Nigerian Postgraduate Medical Journal

: 2021  |  Volume : 28  |  Issue : 1  |  Page : 22--26

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

Yusuf Musa1, Mansur Femi Mohammed2, Nurudeen Olalekan Muhammad3, Ibrahim Yusuf4, Abdulrashid Onimisi Abdulrahim5, Adamu Alhaji Samaila3, Musa Muhammad Borodo3,  
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

Correspondence Address:
Dr. Yusuf Musa
Department of Internal Medicine, Federal Medical Centre, Katsina


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.

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;28:22-26

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 Jun 15 ];28:22-26
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Full Text


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.


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.


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}

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}

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}{Figure 2}{Figure 3}{Figure 4}


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.


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.


1Asombang AW, Madsen R, Simuyandi M, Phiri G, Bechtold M, Ibdah JA, et al. Descriptive analysis of colorectal cancer in Zambia, Southern Africa using the national cancer disease hospital database. PanAfr Med J 2018;30:1-8.
2Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2018;68:394-424.
3American Cancer Society, Inc., Surveillance Research. American Cancer Society. Global Cancer Facts & Figures 4th ed. Atlanta, GA 30303-1002: American Cancer Society; 2018. Available from: [Last accessed on 2020 Jan 01].
4IARC Global Cancer Observatory (Internet). International Agency for Research on Cancer. Latest Global Cancer Data: Cancer Burden Rises to 18.1 Million New Cases and 9.6 Million Cancer Deaths in; 2018. Available from: [Last accessed on 2020 Jan 01].
5Rawla P, Sunkara T, Barsouk A. Epidemiology of colorectal cancer: incidence, mortality, survival, and risk factors. Prz Gastroenterol 2019;14:89-103.
6Gandomani HS, Yousefi SM, Aghajani M, Mohammadian-Hafshejani A, Tarazoj AA, Pouyesh V, et al. Colorectal cancer in the world: Incidence, mortality and risk factors. Biomed Res Ther 2017;4:1656-75.
7Abdulkareem FB, Abudu EK, Awolola NA, Elesha SO, Rotimi O, Akinde OR, et al. Colorectal carcinoma in Lagos and Sagamu, Southwest Nigeria: A histopathological review. World J Gastroenterol 2008;14:6531-5.
8Aminu DM, Iliyasu Y, Yusuf I. Microsatellite instability profile of colorectal cancers in Kano Northwestern Nigeria. Arch Int Surg 2017;7:126.
9Irabor DO, Afuwape OO, Ayandipo O. The present status of the management of colon and rectal cancer in nigeria. J Cancer Res 2014;14:1-7.
10Federal ministry of Health Nigeria (Internet). Nigeria National Cancer Control Plan 2018. Abuja, Nigeria: Federal ministry of Health Nigeria; 2022. Available from: [Last accessed on 2019 Dec 31].
11Sack J, Rothman JM. Colorectal cancer: Natural history and management. Hosp Phys 2000;36:64-73.
12Society of Gastroenterology and Hepatology in Nigeria (SOGHIN) Clinical Practice Guidelines [Internet]. OAUTH Ile-Ife. Management of colorectal cancer in Nigeria in 2016: Society of Gastroenterology and Hepatology in Nigeria. Available from: [Last cited on 2018 Aug 13].
13Ibrahim KO, Anjorin AS, Afolayan AE, Badmos KB. Morphology of colorectal carcinoma among Nigerians: A 30-year review. Niger J Clin Pract 2011;14:432-5.
14Yusuf I, Atanda AT, Umar AB, Imam MI, Mohammed AZ, Ochicha O, et al. Cancer in Kano, Northwestern Nigeria: A 10 Year update of the Kano cancer registry. Ann Trop Pathol 2018;8:87.
15Ebughe GA, Ugbem TI, Ushie DE. Cancer in cross river state. J Adv Med Med Res 2019;30:1-8.
16Kolligs FT. Diagnostics and epidemiology of colorectal cancer. Visc Med 2016;32:158-64.
17Team ACS medical and Editorial Content. American Cancer Society. Colorectal Cancer Causes, Risk Factors, and Prevention. Team ACS medical and Editorial Content; 2018. p. 1-21. Available from: http://www. [Last accessed on 2020 Jan 05].
18Khiari H, Hsairi M. Colorectal cancer incidence and clinicopathological features in Northern Tunisia 2007-2009. Color Cancer 2019;6:131-41.
19Khougali HS, Albashir AA, Daffaalla HN, Salih M. Demographic and clinicopathological patterns of colorectal cancer at the national cancer institute, Sudan. Saudi J Med Med Sci 2019;7:146-50.
20Golfam F, Golfam P, Neghabi Z. Frequency of all types of colorectal tumors in the patients referred to selected hospitals in Tehran. Iran Red Crescent Med J 2013;15:473-6.
21Wong MC, Ding H, Wang J, Chan PS, Huang J. Prevalence and risk factors of colorectal cancer in Asia. Intest Res 2019;17:317-29.
22Mikaeel RR, Price TJ, Smith E, Drew PA, Uylaki W, Horsnel M, et al. Colorectal cancer in Australian young adults. Mathews J Cancer Sci 2019;4:1-18.
23Siegel RL, Miller KD, Fedewa SA, Ahnen DJ, Meester RG, Barzi A, et al. Colorectal cancer statistics, 2017. CA Cancer J Clin 2017;67:177-93.
24Vuik FE, Nieuwenburg SA, Bardou M, Lansdorp-Vogelaar I, Dinis-Ribeiro M, Bento MJ, et al. Increasing incidence of colorectal cancer in young adults in Europe over the last 25 years. Gut 2019;68:1820-6.
25Campos FG, Figueiredo MN, Monteiro M, Nahas SC, Cecconello I. Incidence of colorectal cancer in young patients. Rev Col Bras Cir 2017;44:208-15.
26Irabor D, Adedeji OA. Colorectal cancer in Nigeria: 40 years on. A review. Eur J Cancer Care (Engl) 2009;18:110-5.
27Sierra MS, Forman D. International Agency for Research on Cancer. Etiology of colorectal cancer (C18 – 20) in Central and South America. Lyon: International Agency for Research on Cancer; 2016. Available from: resources. [Last accessed on 2020 Feb 01].
28Irabor DO, Arowolo A, Afolabi AA. Colon and rectal cancer in Ibadan, Nigeria: an update. Colorectal Dis 2010;12:e43-9.
29Saber T, Bedran K, Ghandour F, El Khoury M, Bou Khalil R, Farhat S. Results from a retrospective analysis of colonoscopies for Inflammatory bowel disease and colorectal cancer in a Lebanese tertiary care centre. BMJ Open Gastroenterol 2017;4:e000167.
30Graham A, Adeloye D, Grant L, Theodoratou E, Campbell H. Estimating the incidence of colorectal cancer in Sub-Saharan Africa: A systematic analysis. J Glob Health [Internet]. 2012;2(2). [About 14 p.]. Available from: http:// [Last Citeded on 2019 Dec 23].
31Irabor DO. Ethnic differences in colon and rectal cancer incidence in Nigeria: A case of dietary determinants? Ann Niger Med 2012;6:71-4.