Five-year risk of colorectal neoplasia after negative screening colonoscopy.
BACKGROUND
The appropriate interval for endoscopic rescreening after a negative colonoscopic examination is uncertain.


METHODS
We identified persons with no adenomas on baseline screening colonoscopy who returned at 5 years for follow-up colonoscopy. Findings were categorized according to the most advanced lesion present: no polyp, a hyperplastic polyp, a tubular adenoma less than 1 cm in diameter, an advanced adenoma (a tubular adenoma > or = 1 cm in diameter or a polyp with villous histologic features or high-grade dysplasia), or a cancer.


RESULTS
Baseline screening colonoscopy had identified 2436 persons with no adenomas; 1256 of them (51.6%) were rescreened a mean (+/-SD) of 5.34+/-1.34 years later. The mean age of this group at baseline was 56.7 years; 56.7% of its members were men. No cancers were found on rescreening (95% confidence interval [CI] for the detection rate, 0 to 0.24%). One or more adenomas were found in 201 persons (16.0%). A total of 19 advanced adenomas, of which 10 (52.6%) were distal to the splenic flexure, were found in 16 persons (1.3%). The risk of an advanced adenoma did not differ significantly between persons with no polyps at baseline and those with hyperplastic polyps at baseline (1.1% [12 of 1057] and 2.0% [4 of 199], respectively; P=0.30). Men were more likely than women to have any adenoma (tubular less than 1 cm in diameter or advanced) (relative risk, 1.88; 95% CI, 1.42 to 2.51) and to have an advanced adenoma (relative risk, 3.31; 95% CI, 1.02 to 10.8).


CONCLUSIONS
Among persons with no colorectal neoplasia on initial screening colonoscopy, the 5-year risk of colorectal cancer is extremely low. The risk of advanced adenoma is also low, although it is higher among men than among women. Our findings support a rescreening interval of 5 years or longer after a normal colonoscopic examination.
Imperiale
Thomas F
TF
Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, USA.
Glowinski
Elizabeth A
EA
Lin-Cooper
Ching
C
Larkin
Gregory N
GN
Rogge
James D
JD
Ransohoff
David F
DF
D000230:Adenocarcinoma / Q000175:diagnosis / Q000453:epidemiology*; D000236:Adenoma / Q000175:diagnosis / Q000453:epidemiology*; D003111:Colonic Polyps / Q000175:diagnosis / Q000453:epidemiology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk; D012680:Sensitivity and Specificity; D013997:Time Factors