Flexible sigmoidoscopy screening lowers incidence of colorectal cancer and death rate

by Bruce Sylvester – Compared to no screening, flexible sigmoidoscopy screening has resulted in a reduced incidence of colorectal cancer and rate of death from colorectal cancer, researchers in the August 13, 2014 issue of JAMA/Journal of the American Medical Association.

Øyvind Holme, M.D., of the Sorlandet Hospital Kristiansand, Kristiansand, Norway and his team randomized subjectsto receive once-only flexible sigmoidoscopy (n=10, 283), a combination of once-only flexible sigmoidoscopy and fecal occult blood testing (FOBT; n=10,289), or no intervention (control group; n=78,220).

They screened and enrolled the subjects in 1999-2000 (55-64-year age group) and in 2001 (50-54-year age group). They followed each subject until December 2011.

After a median of 11 years, they found that colorectal cancer had been diagnosed in 253 subjects in the screening groups and 1,086 in the control group. And 71 subjects in the screening groups had died of colorectal cancer compared to 330 in the control group.

When compared to no screening, flexible sigmoidoscopy screening reduced colorectal cancer incidence by 20 percent (absolute difference, 28.4 cases/100,000 person years) and colorectal cancer mortality by 27 percent (absolute difference, 11.7 deaths/100,000 person years).

The investigators found no significant difference in outcomes between the flexible sigmoidoscopy only ground and the flexible sigmoidoscopy plus FOBT screening group.

Younger subjects (50 to 54 years old) appeared seemed to benefit as much from the screening interventions as older participants ages 55 to 64 years.

Noting advances in research on stool test screening, Allan S. Brett, M.D., of the University of South Carolina School of Medicine, Columbia, S.C., wrote in an editorial accompanying the study, “A large, recently published study examined the performance of a multi-target stool test that identifies several DNA abnormalities associated with colorectal cancer or precancerous adenomas. With colonoscopy as the reference standard, the sensitivity of the stool DNA test was 92 percent for detecting cancer and 42 percent for detecting advanced precancerous lesions; specificity was 90 percent. Notably, the stool DNA test was much more sensitive than a separate fecal immunochemical test for hemoglobin performed for each participant. Repeated at some defined interval, stool DNA testing has potential to reduce colorectal cancer mortality substantially while sharply reducing the number of routine colonoscopies. For now, however, the muddled landscape of colorectal cancer screening in the United States continues, and the place of flexible sigmoidoscopy among screening tools remains unsettled.”