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 Table of Contents  
Year : 2021  |  Volume : 28  |  Issue : 1  |  Page : 22-26

Clinical, endoscopic and histological profile of colorectal cancers seen on colonoscopy in Kano, North-Western Nigeria

1 Department of Internal Medicine, Federal Medical Centre, Katsina, Katsina State, Nigeria
2 Department of Internal Medicine, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria
3 Department of Internal Medicine, Aminu Kano Teaching Hospital and Bayero University Kano, Kano State, Nigeria
4 Department of Histopathology Aminu Kano Teaching Hospital and Bayero University, Kano, Nigeria
5 Department of Internal Medicine, Federal Medical Centre, Azare, Bauchi State, Nigeria

Date of Submission02-Sep-2020
Date of Decision01-Oct-2020
Date of Acceptance28-Nov-2020
Date of Web Publication25-Feb-2021

Correspondence Address:
Dr. Yusuf Musa
Department of Internal Medicine, Federal Medical Centre, Katsina
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/npmj.npmj_288_20

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Background: Colorectal cancer (CRC) is the most prevalent gastrointestinal (GI) cancer. With 5% risk of developing CRC in life, it became the third leading cause of cancer death in developed nations. In Nigeria, it is the most common GI cancer. However, there are limited data on CRC in the study area (North-Western part of Nigeria). The aim of this study was to identify the clinical, endoscopic and histological profile of CRC seen on colonoscopy. Methodology: This was a retrospective descriptive study where colonoscopic and histological records of suspected CRC in the study centre between January 2008 to December 2017 were evaluated. Results: Records of 135 patients were reviewed, and males constituted 63.7%. The mean age was 46.61 ± 16.80 years, with 30–39 years as a modal group. Common presentations were diarrhoea (86.7%) and bleeding per rectum (68.9%). Areas affected were rectosigmoid colon (63%), ascending colon (14.1%), descending colon (8.9%), transverse colon (7.4%) and anal canal (6.7%). Histologically, adenocarcinoma was reported in 57.8%, mucinous adenocarcinoma in 8.1% and signet ring cell adenocarcinoma in 3.7%. Tubular and villous adenomas were 3% each. Others were carcinoid tumours (1.5%), metastatic adenocarcinoma, squamous cell carcinoma, basal cell carcinoma, GI stromal tumour, inflammatory myofibroblastic tumour, angiosarcoma and adenoid cyst carcinoma reported in 0.7% each. Conclusion: Majority of the patients with CRC were in their young age. The most common presentations were diarrhoea, weight loss and anaemia. The most common site of affectation was in the left colon, while the most common histological finding was adenocarcinoma.

Keywords: Adenocarcinoma, anal canal, ascending colon, colonoscopy, colorectal cancer, descending colon, mucinous adenocarcinoma, rectosigmoid colon, signet ring adenocarcinoma, transverse colon, tubular adenoma, villous adenoma

How to cite this article:
Musa Y, Mohammed MF, Muhammad NO, Yusuf I, Abdulrahim AO, Samaila AA, Borodo MM. Clinical, endoscopic and histological profile of colorectal cancers seen on colonoscopy in Kano, North-Western Nigeria. Niger Postgrad Med J 2021;28:22-6

How to cite this URL:
Musa Y, Mohammed MF, Muhammad NO, Yusuf I, Abdulrahim AO, Samaila AA, Borodo MM. Clinical, endoscopic and histological profile of colorectal cancers seen on colonoscopy in Kano, North-Western Nigeria. Niger Postgrad Med J [serial online] 2021 [cited 2021 Jul 30];28:22-6. Available from: https://www.npmj.org/text.asp?2021/28/1/22/310158

  Introduction Top

Colonic and rectal malignancies are very common cancers globally.[1] Colorectal cancer (CRC) is the third most common cancer in both sexes and the second most common cause of cancer-related deaths.[2],[3],[4],[5] Incidence and prevalence are on the rise globally, but early detection and modern treatment facilities in industrialised nations have made its morbidity and mortality to be more glaring in unindustrialised nations.[5],[6],[7],[8] This in part is related to the establishment of screening programmes, with early cancer detection in such nations, unlike what is obtainable in developing countries like Nigeria.[9],[10]

CRC is the fourth most common malignancy amongst men and women in Nigeria.[10] The actual Nigerian incidence and prevalence of CRC are lacking. However, the estimated prevalence is about 3.4 cases per 100,000 population,[11] while the incidence is 6.4–8.7 and ≤6.3 per 100,000 in males and females, respectively.[2],[3] Similarly, the combined incidence for both sexes was 5.5–6.5/100,000.[5] CRC is recently found to be the most common gastrointestinal (GI) tumour in Nigeria.[7],[12],[13],[14],[15]

Cancer of the colon was found to have an incidence of 3.3 and 3.0 for males and females in West Africa in 2018, while rectal cancer had 2.7 and 2.1 for the two sexes.[2],[3] CRC has a global incidence of 19.7 for both sexes with 23.6 and 16.3 for males and females, respectively.[2],[3],[5]

CRC, though previously reported mainly amongst the middle aged and elderly worldwide,[1],[6],[7],[9],[11],[13],[16],[17],[18],[19],[20],[21] is now increasingly reported amongst younger individuals even before the age of 20.[22],[23],[24],[25] Similarly, CRC has been postulated to be seen one or two decades earlier in Africans compared to Caucasians.[26]

CRC has a variety of modifiable and non-modifiable risk factors. The non-modifiable factors are ethnicity, hereditary cancer syndromes, family history of CRC, male gender, advancing age, long stature, history of adenomatous polyps, history of inflammatory bowel disease, type 2 diabetes mellitus, previous CRC, cystic fibrosis, abdominal radiation during childhood and cholecystectomy amongst others.[5],[6],[11],[12],[16],[17],[21],[22],[27] On the other hand, modifiable risk factors include obesity, physical inactivity, consumption of excessive red meat, fat and processed food, excessive calcium intake excessive alcohol intake, low fibre intake, low Vitamin D, reduced fruits and vegetable intake, cigarette smoking, low socio-economic status and some gut microbiota. However, high fibre diet, fruits, vegetables and non-steroidal anti-inflammatory agents are said to be protective.[5],[6],[11],[12],[16],[17],[21],[22],[27]

Early-onset CRC is asymptomatic in >80% of cases, but non-specific symptoms such as malaise, weight loss, lassitude, abdominal pain, change in bowel habits and haematochezia are less common. Similarly, late-onset CRC (LOCRC) may be asymptomatic or identified during routine screening exercise on colonoscopy. However, advanced LOCRC (Stage III or IV) may present with distant metastasis and/or complications,[22],[25] features of obstruction, perforation, bleeding, abdominal pain, asthenia, anaemia, altered bowel habit feeling of mass per abdominal, bowel perforation and other constitutional features.[11],[12],[22],[26]

CRC prevention involves screening and lifestyle and dietary changes, exercise, weight reduction and removal of polyps during screening. Drugs such as aspirin, bisphosphonates, statins and hormones have been shown to have some protective effect.

Screening methods include faecal occult blood testing, faecal immune-histochemical test and faecal DNA, flexible sigmoidoscopy, computed tomography colonography, double-contrast barium enema and colonoscopy.[5],[12],[16]

The aim of this study is to evaluate retrospectively the clinical profile of patients found with colonic tumour on endoscopy, various sites of affectation and histology of such lesions.

  Methodology Top

This is a retrospective descriptive study of CRCs diagnosed over 10 years during endoscopy from January 2008 to December 2017 in the Endoscopy Unit and Histopathology Department, Aminu Kano Teaching Hospital, Kano, Nigeria.

Aminu Kano Teaching Hospital is an institution in Kano city, North-Western Nigeria. It is equipped with an endoscopy suite since 1992 and manned by gastroenterologists from the Department of Internal Medicine. The unit receives requests from Jigawa, Katsina, Bauchi, Yobe, Borno and Zamfara states. The unit has also a colonoscopy suite which is equipped with an Olympus adjustable procedure couch, Pentax EPK-1000 video colonoscope, Olympus Optera CV-170 video system with ADVAN AMM215WTD Monitor, TE-NE Compact Trolley assembly and CF-H170 colonoscope. The common agents used for bowel preparation are oral and rectal Bisacodyl (Dulcolax) as well as castor oil and 20% diluted oral mannitol. Boston Bowel Preparation Score is the most common guide used for assessing the adequacy of bowel preparation.

The endoscopy register was reviewed, and all the patients with suspected CRC between January 2008 and December 2017 were isolated and their relevant data such as sex, age and symptomatology or indication for the procedure as well as endoscopic findings were noted accordingly. The biopsies taken were followed up at the Histopathology Department of the same institution where previous histology registers were checked for confirmation of histological diagnosis.

Variables were recorded on Microsoft Excel sheet version 2016 and transferred into computer-based Statistical Program for the Social Sciences (SPSS) software version 20.0 (SPSS Inc., Chicago IL, USA) for analysis. Qualitative variables were summarised using mean and standard deviations and their differences determined using the t-test. Quantitative variables were grouped into proportions, median, interquartile range and percentages and their associations determined using the X2 test. A confidence interval of 95% was used, and P < 0.05 was considered statistically significant.

  Results Top

After thorough evaluation of the register, 135 patients fulfilled the colonoscopic finding of CRC with male preponderance (63.7%). The mean age of the participants was 46.61 ± 16.03 years, with a range of 15–80 years. The modal age was 30 years while the modal age group is 30–39 years. Overall young and middle-aged participants seem to have equal frequency of occurrence amongst the study participants. Similarly, the most common presenting symptom was loose stool, followed by weight loss, anaemia and rectal bleeding. The detail distribution of age and clinical presentations is shown in [Table 1].
Table 1: Age distribution and clinical presentations of patients on colonoscopy

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Rectosigmoid colon was the most common area of affectation, followed by ascending colon. Conversely, anal canal was the least affected. Anal canal, rectosigmoid and right colon affectations were commonly seen amongst the young, middle aged and elderly, respectively. Similarly, colonic polyps were found to be more associated with rectosigmoid tumours.

The most common CRC seen on histology was adenocarcinoma, followed by mucinous adenocarcinoma. Mucinous, signet ring adenocarcinoma and villous adenoma were more common amongst the young (45.5%, 80% and 75%, respectively), while adenocarcinoma was more common in the middle aged (46.2%). [Table 2] shows the various tumour sites and histological subtypes identified.
Table 2: Colonoscopic and histological characteristics of suspected colorectal cancer

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Other histological lesions identified were metastatic adenocarcinoma, squamous cell carcinoma, basal cell carcinoma, GI stromal tumour, inflammatory myofibroblastic tumour, angiosarcoma and adenoid cyst carcinoma.

[Figure 1], [Figure 2], [Figure 3], [Figure 4] show the original pictures of the colonoscopic and histologic findings of some of the patients.
Figure 1: Suspected tumour seen at rectosigmoid colon on endoscopy

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Figure 2: Photomicrography of adenocarcinoma

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Figure 3: Photomicrography of mucinous adenocarcinoma

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Figure 4: Photomicrography of signet ring adenocarcinoma

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  Discussion Top

In this 10-year review, CRC was more prevalent amongst males with a M: F ratio of 1.75:1, a finding similar to many previous studies.[7],[20],[28],[29],[30] Presence of CRC was found to be commoner among younger individuals in our study, a finding somehow different from commonly reported figures.[7],[14],[19],[20],[31]However, these figures are in keeping with recently reported ones.[1],[28] This is important to note in our day-to-day practice where we commonly consider CRC in elderly individuals and also consider the possibility of lowering the age limit for screening colonoscopy in our setting.

All the patients present with a myriad of symptoms ranging from diarrhoea to melena stool, with diarrhoea as the most common. This shows how most of our patients present with advanced disease as obtained in most developing nations from previous studies.[1],[19] This calls for more enlightenment amongst the public and health workers, especially doctors to have a high index of suspicion in any patient presenting with some of the common features of CRC such as diarrhoea, weight loss and anaemia regardless of their age at presentation.

Rectosigmoid colon is the most common site of affection amongst the participants consisting of almost two-third of the study findings, while anal tumour was the least frequent. This is similar to most of the reported cases in both developing and developed nations.[1],[7],[13],[18],[19],[20],[28],[30],[31]

Adenocarcinoma constitutes the most predominant histological type of CRC identified on pathological analysis, followed by mucinous adenocarcinoma and signet ring adenocarcinoma. However, about 5% of the participants have no traceable histology reports, and this may likely be due to the patients taking their tissues outside the hospital for analysis. The above histological findings go in tandem with various studies reported previously where adenocarcinoma constitutes a modal histology pattern.[1],[7],[13],[18],[28] Mucinous adenocarcinoma and signet ring adenocarcinoma were more common amongst the young participants as reported in some studies from Nigeria and beyond.[7],[8],[14],[19],[31] The two histological subtypes are known to have poorer outcomes. This is a serious cause for concern, especially considering the category participants involved.

  Conclusion Top

It is obvious that CRC mainly present late in North-Western Nigeria in advanced stage with overwhelming symptomatology. Hence, the prognosis is usually guarded. It is, therefore, imperative for the stakeholders concern to employ possible means of detecting these tumours earlier through screening programmes that could detect pre-cancerous lesions. The modal age group affected by this potentially preventable disease was in their young age, and more importantly, they were affected by histological type with worst outcome, hence the youths may need to be considered for CRC screening programmes.


Drs. Yussuf A Maisuna, Mohammed A Nahuche, Yusuf S Umar, Muhammad Manko and other supporting staffs at the Endoscopy and Histopathology Department.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2]


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