Prevalence of advanced histology in diminutive colonic polyps in an average risk population: implications for colorectal cancer screening

Notizia del 04/04/2009

Scritto da admin

Authors (first name, last name):

• Andrea Buda [1]
• Eva Zabeo [1]
• Manuela De Bona [3]
• Renzo Barbazza [2]
• Pierluca Piselli [5]
• Angelo Bellumat [3]
• Flavio Valiante [3]
• Massimo Pignatelli [4]
• Giacomo C. Sturniolo [1]
• Michele De Boni [3]

Abstract body - Introduction:

A primary goal of colorectal cancer prevention is the identification and removal of premalignant colonic polyps. Clinical management of diminutive polyps (1-5 mm) is an area of controversy since their natural history is poorly defined. Few data are available on the prevalence of advanced histology in diminutive polyps in an average risk patients' population.

Aims & methods:

Aim of this study was to determine the prevalence of advanced histologic features in polyps removed during white light conventional colonoscopy. Methods. A consecutive series of patients undergoing colonoscopy over 18-month period was studied. 915 average risk subjects (group A), 1760 patients with lower gastrointestinal symptoms (group B, rectal bleeding, anemia, change in bowel habits, weight loss)and 446 asymptomatic patients with positive FOBT + (group S) at first colonoscopy were included. Only patients without history of CRC or adenomas, inflammatory bowel disease were enrolled. Advanced histology was defined as high grade dysplasia, villous histology and carcinoma.

All colonoscopies were performed with white light conventional endoscopes, the mean withdrawal time 10.3 min and the ciecum was reached in 96% of cases. For purposes of the analysis, the junction of the splenic flexure and the descending colon, as determined by the endoscopist, defined the border between the proximal and the distal colon. All retrieved polyps (flat, sessile and peduncolated) were examined by 2 independent pathologists.

Results:

Among 3121 patients included (44.8% M, median age 60 years), 861 (27.6%) had polyps with complete histology in 827 (96%). Most were adenomas (72.3%), followed by serrated adenomas (SA, 18.7%) and hyperplastic polyps (9%). Diminutive (1-5 mm) polyps account for the 73.6% of all lesions detected. Overall advanced histology was found in 30.2% polyps. Advanced histology was found in 19.3% of 1-5 mm polyps, 37.7% of 6-10 mm and 61.5% of > 10 mm polyps. Considering different subgroups of patients, the proportion with advanced histology in 1-5 mm polyps was 8.9% in A, 15.9% in B and 20.5% in S. There were no carcinomas in polyps less than 5 mm in size.

Conclusion:

The prevalence of advanced histology in 1-5 mm polyps detected in average risk patients is higher than previous reports. Diminutive polyps harbor pathologically significant histology as high grade dysplasia or villous elements and the need of their removal should be re-addressed in order to optimize colorectal cancer prevention.

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