Prevalence and characteristics of incidental colorectal polyps in patients undergoing colonoscopy at a South African tertiary institution

Abstract

Colorectal cancer (CRC) is the second most common cancer in women, and the third most common in men, and accounts for 10% of all cancers worldwide. [1] Classically, CRCs arise from adenomas, through the adenoma-carcinoma sequence described by Fearon and Vogelstein. [2] The prevalence of adenomas in a population generally correlates with the incidence of CRC. The latter varies widely across the globe, with the USA and Western European countries reporting age-standardised incidence rates per 100 000 population, averaging 29.5 for men and 23.2 for women. [1] This is in sharp contrast to sub-Saharan African countries that report much lower age-standardised incidence rates, ranging from 6.3 in men and 2.7 in women in Mozambique, to the highest rates, i.e. 15.6 in men and 9.5 in women in South Africa (SA). [1,3] Although there are reasonably adequate reports on the epidemiology of CRC in sub-Saharan Africa, data on the prevalence of adenomas are sparse. In an analysis of 91 surgical resections for CRC between 1996 and 1997 in Pretoria, SA (white: n=48; black African: n=43), adenomas were found in 25% of whites and 20% of black Africans. [4] A retrospective review in 1999 reported that of 172 CRC resections in black Africans on the Witwatersrand, SA, 5% This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.

Hyperplastic polyp or sessile serrated lesion? The contribution of serial sections to reclassification

“…In contrast, a review of colonoscopy records conducted in Cape Town, South Africa showed that of 246 polyps, 10.6% were hyperplastic and only 1.6% were serrated adenomas. The latter were not further subclassified [ 49 ]. In an Egyptian study, HPs accounted for 15% of non-adenomatous polyps, the majority being hamartomatous.…”

Colonoscopy practice in South Africa: The way forward

“…In contrast, the second study, from an academic state institution, Groote Schuur Hospital, Cape Town, reviewed 992 colonoscopies in people at average risk of colorectal cancer. [7] The ADR in this study was 12% (18% in white and Asian patients (16/103 and 2/13, respectively), 13% (95/757) in the mixed-race population and 5% (6/119) in black South Africans). Although these studies are hospital based, and not truly reflective of the typical healthy adult population for which ADR is regarded as the benchmark, they provide a solid basis for clinical practice in SA and the rest of Africa.…”

“…In this issue of SAMJ, two studies for the first time report information assessing the quality of colonoscopy in the public and private sectors. [6,7] It is heartening that the CIR in both studies meets international targets. However, the proportion of examinations with adequate bowel preparation falls short of recommendations.…”

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“…Generally, the adenoma detection rates among patients seeking colonoscopy are lower across the African continent. [9][10][11] It is more likely to diagnose CRC in black patients presenting for colonoscopy, despite the paradoxical low polyp detection rates. This is because the black African population are more likely to present for colonoscopy after onset of alarm symptoms.…”