San Diego—Using standard colonoscopic equipment and adhering to a strict but reasonable protocol, a gastroenterology group in South Carolina was able to achieve the greatest reduction in colorectal cancer (CRC) incidence and CRC-related mortality ever documented in a community-based colonoscopy series.

“The group believes that any CRC case is one too many, and that quality is the single most important endoscopy [variable],” Sudha Xirasagar, MBBS, PhD, associate professor of Health Services Policy and Management at the University of South Carolina, Columbia, said during the 2013 Annual Scientific Meeting of the American College of Gastroenterology (ACG).

With a goal of 100% CRC prevention, the South Carolina Medical Endoscopy Center practices the following measures:

  • Patients are contacted with bowel preparation instructions two days before the procedure.
  • Patients undergo propofol sedation administered by nurse anesthetists.
  • The procedure is done using a two-person endoscopy technique, with a technician pushing the endoscope and providing torque, and the endoscopist managing the polyp search-and-removal process.
  • Adequate time is allowed for thorough examination of the colonic mucosa during both insertion and withdrawal, with polyps removed in all cases.
  • All personnel in the room view the video monitor and actively participate in the examination.
  • Large invasive or vascular polyps are referred to a surgeon for excision.

To examine the effect of this protocol, the group commissioned an independent evaluation of their colonoscopy outcomes, in which academic researchers compared colonoscopy cohort data from October 2001 to December 2008 with data from the South Carolina Central Cancer Registry from 1996 to 2009. Investigators looked for cases of CRC, in addition to two control cancers, lung and brain; they also conducted a data merge with the state’s Vital Statistics Registry to identify deaths.

Patients were excluded from the analysis if they had missing Social Security numbers, were younger than age 30 or older than age 90, had CRC before or discovered during the initial screening, had a prior or scheduled surgical resection of a colonic mass or lesion, had a polyp 3 cm or larger at the initial colonoscopy, or had an incomplete colonoscopy without a repeat procedure within three months.

The final cohort consisted of 16,351 patients who were compared with the state’s general population and Surveillance Epidemiology, and End Results–18 population for CRC incidence and CRC-related mortality. The investigators found an adenoma detection rate of 31.4%, with an adenoma detection rate for advanced adenomas of 5.2% and an average follow-up of 4.8 years. Patients with adenomas were asked to return for surveillance according to the guidelines of the ACG/American Society for Gastrointestinal Endoscopy.

Based on data from the state’s general population, researchers expected to find 104 new cases of CRC; however, the observed number was only 18.

“This resulted in a standardized incidence ratio of 0.17 and a CRC incidence reduction of 83%,” Dr. Xirasagar noted.

“To put this into perspective, the 18 cases in the study cohort are being compared with the [general population of] South Carolina, which has significant background screening going on, about 32% over the study period for colonoscopy itself. So, the 104 expected cases would represent an underestimate of the expected cases in a screening-naive population.”

The difference between expected and actual CRC-related mortality was equally impressive.

“Thirty-six CRC deaths were expected, but there were only four observed deaths, for a standardized mortality ratio of 0.11 and a mortality reduction of 89%,” Dr. Xirasagar said.

Of the 18 interval cancers that occurred, half were diagnosed at the follow-up surveillance colonoscopy, slightly less than half occurred in the left colon and three were diagnosed with distant metastases.

Also worth noting, the researchers expected to find 149 lung cancers in the study cohort and observed 143, a reduction of virtually zero, illustrating “that our study cohort was no more or less healthy than the general population,” Dr. Xirasagar said.

Also notable was the fact that even the patients who were excluded from study because of existing or probable cancer at the initial colonoscopy tended to fare much better compared with the general population.

“The vast majority of the CRC cases in this study population were those who had cancer at the initial colonoscopy,” Dr. Xirasagar said. “Combining those cases with those who developed [CRC] among other excluded patients, 95 patients were alive and well by the end of the study period, and 24 had died, which is an extremely good ratio of mortality to incidence compared with the natural history in the general population.”

With a CRC incidence reduction of 83% and a CRC-related mortality reduction of 89%, the researchers concluded that “excellent CRC prevention can be achieved by implementing a protocol that focuses primarily on quality and that CRC is a preventable disease for 80% to 90% of the U.S. population.”

The Importance of Being Careful

Rami Abbass, MD, a partner with University Gastroenterology Associates, University Hospitals, in Cleveland, who was not involved in the study, agreed with the South Carolina group’s focus on quality.

For example, his group has found that calling patients two days ahead of their procedure rather than just one day before had a substantial effect on the quality of bowel preparation.

“It gives patients time to make some small adjustments with their diet or with taking their prep,” Dr. Abbass said. “With one day’s notice, sometimes they can’t make some of those adjustments.”

Dr. Abbass’ group also uses propofol sedation, which he thinks allows endoscopists to have a better focus on the procedure, as patients are less apt to move about. His team also keeps meticulous notes on withdrawal times as part of their involvement with the ACG’s GI Quality Improvement Consortium program. He feels that these efforts help create an atmosphere among nurses, technicians and physicians, where quality is of the highest importance.

Dr. Abbass and his colleagues also agree with the South Carolina group’s protocol of inspecting the mucosa on insertion and withdrawal.

“Careful inspection on withdrawal is more commonly taught in training programs, but if you’re doing it on insertion too, you are giving yourself more time and may be able to see more,” Dr. Abbass said, noting that occasionally small adenomas seen on insertion are hard to relocate and remove on withdrawal. “What’s important is to spend an adequate amount of time inspecting the mucosa.”

Dr. Abbass and his group encourage nurses to watch the video screen during procedures, too, and the nurses occasionally see subtle lesions that gastroenterologists have missed. He also finds that gastroenterologists can detect subtle lesions by retroflexing in the ascending colon.

Where Dr. Abbass questions the South Carolina group’s protocol, however, is in the use of a two-person technique during endoscope insertion.

“I like to have full control of maneuvering the endoscope. If I’m able to torque the scope myself, I get better visualization because I get a feel for every turn. If someone else was torquing for me, they’d have to be reading my mind,” he said.

“I think the big highlight here is that there are things we can track that will improve outcomes,” Dr. Abbass said. “I’m not surprised that the more careful we are, the better we view the colon and the better the long-term outcomes are in preventing interval cancers.”

Drs. Xirasagar and Abbass reported no relevant conflicts of interest.