Colonoscopy versus Sigmoidoscopy
Men and women have a lower incidence of colorectal cancer if they also have a history of a negative sigmoidoscopy, negative colonoscopy, or polypectomy for adenoma, according to a new prospective analysis [N Engl J Med. 2013;369:1095-105].
The researchers used data from 2 prospective cohort studies to examine the association between lower endoscopy and colorectal cancer incidence in healthcare professionals over a 22-year period.
The data was derived from the Nurses Health Study and the Health Professionals Follow-Up Study. Participants in the Nurses Health Study (n=121,700) were female nurses who were aged 30 to 55 years at the time of enrollment in 1976, while those in the Health Professionals Follow-Up Study (n=51,529) were male health professionals aged 40 to 75 years at the time of enrollment in 1986. All participants included in this latest study that combined the 2 cohorts (n=88,902) were asked about undergoing sigmoidoscopy or colonoscopy in questionnaires administered every 2 years. The medical records and pathology reports were requested for the participants who said they had received a diagnosis of colorectal polyps.
The primary outcome of the study was mortality from colorectal cancer.
After analyzing the data, researchers found that, overall, participants who had undergone endoscopy had a lower incidence of colorectal cancer. They reported that participants who had undergone endoscopy had multivariate hazard ratios (HRs) of 0.57 (95% confidence interval [CI], 0.45 to 0.72) after having adenomatous polyps removed, 0.60 HRs (95% CI, 0.53 to 0.68) after a having a negative sigmoidoscopy, and 0.44 HRs (95% CI, 0.38 to 0.52) after having a negative colonoscopy when compared with participants who had not had the procedures.
The incidence of distal colorectal cancer was reduced for participants who had a negative colonoscopy (multivariate HR, 0.24; 95% CI, 0.18-0.32), negative sigmoidoscopy (multivariate HR, 0.44; 95% CI, 0.36-0.53), or polypectomy (multivariate HR, 0.40; 95% CI, 0.27-0.59). However, the incidence of proximal colon cancer was only reduced for participants who previously had a negative colonoscopy (multivariate HR, 0.73; 95% CI, 0.57-0.92).
Researchers also reported that endoscopy had an effect on colorectal cancer mortality rates.
