The Veterans Affairs Cooperative Study 380 showed that some advanced colorectal neoplasias in men would be missed with the use of flexible sigmoidoscopy but detected by colonoscopy.
These neoplasias include adenomas at least 1 cm in diameter, villous adenomas, adenomas with high-grade dysplasia, or cancer.
|Sigmoidoscopy alone would have detected 25 women with advanced neoplasia and missed 47|
|New England Journal of Medicine|
In a tandem study, Schoenfeld and colleagues examined the yield of screening colonoscopy in women.
The investigative team determined the prevalence and location of advanced neoplasia and offered colonoscopy to consecutive asymptomatic women referred for colon-cancer screening.
The diagnostic yield of flexible sigmoidoscopy was calculated by estimating the proportion of patients with advanced neoplasia whose lesions would have been identified if they had undergone flexible sigmoidoscopy alone.
The team considered lesions detectable by flexible sigmoidoscopy if they were in the distal colon or if they were in the proximal colon in patients who had concurrent small adenomas in the distal colon, a finding that would have led to colonoscopy.
The researchers compared results with outcomes of the Veterans Affairs Cooperative Study 380 for age-matched men and women with negative fecal occult-blood tests and no family history of colon cancer.
The team completed colonoscopy in 1463 women, 1203 of whom had a family history of colon cancer.
The researchers found that colonoscopy revealed advanced neoplasia in 72 women.
If flexible sigmoidoscopy alone had been performed, advanced neoplasia would have been detected in 25 of these women and missed 47.
The investigators noted that only 35% of women with advanced neoplasia would have had their lesions identified if they had undergone flexible sigmoidoscopy alone, versus 66% of matched men from Veteran Affairs Study 380.
Dr Schoenfeld's team concludes, “Colonoscopy may be the preferred method of screening for colorectal cancer in women.”