Morphology of colorectal carcinoma among Nigerians: a 30-year review

The incidence of colorectal carcinoma has been on the increase in the developing countries, including Nigeria, as a result of change in diet and adoption of western lifestyle.

The aim of this review is to highlight the prevalence, age and sex distribution, anatomical location, and morphological characteristics of colorectal carcinomas in Ilorin, Nigeria.

This is a retrospective study of all cases of histologically diagnosed colorectal carcinoma in the University of Ilorin Teaching Hospital, Ilorin, Nigeria, over a 30-year period (January 1979-December 2008), using the departmental record and histological slides of the cases.

A total of 241 cases of colorectal carcinoma were reported, 144 cases (60%) in males and 96 cases (40%) in females with a male: female ratio of 1.5:1. The peak age of occurrence for males was between 51 and 60 years, while that of the females was between 41 and 50 years. The malignancy was found in the rectum in 60.2% of the cases, while the least affected site is the descending colon (1.2%). The exophytic occluding masses were found in 82.2% of the cases, and the most common histological type is adenocarcinoma (77.2%) with well-, moderately, and poorly differentiated forms constituting 52.3%, 32.8%, and 14.9% respectively. Of the 241 cases that were seen over the last 30 years, 93 cases (38.6%) were seen in the last 5 years.

Colorectal carcinoma is no longer a rare disease in Nigeria. The surge in the incidence reported in the last 5 years in this center calls for a pragmatic action in its control, with emphasize on colonoscopic screening for those with family history, and possibly making digital rectal examination a mandatory aspect of clinical examination, because most colorectal carcinomas are within the reach of examining finger.