Epidemiology and anatomic distribution of colorectal cancer in South Africa.

Background: Colorectal cancer (CRC) is the fifth most common cancer in sub-Saharan Africa (SSA) and the third most common in South Africa (SA). CRC characteristics in SSA are not well described. The aim is to describe patient characteristics and anatomic location of colorectal adenocarcinoma (CRC-AC) in SA.

Methods: A retrospective analysis of the histology specimens of CRC in SA through utilisation of the South African National Cancer Registry from 2006 to 2011.

Results: Six thousand one hundred and forty-six patients with colorectal malignancies were identified of which 5 498 (89%) had CRC-AC. The median age at presentation was 60 (interquartile range, 49-70) years. One thousand three hundred and seventy-two (25%) were < 50 years and 2 870 (52%) were male. Right colonic tumours were found in 1 277 (26%), 1 214 (25%) were left colonic lesions, and 2 404 (49%) lesions were located in the rectum. Patients ≥ 50 years at presentation (OR = 1.29, 95% CI = 1.11-1.50, p < 0.001) were more likely to have left colonic and rectal adenocarcinoma. Patients < 50 years at presentation were more likely to be black (OR = 1.67, 95% CI = 1.39-2.02, p < 0.001) and have right-sided tumours (OR = 1.25, 95% CI = 1.06-1.46, p < 0.007).

Conclusion: CRC-AC in SA presents at an earlier age than in HICs, such as the United States of America. The majority of CRC were left-sided and rectal; thus, screening with faecal immunochemical testing and flexible sigmoidoscopy should be considered. Further studies on the age-specific incidence and the genetics and epigenetics and socioeconomic determinants of CRC-AC in SA are needed.