GI Specialists Reduce Risk of Cancer after Clear Colonoscopy

After a negative colonoscopy, there is a significantly reduced risk of developing colorectal cancer if the exam was done by a gastroenterologist.

Over 110,000 Ontario residents had complete negative colonoscopies between 1992 and 1997, almost all done in a hospital (86 percent).  In the 15 year follow-up time through 2006, 1,596 patients developed colorectal cancer.

Although the number of colonoscopies performed by an individual doctor didn’t make a difference in the risk of getting colon or rectal cancer, the physician’s specialization did.  Exams performed by gastroenterologists led to significantly fewer diagnoses of colorectal cancer during the follow-up period than tests done by other doctors, including general surgeons, internist, or family physicians.

Among patients who had their colonoscopies done in private offices, specialization didn’t make a difference in colorectal cancer development after a negative test.

Linda Rabeneck, MD, MPH, of the University of Toronto who led the study said,

The overall incidence of colorectal cancer is reduced for at least 10 years following a negative colonoscopy, compared with the general population. However, colorectal cancers do occur in individuals following a negative colonoscopy. For this reason, having extensive formal training matters, especially when procedures are more challenging to perform. We found that among those physicians who perform colonoscopy in the hospital setting, gastroenterologists are more proficient at colonoscopy than other physicians, including general surgeons. This may reflect the considerable formal training in endoscopy that forms part of gastroenterology core training requirements in the U.S. and Canada.

SOURCERabeneck et al., Clinical Gastroenterology and Hepatology, online November 2, 2009.


  1. Stephen Lloyd, MD, PhD says

    This conclusion from an analysis of the large Canadian study must be interpreted with extreme skepticism. Although there was a statistically significant difference in protective benefit for colonoscopies done by gastroenterologists, the true determinant of the benefits are based on the quality of the procedures, not just the credentials. We know from published studies that even within a single group of gastroenterologists there is a 4 to 10 fold difference in adenoma detection rates. The colonoscopists with higher polyp rates are naturally providing their patients with better protection. I suggest we require ALL colonoscopists to publish their ADR (adenoma detection rate) and this would give the consumer (patient) an objective measurement of quality that they can use in appropriately selecting the physician who performs this important screening.

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