Study Suggests Physicians Conduct Unnecessary Surveillance Colonoscopies: Questions and Answers
The Study
1. What was the goal of this study?*
Researchers conducted this study to determine what gastroenterologists and general surgeons in the United States recommend regarding surveillance for various polyps detected during an initial screening colonoscopy and compare their recommendations to published clinical practice guidelines. The study also was designed to understand the factors that influence physician's use of colorectal cancer surveillance.
2. What were the results of the survey?
According to the study findings, physicians recommended surveillance colonoscopies (see Question 7) at frequencies greater than those recommended by evidence-based medical guidelines for some people. Specifically, when the initial colorectal lesion was a hyperplastic polyp (a benign growth not indicating any future problems with colon cancer) - for which professional society guidelines do not recommend surveillance colonoscopy - 24 percent of gastroenterologists and 54 percent of general surgeons said that they would have performed surveillance colonoscopy; most would have done so at least every five years.
When a single adenomatous polyp had been removed - and guidelines recommend, at most, surveillance colonoscopy every three to five years in this instance - more than half of gastroenterologists and three-quarters of general surgeons would have performed the procedure every three years or more often.
In the case of large or multiple polyps found during initial screening- for which most guidelines recommend surveillance colonoscopy every three to five years - almost one half of gastroenterologists and three-quarters of general surgeons recommended having the procedure more often than once every three years.
This paper examined only the use of follow-up colonoscopies on patients who have had polyps removed; it did not include the use of screening colonoscopies, which are colonoscopies performed to check for initial growths.
3. How was this study performed?
Four hundred twenty-one gastroenterologists and 382 general surgeons from all over the United States received the study survey in the mail. The final study group consisted of all respondents who had either directly performed or supervised the performance of screening colonoscopies; the total numbers were 317 gastroenterologists and 125 general surgeons.
4. What did the survey include?
The survey consisted of 40 questions that asked about the doctors' beliefs, opinions, and practices regarding colorectal screening and surveillance.
5. Was there a difference between the gastroenterologists' responses and the general surgeons' responses?
Yes, while the authors found differences in specialty responses, both groups of physicians reported intensive surveillance practices. However, this study was not designed to contrast the different opinions between these two groups of physicians.
6. What were the limitations of this study?
As this study was based on physicians' self-reported practice patterns, not actual practice history, physicians may overestimate or underestimate their performance of surveillance colonoscopy.
Understanding Colonoscopy and Other Colorectal Screening and Surveillance Techniques
7. What is a colonoscopy? What is surveillance colonoscopy?
Colonoscopy is an examination of the inside of the colon using a thin, lighted tube (called a colonoscope) inserted into the rectum. If abnormal areas are seen, tissue can be removed and examined under a microscope to determine whether disease is present, in a procedure called a biopsy.
Surveillance colonoscopies are performed to periodically examine the colon after a colorectal abnormality, either cancerous or benign, has been detected and removed.
8. What are the current guidelines for colorectal cancer screening and surveillance? Who sets these guidelines?
The NCI does not have its own guidelines for colorectal screening or surveillance. However, the United States Preventive Services Task Force (USPSTF) is the federal government's main resource for colorectal screening recommendations. The USPSTF is an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services.
Private organizations also set guidelines in their areas of expertise. The American Cancer Society (ACS), the American Gastroenterological Association (AGA), and the Gastroenterology Consortium are three of many groups that have guidelines in place for colorectal cancer screening and surveillence.
The USPSTF strongly recommends that clinicians screen men and women 50 years of age or older for colorectal cancer, with any of several methods including fecal occult blood testing, sigmoidoscopy, or colonoscopy. The USPSTF found fair to good evidence that several screening methods are effective in reducing mortality, or deaths, from colorectal cancer. The USPSTF concluded that the benefits from screening substantially outweigh potential harms, but the quality of evidence, magnitude of benefit, and potential harms vary with each method. Specifically, the USPSTF did not find direct evidence that screening colonoscopy is effective in reducing colorectal cancer mortality.
Professional societies' recommendations for surveillence colonoscopy after discovering an adenomatous colon polyp vary. Societies do not recommend follow-up colonoscopies (beyond which might be done for screeing in average-risk persons) if hyperplastic polyps are detected.
9. What other procedures are used for screening and surveillance of colorectal cancer, aside from colonoscopy?
Sigmoidoscopy, also called proctosigmoidoscopy, is the inspection of the lower colon using a thin, lighted tube called a sigmoidoscope. The USPSTF found fair evidence that sigmoidoscopy alone or in combination with fecal occult blood test reduces mortality.
Fecal occult blood test, or FOBT, checks for hidden blood in the stool.
Double-contrast barium enema is a procedure in which X-rays of the colon and rectum are taken after a barium-containing liquid is put into the rectum. Barium is a silver-white metallic compound that outlines the colon and rectum on an X-ray and helps show abnormalities. Air is put into the rectum and colon to further enhance the X-ray. Double-contrast barium enema, like colonoscopy, enables the physician to examine the whole bowel, but it is less sensitive than colonoscopy.
Digital rectal exam, or DRE, is an examination in which a doctor inserts a lubricated, gloved finger into the rectum to feel for abnormalities.
Other technologies: The USPSTF found insufficient evidence that newer screening technologies, such as virtual colonoscopy, are effective in improving health outcomes.
10. Why would conducting unessential colonoscopies be a problem?
Increased use of colonoscopy will increase the waiting time for all patients. This back-up will be particularly problematic in some parts of the United States, where there is already a waiting time of several months. This increased waiting period potentially could endanger higher risk patients.
A colonoscopy, like most medical procedures, is not without side effects or complications, although the complication rate is very low. Individuals with a low risk of colorectal cancer could suffer complications, such as colon perforation, bleeding, or heart attack.
Colonoscopies are expensive and time-consuming, and, if done inappropriately, can place extra burden on both patients and doctors.
11. What are the potential complications of colonoscopy?
The most common side effects are cramping pain and abdominal swelling caused by the air used to inflate the colon during the procedure. This air is expelled shortly after the procedure, and these symptoms generally go away within a few hours after the procedure is completed.
If a biopsy (removal of cells or tissues for examination under a microscope) is performed during the procedure, patients may also note small amounts of blood in the bowel movements after the examination. This may last for a few days.
Though rare, there is potential for the colonoscope to injure the intestinal wall, causing perforation or bleeding. Conducting the procedure and administering medications may be associated with hypotension (low blood pressure) and heart attack.
Although this test is very helpful in finding the cause of many digestive diseases, colon abnormalities can go undetected at times. Factors that can lead to this include the inability to detect the completeness of the patient's bowel preparation before the procedure, the skill of the operator of the colonoscope, and the patient's anatomy.
Patients are given sedating medications when the test is performed to make the test more comfortable. Whenever a medication is given, there is a risk of an allergic reaction or side effect of the medication itself. These IV medications are given under medical supervision, and patients are monitored during the procedure to reduce the risk of medication-related complications.
Important Colorectal Cancer Statistics
12. How many people are estimated to be diagnosed with colorectal cancer in the United
States in 2004? How many people are estimated to die from the disease?
An estimated 146,940 people will be diagnosed with colorectal cancer in the United States in 2004. An estimated 56,730 deaths are expected to occur from the disease, accounting for approximately 10 percent of cancer deaths. Colorectal cancer is the second leading cause of cancer deaths overall, after lung cancer.
13. What is the survival rate for people diagnosed with colorectal cancer?
Colorectal cancer has an overall 5-year survival rate of approximately 63 percent. When colorectal cancer is diagnosed at an early stage, the 5-year relative survival rate is 90 percent. However, only 38 percent of colorectal cancers are detected at this stage. If the cancer has spread to neighboring organs or lymph nodes, the 5-year survival rate decreases to
66 percent, and if there are distant metastases (the cancer has spread to other parts of the body), the 5-year survival rate drops to 9 percent.
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* Mysliwiec PA, Brown ML, Klabunde CN, and Ransohoff DF. "Are physicians overperforming colonoscopy? A national survey of colorectal surveillance after polypectomy", Annals of Internal Medicine, Aug 17, 2004; vol. 141 (4).
To view a press release related to this Q&A, go to http://www.cancer.gov/newscenter/pressreleases/OverperformanceColonoscopy
For more information about cancer, visit the NCI Web site at http://cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Information about the United States Preventive Services Task Force may be viewed at http://www.ahrq.gov/clinic/uspstfix.htm.
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