SAN DIEGO – An optimized colonoscopy method dramatically reduces colorectal cancer diagnoses and deaths, finds a study reported at the annual meeting of the American College of Gastroenterology.
Dr. Sudha Xirasagar of the University of South Carolina in Columbia, reported the experience of the Community Endoscopy Group in using an optimized colonoscopy protocol that includes enhanced efforts, through staffing and protocol modifications, to ensure adequate bowel preparation and polyp identification and removal.
With a follow-up of nearly 5 years, the rate of colorectal cancer in the more than 16,000 patients screened was reduced by 83% and the rate of colorectal cancer mortality was reduced by 89%, relative to what was expected based on data for the general population.
Dr. Sudha Xirasagar
"This study documents the highest-ever colorectal cancer incidence reduction and mortality reduction in a community-based colonoscopy series," Dr. Xirasagar noted.
"Excellent colorectal cancer prevention can be achieved by implementing a protocol that focuses primarily on quality. Colorectal cancer is a preventable disease for 80%-90% of the U.S. population," she maintained.
A session attendee noted that withdrawal time is an important quality indicator in colonoscopy and asked whether she had any data on that measure.
"The total procedure time in the lowest quartile of time was 17 minutes, and the withdrawal time within that was 4.8 minutes," Dr. Xirasagar replied. "Whereas the highest quartile of total time was about 28 minutes."
Giving some background to the study, she noted, "In theory, colonoscopy should prevent 80%-90% of colorectal cancers if we assume that polyps growing over 10-20 years cause colorectal cancer. In reality, as we know, colonoscopy in community-based practice has not lived up to its promise."
Her group set out to prevent all colorectal cancers, with a viewpoint that quality is the most importance endoscopy practice driver, according to Dr. Xirasagar.
They developed a unique colonoscopy protocol that 57 of 59 their group endoscopists use. It entails a personal phone call with prep instructions 2 days before the procedure; administration of propofol sedation by nurse anesthetists; use of two individuals to separately guide the endoscope shaft and head; slow insertion and circumferential withdrawal, with polyp search and removal during both phases; viewing of the video screen and active participation by all of three or four people in the endoscopy room; and referral of patients with large, vascular, or invasive polyps for surgical excision.
Analyses were based on 16,315 patients aged 30-89 years who underwent optimized colonoscopy screening between 2001 and 2008 and had a complete procedure, did not have colorectal cancer at a prior or their first colonoscopy, did not have surgery for a polyp or mass at their first colonoscopy, and did not have polyps measuring 3 cm or more that were sessile or flat.
The patients’ outcomes were ascertained by linking their records to those of a state cancer registry and a vital records registry.
On average, the patients were 58 years old at baseline; 53% were female and 49% were black, according to Dr. Xirasagar, who disclosed no conflicts of interest related to the research. Colonoscopy identified adenomas in 31% of the patients and advanced adenomas in 5%.
After a mean follow-up of 4.8 years, the total number of colorectal cancers expected was 104 based on data for the South Carolina general population, but the total number observed was just 18.
The difference translated to a standardized incidence ratio of 0.17, corresponding to an 83% reduction in incidence with optimized colonoscopy.
Dr. Xirasagar noted that there was considerable background screening going on in the general population during the study period, with 32% of eligible patients undergoing colonoscopy alone. "So one way of thinking is that 104 represents an underestimate of the expected cases in the screening-naive population," she said.
In additional findings, 36 colorectal cancer deaths were expected in the optimized colonoscopy cohort, but only 4 were observed.
This difference translated to a standardized mortality ratio of 0.11, corresponding to an 89% reduction in deaths from this disease with optimized colonoscopy.
The 18 interval colorectal cancers diagnosed in the optimized colonoscopy cohort were roughly equally divided between black and white patients, according to Dr. Xirasagar. Nine were diagnosed at surveillance colonoscopy, half were in the right colon, and three had metastasized at the time of diagnosis.
During the same study period, the observed and expected incidences of lung cancer – used as a control – did not differ significantly in the optimized colonoscopy cohort.
"One of the points this makes is that our study cohort was no more or no less healthy than the general population," she said.