CLINICOPATHOLOGICAL STUDY OF COLORECTAL CARCINOMAS WITH SPECIAL REFERENCE TO TNM STAGING 2 SYSTEM AT LAGOS UNIVERSITY TEACHING HOSPITAL (A TEN YEAR RETROSPECTIVE STUDY FROM 1997 TO 2006)

Abstract

At the Lagos University Teaching Hospital, Lagos, Nigeria, over a 10-year period (January 1997
to December 2006), we found 170 cases of histologically confirmed colorectal carcinoma in a total
number of 23,498 surgical biopsies giving a yearly biopsy occurrence of 17. Two hundreds and forty –
six (246) cases of gastrointestinal tract cancers which constituted 12.57 % of a total number of
malignancies (1954 cases) were diagnosed during 10 years period. Colorectal carcinomas accounted
for 8.7% of all malignancies as well as 68.8% of total gastrointestinal tract cancers.
The age range was from 15 years to 81 years. In both sexes, the mean age was 50.8 years while
the peak age of occurrence was between 51 and 60 years. Seventy-eight (58.2%) cases occurred in
males while 56 (41.8%) occurred in females, with a male to female ratio of 1.4:1.
Rectum or rectosigmoid was the site of predilection (70 patients, (52.0%) or 86 patients, (64.2%)
respectively) for colorectal carcinomas with the colon to rectum ratio of 1:1.09. Left sided carcinomas
predominated in 93 (69.4%) cases and the remaining cases, 41 (30.6%) were right sided carcinomas
giving a ratio of 2.3: 1.
The commonest gross appearance in this series was the exophytic / polypoidal / fungating lesions
(49.3%), followed by annular - constricting (43.3%) and diffusely infiltrating/ulcerative lesions (7.4%).
Three cases (2.23%) of adenomatous polyps co-existing with colorectal carcinoma were also described.
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The predominant histological type was adenocarcinoma (79.9%) showing varying degrees of
differentiation with the well differentiated type predominating, 62 (46.3%) cases. Mucinous
adenocarcinoma constituted 17.2%, anaplastic carcinoma, 2.2%, and signet ring carcinoma, 0.7%.
Thirty-one (23.1%) patients with colorectal carcinoma were aged 40 years and below with a
mean age of 33.09 years and male to female ratio of 1.8:1. In this younger population, left sided
carcinomas predominated while adenocarcinoma was the commonest histologic type. Mucinous
carcinomas were mostly left, sided and with a male to female ratio of 1:1.1. The only case of signet
ring carcinoma was left sided while one case of anaplastic carcinoma was seen in this study.
Colorectal carcinoma was advanced in 26 (26.5%) cases which consisted of T2N1M0 (Stage
IIIA) in 6.12%, T3N1M0 (Stage IIIB) in 19.39%, and T4N0M1 (Stage IV) in 1.02% cases. Also, the
advanced stage of colorectal carcinoma has slight male preponderance with a male to female ratio of
1.2 : 1 and these were seen commonly in the patients 40 years and above in 19, (19.4%) cases.