Retrospective study of colorectal cancer in Zimbabwe: colonoscopic and clinical correlates

Abstract

Aim: To compare differences in the frequency of colorectal cancer at colonoscopy in Zimbabwe according to ethnicity.

Methods: All lower gastrointestinal endoscopic procedures performed between January 2006 and December 2011 at a gastroenterology clinic in Harare, Zimbabwe were reviewed. The demographic characteristics, clinical indications, differences in bowel preparation and the endoscopic and histological diagnoses were compared between different ethnic groups with emphasis on colorectal cancer. The clinical and demographic characteristics and the endoscopic findings were compared using the student t-test and the χ2 test, while the clinical indications associated with a diagnosis of colorectal cancer were determined by logistic regression.

Results: All colonoscopies and sigmoidoscopies performed in 1236 Caucasians, 460 black Africans and 109 Asians were analysed. Colorectal cancer was diagnosed more frequently in the black African patients compared to Caucasians or Asians (10% vs 3%, 10% vs 2%, P<0.001). However, polyps were less common among black Africans (5%) compared to both Caucasians (8%) and Asians (9%) (P=0.03). Among patients with colorectal cancer, black Africans tended to be younger than Caucasians, who were over-represented in the oldest age category; 32 % vs 2% were less than 50 years and 41% vs 78% were older than 60 years (P<0.001). Anaemia and weight loss were associated with colorectal cancer in both black African [odds ratio (OR): 2.73 (95%CI: 1.33-5.61) and 3.09 (1.35-7.07)] and Caucasian patients [OR: 6.65 (95%CI: 2.93-15.09) and 3.47 (1.52-7.94)].

Conclusion: The likelihood of diagnosing colorectal cancer in patients referred for colonoscopy in Zimbabwe is at least as likely among black Africans as it is among Caucasians.

Keywords: Adenomatous polyps; Africa; Colitis; Colonoscopy; Colorectal cancer; Diverticulosis; Epidemiology.