Colorectal carcinoma: why is there a lower incidence in Nigerians when compared to Caucasians?

Dietary risk factors for colorectal cancer in Uganda: a case-control study

INTRODUCTION

Low-income countries in East Africa have a lower incidence of colorectal cancer (CRC) than high-income countries; however, the incidence has steadily increased in the last few decades. In Uganda, the extent to which genetic and environmental factors, particularly dietary factors, contribute to the aetiology of CRC is unclear. Therefore, the objective of our study was to determine the relationship between dietary factors and CRC in Uganda.

METHODS

We conducted a case-control study and recruited 128 cases and 256 controls, matched for age (± 5 years) and sex. Data regarding the frequency of consumption of the dietary factors were obtained from all the participants using an interview-based questionnaire. The potential dietary risk factors and protective factors evaluated included the type and frequency of meat consumed and the type and frequency of high-fibre foods consumed. The frequency was either 4 or more times/week, 2-3 times/week, once/week or never. Conditional logistic regression analyses were used to determine the odds ratios associated with the different risk and protective factors.

RESULTS

The median age (IQR) for the case participants was 55.5 (43-67.5) years, and that of the control participants was 54 (42-65) years. The male-to-female ratio was 1:1 for all the participants. Factors significantly associated with CRC cases included:- the consumption of boiled beef 2-3 times/week (aOR:3.24; 95% CI: 1.08-9.69; p < 0.035). Consumption of high-fibre foods, including:- millet for ≥ 4 times/week (aOR: 0.23; 95% CI: 0.09-0.62; p = 0.003)), spinach for ≥ 4 times/week (aOR:0.32; 95% CI: 0.11-0.97; p = 0.043), and potatoes 2-3 times/week (aOR: 0.30; 95% CI: 0.09-0.97; p = 0.044), were protective against CRC. Boiled cassava showed a tendency to reduce the likelihood of CRC when consumed ≥ 4 times/week (aOR:0.38; 95% CI: 0.12-1.18) however this did not reach statistical significance (p = 0.093).

CONCLUSIONS

The consumption of boiled beef increases the risk of CRC, while the intake of high-fibre foods may reduce the risk of CRC among Ugandans. We recommend nutritional educational programmes to increase public awareness regarding the protective role of a high-fibre diet and to limit the intake of cooked meat in our Ugandan population.

A Systems Biology Approach to Understand the Racial Disparities in Colorectal Cancer

Racial disparities between Black/African Americans (AA) and White patients in colorectal cancer are an ever-growing area of concern. Black/AA show the highest incidence and have the highest mortality among major U.S. racial groups. There is no definite cause other than possible sociodemographic, socioeconomic, education, nutrition, delivery of healthcare, screening, and cultural factors. A primary limitation in this field is the lack of and small sample size of Black/AA studies. Thus, this study aimed to investigate whether differences in gene expression contribute to this ongoing unanswered racial disparity issue. In this study, we examined transcriptomic data of Black/AA and White patient cohorts using a bioinformatic and systems biology approach. We performed a Kaplan-Meier overall survival analysis between both patient cohorts across critical colorectal cancer signal transduction networks (STN), to determine the differences in significant genes across each cohort. Other bioinformatic analyses performed included PROGENy (pathway responsive genes for activity inference), RNA sequencing differential expression using DESeq2, multivariable-adjusted regression, and other associated Kaplan-Meier analyses. These analyses identified novel prognostic genes independent from each cohort, 176 differentially expressed genes, and specific patient cohort STN survival associations. Despite the overarching limitation, the results revealed several novel differences in gene expression between the colorectal cancer Black/AA and White patient cohorts, which allows one to dive deeper into and understand the behavior on a systems level of what could be driving this racial difference across colorectal cancer. Concretely, this information can guide precision medicine approaches tailored specifically for colorectal cancer racial disparities.

SIGNIFICANCE

The purpose of this work is to investigate the racial disparities in colorectal cancer between Black/AA and White patient cohorts using a systems biology and bioinformatic approach. Our study investigates the underlying biology of each patient cohort. Concretely, the findings of this study include disparity-associated genes and pathways, which provide a tangible starting point to guide precision medicine approaches tailored specifically for colorectal cancer racial disparities.

Clinicopathological spectrum of colorectal cancer among the population of the KwaZulu-Natal Province in South Africa

Introduction

the burden of colorectal carcinoma (CRC), once considered rare in Africa, may be changing with the disease being increasingly diagnosed and there is a suggestion that age and race influence tumour behaviour. We sought to describe the clinicopathological spectrum of CRC among the different race and age groups in a South African setting.

Methods

analysis of prospectively collected data from an on-going colorectal cancer database, including demographics, clinical presentation, site, staging and grading on all patients enrolled over an 18-year period.

Results

a total of 2232 patients with CRC were accrued over the study period (Africans, 798; Indians, 890; Coloureds, 104; and Whites, 440). Mean age was 57.7 (SD 14.4) but varied considerably by race (p < 0.001) with Africans being significantly younger. Young adults (aged < 40 years) totalled 305 and older patients (aged > 40 years) totalled 1927. The proportion of young patients (< 40 years old) was 28%, 7%, 9% and 3% among Africans, Indian, Coloured and White patients respectively. There were minimal variations in anatomical sub-site distribution. There was no difference in tumour stage between the various races and between older and young adults. Mucinous differentiation was more common in Africans and in young patients and poor differentiation was more common in African patients. Africans had a significantly lower resection rate compared to the other race groups (p < 0.001). Younger patients had a significantly lower resection rate compared to the older age group (p < 0.001).

Conclusion

African patients were the youngest compared to the other race groups. Mucinous differentiation predominated in Africans and young adults. Poor differentiation predominated in Africans. Resection rate was lower for African patients and in young patients.

Familial adenomatous polyposis syndrome with colorectal cancer in two Nigerians: a report of two cases and review of literature

Familial adenomatous polyposis syndrome is a rare condition characterized by the presence of numerous adenomatous polyps in the gastrointestinal tract and associated with risk for colorectal cancer. The disease is scarcely reported in Nigeria and this is the index report in Ilorin. Two cases were clinically diagnosed in our facility. They both presented with gastrointestinal bleeding and numerous rectal and colonic polyps were identified at colonoscopy. Histological examination of the polyps in both cases revealed features in keeping with adenomatous polyps. This report highlights the occurrence of this precancerous condition.

Gut microbiome of Moroccan colorectal cancer patients

Although colorectal cancer is the third leading cause of death in Morocco, there are no studies of the microbiome changes associated with the disease in the Moroccan population. The aim of our study was to compare the stool microbiome of Moroccan cancer patients with healthy individuals. We analyzed the microbiome composition of samples from 11 CRC patients and 12 healthy individuals by 16S rRNA amplicon sequencing. Principal coordinate analysis of samples revealed defined cancer versus healthy clusters. Our findings showed that cancer samples had higher proportions of Firmicutes (T = 50.5%; N = 28.4%; p = 0.04), specifically of Clostridia (T = 48.3%; N = 19.0%; p = 0.002), and Fusobacteria (T = 0.1%; N = 0.0%; p = 0.02), especially of Fusobacteriia (T = 0.1%; N = 0.0%; p = 0.02), while Bacteroidetes were enriched in healthy samples (T = 35.1%; N = 62.8%; p = 0.06), particularly the class Bacteroidia (T = 35.1%; N = 62.6%; p = 0.06). Porphyromonas, Clostridium, Ruminococcus, Selenomonas, and Fusobacterium were significantly overrepresented in diseased patients, similarly to other studies. Predicted functional information showed that bacterial motility proteins, flagellar assembly, and fatty acid biosynthesis metabolism were significantly overrepresented in cancer patients, while amino acid metabolism and glycan biosynthesis were overrepresented in controls. This suggests that involvement of these functional metagenomes is similar and relevant in the carcinogenesis process, independent of the origin of the samples. Results from this study allowed identification of bacterial taxa relevant to the Moroccan population and encourages larger studies to facilitate population-directed therapeutic approaches.

Emergence of Colorectal Cancer in West Africa: Accepting the Inevitable

It seems not too long ago that colon and rectal cancer is a "rare" disease in rural Africa; however, over the last 30 years in West Africa, published evidence has shown decade by decade increases in the incidence of colorectal cancer (CRC). Therefore, CRC should now be accepted as a recognized disease in native Africans; nevertheless, we must acknowledge that the incidence is a fraction of what obtains in the developed countries of Europe and America. This presentation will attempt to examine the emergence of CRC within the West African axis over the last four decades.

Gastrointestinal endoscopy in Nigeria--a prospective two year audit

Introduction

Gastrointestinal (GI) endoscopy is currently performed by different specialties. Information on GI endoscopy resources in Nigeria is limited. Training, cost, availability and maintenance of equipment are some unique challenges. Despite these challenges, the quality and completion rates are important.

Methods

Prospective audit of endoscopic procedures by an endoscopist in a Nigerian hospital over a 24 month period.

Results

One hundred and ninety endoscopic procedures were performed in 187 patients (109 male, 78 female) by a surgeon during this period. Mean age was 47.6 years (range 17 - 90 years). All patients were symptomatic. One hundred and twenty-two procedures (64.2%) were upper GI endoscopy, 52 (27.4%) colonoscopy and 16 (8.4%) sigmoidoscopy. Majority of endoscopies 182 (95.8%) were performed electively and only 7 (3.7%) were therapeutic. Upper GI endoscopy findings included 14 (11.5%) cases of peptic ulcer disease, 5 complicated by gastric outlet obstruction, and 21 (17.3%) cases of upper gastrointestinal cancer. Lower gastrointestinal endoscopy findings included 7 cases of polyps, 3 cases of colorectal cancer and 2 cases of diverticulosis. Commonest lesion on lower GI endoscopy was haemorrhoids (41.7%). Adjusted caecal intubation was 81.4% for colonoscopies performed. Overall adenoma detection rate for male and female patients were 18.2% and 5.3% respectively; in patients over 50 years these were 6.3% and 14.3%. Two complications, rupture of oesophageal varices, and respiratory arrest in bulbar palsy patient occurred.

Conclusion

An endoscopist can perform GI endoscopy effectively in developing countries like Nigeria but attention to equipment need and training is important.