Histological assessment of colorectal adenomas by size. Are polyps less than 10 mm in size clinically important?
OBJECTIVE
To define the relative risk of malignant transformation in colorectal adenomas less than 10 mm in diameter.


METHODS
Prospective study.


METHODS
District general hospital, UK.


METHODS
1228 polyps detected endoscopically in 445 patients over the 10-year period 1989-1999.


METHODS
Site, size, histological type and dysplastic grade of polyp.


RESULTS
657 of the 1228 polyps were adenomas: 281 (43%) tubular, 339 (51%) tubulovillous and 37 (6%) villous. In the 357 adenomas less than 10 mm in diameter, 11 (3%) were severely dysplastic and 2 carcinomas were detected, though neither was less than 5 mm in size. The relative risk of malignancy or severe dysplasia in adenomas of 10 mm or more compared with those of less than 10 mm was 3.8 (p < 0.0001).


CONCLUSIONS
Although severe dysplasia and malignancy do occur in adenomas less than 10 mm in size, they are rare in lesions of less than 5 mm. We recommend routine destruction of all polyps 5 mm or more in size, though it is not essential to remove those of less than 5 mm if they are kept under surveillance.
Aldridge
A J
AJ
Department of Surgery, St Richard's Hospital, Chichester, UK.
Simson
J N
JN
D000236:Adenoma / Q000473:pathology*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D003111:Colonic Polyps / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution