopy as repeated with no clear indication.
In their sample of 24,071 who had a completely negative screening colonoscopy between 2001 and 2003, 8,608 had another colonoscopy within 7 years, and for 3,656 no reason other than routine screening could be found for doing the test.
However, only 86 patients (2 percent) actually had payment denied by Medicare.
Although the US Preventive Services Task Force recommends against routine screening for people between age 75 and 84 and against any screening for those over 85, one third of patients who were 80 or older at their initial negative screening colonoscopy had another exam within 7 years.
The study authors pointed out,
This is of special concern, given the increased potential for complications and decreased benefit of this examination in the very old.
Repeating a colonoscopy early after a negative exam was more likely to occur when:
- Endoscopist doing the first colonoscopy did more than 1,200 procedures a year.
- Exam took place in a doctor’s office rather than hospital or ambulatory surgical center.
- Patients were male.
- Exam took place in the Middle Atlantic or North Central regions of the United States.
- Patients had less than a high school education.
For average risk patients without a family history of inherited colorectal cancer, the natural development of cancer from even quite large polyps is slow. Before the era of colonoscopy, doctors at the Mayo Clinic followed 226 patients who had barium enemas with advanced adenomas (over 1 cm) for 5, 10, and even 20 years. During that time only 2.5% became cancer at 5 years and 8% at 10 years. Seven out of ten cancers were found at an early stage before spreading to lymph nodes or distant sites.
After analyzing their results, James Goodwin, MD, and his colleagues at the University of Texas concluded,
A large proportion of Medicare patients who undergo screening colonoscopy do so more frequently than recommended. Current Medicare regulations intending to limit reimbursement for screening colonoscopy to every 10 years would not appear to be effective.
What This Means for Patients
Although the research was done in Medicare patients over 65, there is no reason to believe that younger patients are not also being screened more often than guidelines call for for.
- After your screening colonoscopy, be sure that you have a copy of the the results that describe if adenomas (polyps) were found and what their size and description was. If you don’t understand the report, ask your doctor to explain it.
- Check to see if the recommendation for the next screening exam fits within the guidelines for colorectal cancer screening. If the return recommendation is sooner that guidelines call for, ask why!
For people at average risk of colorectal cancer, colonoscopy screening is recommended beginning at age 50 and then every 10 years unless adenomas or cancer are found.
The US Preventive Services Task Force says that elderly people between 75 and 84 should not be routinely screened for colorectal cancer and those over 85 should not be screened at all. If your older relative is getting colonoscopy recommendation that don’t fit the guidelines, ask why. They are at higher risk for complications from the procedure and may well not benefit from screening.
- Symptoms of colorectal cancer at any time – even after a negative screening colonoscopy — and at any age call for diagnostic colonoscopy.
- People with a family history of colorectal cancer or a personal medical history of cancer, adenomas, or inflammatory bowel disease (ulcerative colitis or Crohn’s disease) are not at average risk. They should follow screening and surveillance programs for increased and high risk, including beginning earlier than 50 and being screened more often.