MALIGNANT COLORECTAL TUMOURS IN ZARIA: A TEN-YEAR HISTOPATHOLOGICAL REVIEW (1996-2005)

Abstract

BACKGROUND: Colorectal cancers (CRC) are becoming common worldwide. Colorectal cancer is a lethal disease. Environmental and genetic factors are strong risk factors that influence the development of CRC. Incidence and mortality rates vary from one geographical region to another; high rates are seen in societies with high standard of living. Nigerian patients are found to be younger with twice as many rectal cancers. Majority of patients in Sub-Saharan Africa present with advanced disease and consequently poor prognosis. Incidence of CRC begins to increase between the ages of 40 years to 50 years.

MATERIALS AND METHODS: This retrospective study is based on all records of confirmed cases of colorectal cancers in the Department of Pathology ABUTH. 1996 – 2005. Clinical information was collected from request forms detailed by the physician. All the old slides of the confirmed cases were reviewed by me and the supervisors. Fresh slides were made from archival stores where slides were not available. The reviewed slides were then classified using WHO classification of tumours of Digestive System. The result is presented in form of frequency tables.

RESULTS: A total of 19,668 surgical biopsies were received over the study period in Department of Pathology ABUTH Shika-Zaria of which 3,461 cases are malignant. There were 152 colorectal cancer cases of which 20 were caecal, 7 ascending colon, 3 descending colon, 8 sigmoid colon, and 114 rectal. The commonest histological subtype was adenocarcinoma constituting 106 (69.6%) of all cases followed by colloid carcinoma (17.8%). Colorectal cancer formed 4.4% (152 cases) of all malignancies. Out of the 152 cases 38 (25%) were located in the
colon while 114 (75%) were in the rectum (the ratio of 1: 3). The youngest patient was an 8 year old while the oldest is 80 year old with a mean age of 38.3 years and peak age of 41 to 50 years. There were 94 males and 58 females (ratio of 1.6: 1) for which males were 30 and females 8 (ratio of 1.8: 1) with colon cancers and 64 males vs 50 females (ratio of 1.3: 1) with rectal cancers.

CONCLUSION: Colorectal carcinoma is relatively uncommon in ABUTH Zaria with two third of the tumours occurring in the rectum and have slight male predominance. There is however no trend of occurrence or association with parasitic infestation noted.