I would like to congratulate Corley and his colleagues for their seminal work on the association between adenoma detection rate and risk of colorectal cancer, advanced colorectal cancer, and colorectal cancer mortality. The impact of their findings—reported in The New England Journal of Medicine1 and reviewed in this issue of The ASCO Post—is far-reaching in society and brings the debate on quality of colonoscopy screening to center field. Each and every player in the field has a stake in this operation. So let us step back and look at what it takes for colonoscopy to prevent colon cancer.
For colonoscopy to be effective in the prevention of colon cancer prevention, one needs to have a search-and-destroy mindset—screen the colon carefully for both the obvious large polypoid lesions as well as the less obvious subtle flat lesions, and cut the precancerous lesions completely and safely. In order to accomplish this task, all players—the patient, the endoscopist, and the primary care provider—need to perform their assigned tasks well, and programs must be set in place to monitor and maximize the chances of optimal outcome.
‘Wash and Rinse’
From the patient’s perspective, it is critical to prepare the colon well to allow the colonoscopist to detect subtle flat lesions. Residual stool after an incomplete colonoscopy preparation frequently noted after a single overnight-dose colon preparation can hide polyps, flat lesions, and cancer. This could be avoided by splitting the dose of colon preparation: half in the evening before the procedure and the other half on the morning of the procedure, with the last dose 4 hours before the procedure, results in a clean colon for excellent screening.
This is best described to the patient as a “wash and rinse” cycle in a dishwasher that ensures excellent clean out in the majority of patients. We should aim for an excellent preparation, and this method can produce a Boston Bowel Preparation Scale score of 8 to 9 in over 95% of cases.
Search and Destroy
From the colonoscopist’s perspective, it is critical to have a mindset of going on a search mission—taking pains to search for polyps and not going in casually for just another colonoscopy. This can be accomplished by adequate training that allows reaching the cecum in over 95% of cases, carefully scanning the entire wall circumferentially for subtle flat lesions, checking the bends and corners as well as folds for hidden lesions, suctioning puddles of fluid as well as clearing froth in search of submerged lesions, and taking the time to examine the entire colon.
Although various society guidelines suggest a minimum of 6 minutes of withdrawal time for adequate examination, one should not forget that the goal is to screen a particular patient’s colon completely—and take whatever time it takes to get the
job done.
From the colonoscopist’s perspective, it is also critical to remove the lesions completely and safely. Removal of pedunculated polyps (those that look like mushrooms) is easy—all that is required is a simple snare resection. However, removal of flat lesions by the same snare resection can be risky (may precipitate bleeding and perforation) and is incomplete in up to 15% to 30% of cases. Removal of these flat lesions requires additional skills, such as injection of fluid to lift the lesion from the wall, followed by snare resection; one should be prepared to control bleeding and close a perforation if a complication were to occur when removing flat
lesions.
When such skills are not available, patients could be referred to colonoscopy centers of excellence for safe and complete removal of such large flat lesions and avoid unnecessary surgery. Because large lesions are at high risk of progression to malignancy, close follow-up to document complete eradication of the neoplasm at 6 to 12 months after resection is critical.
Choose Well
From the referring physician’s perspective, it is important to safeguard the interests of their patients. Unlike many screening programs involved in cancer prevention (skin, breast, prostate, etc), colon cancer prevention is labor intensive and costly for the patient and family; the patient needs to take time off from work to prepare for the procedure; and family members need to take time off from work to escort the patient back from the procedure. Finally, incomplete screening of the colon is a waste of time and a loss of the opportunity to prevent cancer.
So, how does one choose a colonoscopist to screen the patients? Corley and colleagues’ work offers some insights on how to choose the colonoscopist. Those that screen well and showcase a high adenoma detection rate are likely to have less interval colorectal cancers in their patients.
The three major GI societies identified adenoma detection rate as an important quality metric and recommended it as a physician quality reporting system metric to the Centers for Medicare & Medicaid Services. It is time to request adenoma detection rates from your local colonoscopists and use the data to refer to those with an excellent track record. Although patients prefer colonoscopists who offer efficient and on-time service, with free parking and other perks, it is time to educate everyone about the importance of adenoma detection rate and high-quality colonoscopy screening in colon cancer prevention. ■
Disclosure: Dr. Raju reported no potential conflicts of interest.
Reference
1. Corley DA, Jensen CD, Marks AR, et al: Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 370:1298-1306, 2014.
Dr. Raju is Professor of Medicine, Department of Gastroenterology, Hepatology, and Nutrition, University of Texas MD Anderson Cancer Center, Houston.
