A case-control study of risk factors for colorectal cancer in an African population

Predictive values of an immunological fecal occult blood test for the diagnosis of colorectal cancer compared using colonoscopy in symptomatic patients in Yaounde (Cameroon)

INTRODUCTION

The predictive value of immunological fecal occult blood (iFOB) testing for the screening of colorectal cancer has been well described in the Western world. However, its relevance in Sub-Saharan Africa (SSA) is not well evaluated. It could be altered by the other causes of lower gastrointestinal bleeding such as parasitic infections. The aim of this study was to highlight the performance of an iFOB test for the prediction of colorectal cancer (CRC) during colonoscopy in SSA.

METHODOLOGY

We conducted an analytical cross-sectional study in two digestive endoscopic centers of Yaoundé (Cameroon) from the 1st July to the 31 November 2022. Patients presenting with an indication for colonoscopy without any overt gastrointestinal bleeding were included. Sociodemographic and clinical data were collected. All consenting patients underwent a qualitative immunologic occult test through the iFOB test before colonoscopy. Data were analyzed using SPSS version 23.0 software. The performance of the iFOB test for the diagnosis of CRC during colonoscopy was evaluated in terms of sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

We included 103 patients during the study period with a male predominance and a sex ratio of 1.7. The median age [IQR] was 52 [38-65] years (range 1 - 84 years). The most common colonoscopic lesions were polyps in 23 patients (22.3%), CRC in 17 patients (16.5%) and hemorrhoids in 15 patients (14.6%). Patients testing positive for iFOB test accounted for 43.7% (45 patients). Among these patients, 31.1% (14 patients) had a CRC. The Se of the occult blood test for CRC detection was calculated to be 82.3% (95%CI: 56.7-96.2); the Sp was 63.9% (95% CI: 53-74); the PPV was 31.1% (95% CI: 24-39) and the NPV was 94.8% (95% CI: 86.6-98.1).

CONCLUSION

The iFOB test has a good NPV, but a poor PPV for the diagnosis of CRC in our study.

Is the incidence rate of colorectal cancer increasing in Mozambique?

Background

Colorectal cancer (CRC) is a significant global health concern, ranking as the third most common cancer and the second leading cause of cancer-related deaths. However, in Africa, CRC is the fifth most common invasive malignancy. Limited data hinder our understanding of the evolving burden of CRC in sub-Saharan Africa. This study explores CRC trends in Mozambique, utilising data from population-based oncological registries.

Methods

CRC data were gathered from Beira and Maputo population-based cancer registries, along with supplementary information from pathology-based and hospital-based registries. Comparative analyses were performed across different time periods, focusing on trends and epidemiological characteristics.

Results

Incidence rates of CRC in Maputo and Beira were relatively low historically. However, data from recent years showed an increase, especially in age groups above 50. Analyses from pathology-based and hospital-based registries affirmed the rising trend. The age-standardised incidence rate in Maputo (2015-2017) was 3.17 for males and 2.55 for females. Beira exhibited increasing rates between 2009 and 2020, particularly in individuals aged 50 and above.

Conclusion

The study reveals an emerging burden of CRC in Mozambique, challenging the perception of low incidence. The rising trend underscores the necessity for tailored interventions, emphasizing early diagnosis, preventive strategies, and investments in healthcare infrastructure to address the increasing CRC burden in the region.

Colorectal Cancer Incidence in Iran Based on Sex, Age, and Geographical Regions: A Study of 2014-2017 and Projected Rates to 2025

BACKGROUND

While there has been extensive research on colorectal cancer (CRC) incidence and its associated factors in Iran, a significant gap exists in studies predicting its future trends. Our study aimed to thoroughly report CRC incidence across Iran from 2014 to 2017, by sex, age, and geographical regions, and provide a projection for 2025.

METHODS

This retrospective study utilized data from the Iranian National Population-based Cancer Registry (INPCR). Patients with the International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3) codes C18 to C21 were included. The age-standardized incidence rate (ASR), was calculated per 100000 individuals annually, and crude incidence rates were retrieved for various demographic groups and years.

RESULTS

Between 2014 and 2017, a total of 43580 new CRC cases (55.96% males) were registered. Men exhibited an ASR of 134.45, while women's ASR was 94.85. The highest ASRs were observed in Tehran, Qom, and Ilam (18.99, 18.26, and 18.06, respectively). Incidence rates surpassed 20 after age 50 for both genders, reaching their peak within the 80-84 age group. Adenocarcinoma was the most frequent histological type of CRC in nearly all provinces. Case numbers and ASRs are projected to continuously rise until 2025, with a predominance of male cases.

CONCLUSION

The anticipated increase in CRC incidence in Iran emphasizes the need for additional studies to better identify risk factors. Furthermore, implementing screening programs is recommended for individuals at a higher risk of CRC, including men, the elderly population, and those residing in regions with a notable prevalence of CRC.

Colorectal cancer disease profile and treatment patterns at an urban tertiary hospital in Rwanda

Background

The incidence of colorectal cancer (CRC) in sub-Saharan Africa (SSA) is rising, due to improving cancer registration efforts on one hand and an increasing westernisation of diets and lifestyle on the other as well as increasing rates of comorbidities.

Methods

We present data for the clinical characteristics, pathology, treatments received, and survival outcomes of patients diagnosed with CRC at King Faisal Hospital (KFH) between January 2019 and May 2023. KFH is an urban tertiary hospital in Rwanda that provides chemotherapy and surgery to cancer patients. The data were extracted from electronic medical records, imaging and histopathology reports from the patient's time of diagnosis. We plotted Kaplan-Meier estimation of survival, defined as the time from presentation to death, within the study period (2019-2023).

Results

Seventy-four patients diagnosed with CRC with complete information were identified in the KFH oncology records. The mean age at diagnosis was 54.6 years, with ages ranging between 22 and 81 years. At diagnosis, 24 (32.4%) patients were less than 50 years old and 29 (39.2%) were females. The rectum (36.5%) was the most common tumour location, and 58.1 tumours were left-sided. Most patients presented with Stage III (41.9%) or IV (35.1%) disease. Adenocarcinoma was the most common histological type (98.6%) including adenocarcinoma not otherwise specified (NOS) (86.5%), mucinous adenocarcinoma (10.8%), signet ring cell carcinoma (1.4%) and followed by squamous cell carcinoma (1.4%). In terms of treatment, 19 (25.7%) patients received only chemotherapy, 43 (58.1%) patients received neo-adjuvant or adjuvant chemotherapy, 9 (12.2%) of patients received both neo-adjuvant and adjuvant chemotherapy, 49 patients (66.2%) underwent surgery and 17 (23%) patients also received radiation. At the end of the follow up period, 63 (85.1%) patients remained in surveillance, 10 (13.5%) patients died, and 1 (1.3%) patient was lost to follow up. Mean overall survival was 45.5 (SD ± 2.0) months.

Conclusion

CRC patients presented at an advanced stage and required complex treatment regimens at KFH. Further epidemiologic and molecular research is needed to characterise CRC incidence and presentation at a national level in Rwanda as increasing westernisation continues to change the face of CRC in urban areas of SSA.

Clinicopathological characteristics and its association with digestive system tumors of 1111 patients with Schistosomiasis japonica

Schistosomiasis japonicum can cause different degrees of organ damage and complex human immune pathological reactions, which often invade the intestine and liver. The purpose of this study was to explore the pathological types and pathological changes of Schistosomiasis and their correlation with some digestive system tumors. Hematoxylin eosin staining was performed on the diseased tissues of 1111 Schistosomiasis cases. We counted the deposition sites of Schistosoma eggs, analyzed the pathological characteristics, and compared the clinicopathological characteristics of Schistosomiasis associated digestive system tumors and non-Schistosomiasis digestive system tumors. We found that Schistosoma japonicum can cause multi organ and multi system damage, with 469 cases of inflammation, 47 cases of adenoma, and 519 cases of adenocarcinoma. Other types include cysts, stromal tumors, malignant lymphomas, and neuroendocrine tumors. Schistosomiasis associated tumors, including gastric cancer, liver cancer, colon cancer and rectal cancer, were compared with non-Schistosomiasis tumors. There were significant differences in age, gender and tumor differentiation between the two groups. Our study shows Schistosomiasis is a systemic disease, causing multiple organ and system damage in the human body. Its clinicopathological types are diverse, and there may be a pathological change process of "Inflammation-adenoma-carcinoma". Schistosomiasis associated digestive system tumors differ from non-Schistosomiasis tumors in some clinicopathological features.

Temporal and spatial analyses of colorectal cancer incidence in Yogyakarta, Indonesia: a cross-sectional study

We aimed to explore the district-level temporal dynamics and sub-district level geographical variations of colorectal cancer (CRC) incidence in the Special Region of Yogyakarta Province. We performed a cross-sectional study using data from the Yogyakarta population-based cancer registry (PBCR) comprised of 1,593 CRC cases diagnosed in 2008-2019. The age-standardized rates (ASRs) were determined using 2014 population data. The temporal trend and geographical distribution of cases were analysed using joinpoint regression and Moran's I statistics. During 2008-2019, CRC incidence increased by 13.44% annually. Joinpoints were identified in 2014 and 2017, which were also the periods when annual percentage change (APC) was the highest throughout the observation periods (18.84). Significant APC changes were observed in all districts, with the highest in Kota Yogyakarta (15.57). The ASR of CRC incidence per 100,000 person- years was 7.03 in Sleman, 9.20 in Kota Yogyakarta, and 7.07 in Bantul district. We found a regional variation of CRC ASR with a concentrated pattern of hotspots in the central sub-districts of the catchment areas and a significant positive spatial autocorrelation of CRC incidence rates in the province (I=0.581, p<0.001). The analysis identified four high-high clusters sub-districts in the central catchment areas. This is the first Indonesian study reported from PBCR data, showing an increased annual CRC incidence during an extensive observation period in the Yogyakarta region. A heterogeneous distribution map of CRC incidence is included. These findings may serve as basis for CRC screening implementation and healthcare services improvement.

Large Bowel Perforation in Patients with Colorectal Cancer: A South African Perspective

Introduction

Large bowel perforation (LBP) occurs in up to 10% of colorectal cancer (CRC) patients and is a potential surgical emergency. Data on LBP in CRC patients from resource-limited countries are required to improve the management of this condition in these settings. Our study aimed to describe LBP amongst CRC patients in KwaZulu-Natal, South Africa.

Materials and Methods

This was a descriptive sub-analysis of LBP data from an ongoing CRC registry. This study explores free and contained perforations and describes LBP characteristics, surgical management, histological findings, overall survival, and CRC recurrence.

Results

Ninety-four out of 2523 CRC patients had LBP (3.7%). The median age was 53.0 years (interquartile range: 43.0-64.0). The male-to-female ratio was 1.4:1. Thirty-three patients (35.1%) had a coexisting bowel obstruction. Tumor site perforations occurred in 87 patients (92.6%) and were mostly in the sigmoid colon (36.2%). Perforations were contained in 77 patients (81.9%). Eighty-nine patients (94.7%) underwent resection (elective resection: 76/89 patients, 85.4%). The post-operative inpatient mortality rate was 2.2%. Most patients had Stage III CRC (46 patients, 48.9%) and moderately differentiated tumors (77 patients, 81.9%). Overall survival at 12 months following CRC diagnosis was 55.4%. The early recurrence rate for CRC disease was 5.4%.

Conclusion

Tumor site perforations predominated, and most were contained. Patients were younger when compared with the international literature. We reaffirm that diastatic-free and contained perforations are two distinct clinical entities.

Risk Factors for Colorectal Adenocarcinoma in an Indigenous Population in East Africa

Introduction

The incidence of colorectal cancer (CRC) is increasing in East Africa. Changes in lifestyle and dietary changes, particularly alcohol consumption, smoking, and consumption of cooked meats with a reduction in fibre in the diet may be responsible. The objective of our study was to determine the risk factors responsible for CRC in Uganda.

Methods

We recruited 129 participants with histologically proven colorectal adenocarcinoma and 258 control participants from four specialized hospitals in central Uganda from 2019 to 2021. Controls were block matched for age (±5 years) and sex of the case participants. The risk factor variables included; area of residence, tribe, body mass index (BMI), smoking, alcohol consumption and family history of gastrointestinal cancer. We used conditional or ordinal logistic regression to obtain crude and adjusted odds ratios for risk factors associated with CRC.

Results

In bivariate analysis, case participants were more likely to be associated with urban residence (cOR:62.11; p<0.001); family history of GI cancer (cOR: 14.34; p=0.001); past smokers (cOR: 2.10; p=0.080); past alcohol drinkers (cOR: 2.35; p=0.012); current alcohol drinkers (cOR: 3.55; p<0.001); high BMI 25–29.9 kg/m² (cOR: 2.49; p<0.001); and high BMI ≥30kg/m² (cOR: 2.37; p=0.012). In the multivariate analysis, urban residence (aOR: 82.79; p<0.001), family history of GI cancer (aOR: 61.09; p<0.001) and past smoking (aOR: 4.73; p=0.036) were independently associated with a higher risk of developing CRC.

Conclusion

A family history of gastrointestinal cancer was a risk factor for CRC. While population-based CRC screening may not be feasible in low income-countries, targeted CRC screening for first-degree relatives with CRC should be considered in East Africa. Molecular genetic studies need to be carried out to determine the role of hereditary factors in our population. Prevention strategies should be adopted to avoid smoking in our population which was associated with an increased risk of CRC.

Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.

Interactions between the environmental and human microbiota in the preservation of health and genesis of disease: symposium report

PURPOSE OF REVIEW

The purpose of this symposium was to bring thought leaders in the microbiome from the west to Africa to share their unique experiences with African investigators in order to build the foundations for scientifically rigorous explorations into the African human and environmental microbiome that may explain why disease patterns are different in Africa where the chief killers are infectious diseases, whereas noncommunicable diseases (NCDs) are the major threat to healthcare resources in the developed world.

RECENT FINDINGS

The application of new high throughput technologies to the investigation of the microbiome and its metabolome has revealed mechanisms whereby a traditional African high fiber diet can suppress NCDs which include colon cancer, inflammatory bowel diseases, obesity, type 2 diabetes and atherosclosis. There is concern that with migration and westernization, NCDs are becoming more common in Africa and that food security is becoming impaired by unbalanced obesogenic foods rather than inadequate food intake.

SUMMARY

There is an urgent need for the formation of combined African-Western research programs to identify what is good and bad in the African diet-microbiome axis to develop strategies to prevent the incidence of NCDs rising to western levels in Africa, at the same time offering novel prevention strategies against the #1 healthcare threat in the developed world.

Spatiotemporal Trends of Colorectal Cancer Mortality Due to Low Physical Activity and High Body Mass Index From 1990 to 2019: A Global, Regional and National Analysis

Background: Understanding the spatiotemporal trends of colorectal cancer (CRC) deaths caused by low physical activity (LPA) and high body mass index (BMI) is essential for the prevention and control of CRC. We assessed patterns of LPA and high BMI-induced CRC deaths from 1990 to 2019 at global, regional, and national levels.

Methods: Data on CRC deaths due to LPA and high BMI was downloaded from the Global Burden of Disease 2019 Study. We calculated estimated annual percentage change (EAPC) to quantify spatiotemporal trends in the CRC age-standardized mortality rate (ASMR) due to LPA and high BMI.

Results: In 2019, CRC deaths due to LPA and high BMI were estimated as 58.66 thousand and 85.88 thousand, and the corresponding ASMRs were 0.77/100,000 and 1.07/100,000, with EAPCs of−0.39 [95% confidence interval (CI):−0.49,−0.29] and 0.64[95% CI: 0.57, 0.71] from 1990 to 2019 respectively. Since 1990, the ASMR of CRC attributable to LPA and high BMI has been on the rise in many geographic regions, especially in low middle and middle sociodemographic index (SDI) regions. Thirteen countries had a significant downward trend in CRC ASMR attributed to LPA, with EAPCs < −1. And, only 4 countries had a significant downward trend in CRC ASMR attributable to high BMI, with EAPCs < −1. Countries with a higher baseline burden in 1990 and a higher SDI in 2019 had a faster decline in ASMR due to high BMI and LPA.

Conclusions: The burden of CRC caused by LPA and high BMI is on the rise in many countries. Countries should adopt a series of measures to control the local prevalence of obesity and LPA in order to reduce disease burden, including CRC.

Urbanization Levels and Its Association with Prevalence of Risk Factors and Colorectal Cancer Incidence

BACKGROUND

Colorectal cancer is one of the most common cancers in the world. This study aimed to determine the relationship between risk factors and the incidence of colorectal cancer in Urbanization levels in Iran.

METHODS

This was a population-based study. Urbanization levels were determined using the census data of the Statistical Center in 2012. Data on risk factors for colorectal cancer were obtained from the information provided by the Iranian Non-Communicable Disease Control Center and the incidence of colorectal cancer from the data from the National Cancer Registry System. Negative binomial regression analysis was used to determine the relationship between colorectal cancer risk factors and urbanization levels with colorectal cancer incidence. For statistical analysis, SPSS and Stata software were used. A significant level of P≤0.05 was considered.

RESULTS

The relationship between urbanization levels and risk factors with the incidence of colorectal cancer, nutrition Status, tobacco use, and body mass index were not significant. There was a significant relationship between physical activity and incidence at different levels and between levels of urbanization and incidence rate, indicating a lower incidence rate of colorectal cancer at lower levels of urbanization.

CONCLUSION

Colorectal cancer incidence is higher at higher levels of urbanization than lower levels. The difference between regions in terms of urbanization can have in flounce on access to facilities, health service, and counseling opportunities to modify the risk factors and access to proper screening and follow-up care.

Association of Family History and Life Habits in the Development of Colorectal Cancer: A Matched Case-Control Study in Mexico

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers and, as such, is important for public health. The increased incidence of this neoplasm is attributed to non-modifiable controls such as family history and modifiable variable behavioral risk factors involved in lifestyle like diets in Mexico. The presence of these factors is unknown. Therefore, the aim of this study was to evaluate family history and lifestyle factors associated with developing colorectal cancer in a Mexican population. Descriptive statistics and multivariate logistic regression were used to estimate the adjusted odds ratios (OR), as well as the 95% confidence intervals (CI). In this paper, significant differences were demonstrated between cases and controls. A family history of cancer (FHC) increased the probability of CRC [OR = 3.19 (95% CI: 1.81-5.60)]. The area of urban residence was found to be a protective factor compared to the rural area. This was also the case for frequent consumption of fruits [OR = 0.49 (95% CI: 0.28-0.88)], the frequent consumption of beef [OR = 2.95 (95% CI: 1.05-8.26)], pork [OR = 3.26 (95% CI: 1.34-7.90)], and region-typical fried food [OR = 2.79 (95% CI (1.32-5.89)]. These results provide additional evidence supporting the association of some CRC risk factors with family history of cancer, low fruit consumption, high consumption of red meat, and fried foods typical of the region of México. It is important to establish intervention methods, as well as genetic counseling to relatives of patients with CRC.

Awareness of Colorectal Cancer and Associated Factors Among Adult Patients in Jimma, South-West Ethiopia: An Institution-Based Cross-Sectional Study

Background

Colorectal cancer (CRC) is the first commonest diagnosed cancer in men and the fourth commonest in women in Ethiopia. Awareness of CRC and associated factors is crucial in the prevention of CRC. However, there have not been studies about the awareness of CRC and associated factors among adult patients in Ethiopia. Therefore, the study aimed to assess the awareness of CRC and associated factors among adult patients in Jimma, South-West Ethiopia, 2020.

Methods

This institution-based cross-sectional study design was conducted among 422 adult patients. The study respondents were recruited by a systematic random sampling method. The Cancer Awareness Measure questions were used to measure awareness of CRC of adult patients. Descriptive and logistic regression analyses were conducted.

Results

More than half (57.6%) of respondents had low-level awareness of CRC. Respondents who were females (adjusted odds ratio [AOR] = 1.86; 95% CI: 1.26, 2.75), who are residing in urban areas (AOR = .45; 95% CI: .30, .67), who had a monthly income of 3000 Ethiopian Birr and above (AOR = 4.72; 95% CI: 3.11, 7.15), who heard about CRC (AOR = 4.48; 95% CI: 2.90, 6.93), who get information through social media about CRC (AOR = 2.51; 95% CI: 1.18, 5.37), and who had a family history of CRC (AOR = 3.27; 95% CI: 1.45, 7.36) had a high level of awareness of CRC, while those who cannot read and write (AOR = 2.83; 95% CI: 1.49, 5.37) and learn elementary school (AOR = 2.12; 95% CI: 1.15, 3.93) had a low level of awareness of CRC.

Conclusion

This study indicated that awareness of CRC of adult patients was inadequate. Adult patients’ gender, residency, level of education, monthly income, heard about CRC, sources of information about CRC, and a family history of CRC were found to be independent predictors of the awareness of CRC. Therefore, there is a need for health education and awareness campaigns for promoting awareness of CRC of adult patients, and the government should develop policy on CRC prevention and screening program.

Cancer in Africa: The Untold Story

BACKGROUND

Despite rising incidence and mortality rates in Africa, cancer has been given low priority in the research field and in healthcare services. Indeed, 57% of all new cancer cases around the world occur in low income countries exacerbated by lack of awareness, lack of preventive strategies, and increased life expectancies. Despite recent efforts devoted to cancer epidemiology, statistics on cancer rates in Africa are often dispersed across different registries. In this study our goal included identifying the most promising prevention and treatment approaches available in Africa. To do this, we collated and analyzed the incidence and fatality rates for the 10 most common and fatal cancers in 56 African countries grouped into 5 different regions (North, West, East, Central and South) over 16-years (2002-2018). We examined temporal and regional trends by investigating the most important risk factors associated to each cancer type. Data were analyzed by cancer type, African region, gender, measures of socioeconomic status and the availability of medical devices.

RESULTS

We observed that Northern and Southern Africa were most similar in their cancer incidences and fatality rates compared to other African regions. The most prevalent cancers are breast, bladder and liver cancers in Northern Africa; prostate, lung and colorectal cancers in Southern Africa; and esophageal and cervical cancer in East Africa. In Southern Africa, fatality rates from prostate cancer and cervical cancer have increased. In addition, these three cancers are less fatal in Northern and Southern Africa compared to other regions, which correlates with the Human Development Index and the availability of medical devices. With the exception of thyroid cancer, all other cancers have higher incidences in males than females.

CONCLUSION

Our results show that the African continent suffers from a shortage of medical equipment, research resources and epidemiological expertise. While recognizing that risk factors are interconnected, we focused on risk factors more or less specific to each cancer type. This helps identify specific preventive and therapeutic options in Africa. We see a need for implementing more accurate preventive strategies to tackle this disease as many cases are likely preventable. Opportunities exist for vaccination programs for cervical and liver cancer, genetic testing and use of new targeted therapies for breast and prostate cancer, and positive changes in lifestyle for lung, colorectal and bladder cancers. Such recommendations should be tailored for the different African regions depending on their disease profiles and specific needs.

Hereditary, environmental, and dietary risk factors of colorectal cancer: a case-control study in the Algerian East

Colorectal carcinoma (CRC) is the second most common cancer diagnosed in Algeria. The incidence and the mortality rate of CRC have increased so that the nation now ranks third in Africa in both these variables. Many environmental and genetic factors are suspected to play an important role in the development of the disease. This study aimed to identify the risk factors for CRC in Algeria. We performed a case-control study in five Medical Oncology Services in this region: Tebessa, Batna, Annaba, Setif, and Constantine, from 2016 to 2019. Altogether, 200 patients diagnosed with CRC and 200 age-matched controls without any diagnosis of cancer were included. Study participants were interviewed about environmental, dietary, and hereditary risk factors, i.e., family history of cancer, using a questionnaire. Results showed a significant association between high educational level and a decreased risk of CRC. Diagnoses of any cancer or of CRC in first-degree or in second- or third-degree relatives also were significantly associated with CRC risk. Occupational exposures showed a significant link with an increased risk of CRC, as did obesity, alcohol consumption, and passive smoking. Yogurt, cereals, sugar, butter, and margarine consumption were significant protective factors, while cheese, dried fruits, red meat, juice, and fizzy drink consumption was associated with increased risk. Our findings suggest a benefit of public health campaigns to enhance awareness about CRC and to encourage healthy dietary choices and avoidance of non-dietary risk factors.

Polarization of intestinal tumour-associated macrophages regulates the development of schistosomal colorectal cancer

Tumour-associated macrophages (TAMs) can be divided into M1 and M2 TAMs. M2 TAMs play an important role in tumor progression, promoting a pro-angiogenic and immunosuppressive signal in the tumor. Previous studies have shown a correlation between schistosomiasis and colorectal cancer (CRC), but the specific mechanism has not been clarified. The differences between schistosomal CRC and non-schistosomal CRC were explored by analysing the clinicopathological data and survival time prognosis of schistosomal CRC and non-schistosomal CRC patients. The underlying mechanisms leading to the differences were investigated via tissue pathology experiments. Here, we investigated whether TAMs play a role in schistosomal CRC, leading to different clinicopathological features and prognoses in schistosomal CRC and non-schistosomal CRC patients and whether TAMs have a regulatory effect on the development and prognosis of schistosomal CRC. We found that schistosomal CRC and non-schistosomal CRC patients differ in age, sex, TNM staging and prognosis survival. Applying a logistic regression analysis model, the results showed that age, sex, pathological T stage and combined schistosomiasis were independent risk factors for CRC. Prognostic analysis of follow-up patients with schistosomal CRC found that the T stage, M stage and M2 TAMs numbers were independent prognostic factors for overall survival (OS). TAMs are significantly higher in tissues of schistosomal CRC than in non-schistosomal CRC patients, especially M2 TAMs. Studies on schistosomal colorectal tissue found that the expression of M2 TAMs increased with the malignant process of intestinal tissue. In summary, schistosomal CRC and non-schistosomal CRC patients have different clinicopathological features and prognosis, schistosomiasis is a risk factor for CRC and M2 TAMs are independent prognostic factors for OS.

Colorectal Cancer Genetics, Incidence and Risk Factors: In Search for Targeted Therapies

Each year, colorectal cancers (CRCs) affect over a quarter of a million people. The risk of developing CRC in industrialized nations is approximately 5%. When the disease is localised, treatment success rates range from 70-90%; however, advanced CRC has a high mortality rate, consistently ranking in the top three causes of cancer-related deaths. There is a large geographic difference in global distribution, and CRC is predominantly associated with developed countries and a Western lifestyle and diet. As such, the developed world accounts for more than 63% of all cases of CRC. Geographic variations also predict cancer outcomes, which differ between racial and ethnic groups. This variation is due to inequalities in wealth, differences in the exposure to risk factors and barriers to high-quality cancer prevention, early detection and treatment. The aim of this paper was to review CRC in low- and middle-income countries such as South Africa, India, Brazil and China, and compare them with high-income countries such as the United States of America and the United Kingdom. It is important to note that these economically less developed countries, with historically low CRC rates, are experiencing an increased frequency of CRC. The review also discusses biological markers and genetic pathways involved in the development of colorectal cancer. Genes known to be responsible for the most common forms of inherited CRCs have also been identified but more remain to be identified. This would provide more candidate genes to be added to known biomarkers. CRC burden can be controlled through the widespread application of existing knowledge, such as reduced smoking habits, vaccination, early detection and promoting physical activity, accompanied by a healthy diet. An increased understanding of the molecular mechanisms and events underlying colorectal carcinogenesis will enable the development of new targets and therapeutic drugs.

Comparison of the clinicopathological features and prognoses of patients with schistosomal and nonschistosomal colorectal cancer

Patients with schistosomal colorectal cancer (CRC) and nonschistosomal CRC have different clinicopathological features, laboratory test results and survival rates. Long-term infection with schistosomiasis in patients with CRC may affect the pathogenesis and subsequently change the mechanisms of CRC in these patients, resulting in changes in the survival rates of patients with schistosomal and nonschistosomal CRC. In China, the most common type of schistosomiasis is S. japonicum. The present study aimed to investigate the clinicopathological features and prognostic factors of schistosomal and nonschistosomal CRC. A total of 253 patients with schistosomal CRC and 2,885 patients with nonschistosomal CRC were analyzed and their symptoms, clinicopathological features and laboratory test results were retrospectively evaluated. Patients with CRC in the present study underwent radical resection at The First Affiliated Yijishan Hospital of Wannan Medical College between January 2012 and December 2018. A total of 3,138 patients with CRC were enrolled, 253 of whom were patients with schistosomal CRC. Patients were followed-up to examine differences in the 5-year survival rates between patients with schistosomal and nonschistosomal CRC to determine whether schistosomiasis impacted the prognosis of CRC. There were significant differences in age, sex, fecal occult blood positive, pathological T stage, and CA19-9, WBC, RBC and PLT levels between patients with schistosomal CRC and nonschistosomal CRC. For residents in areas with higher levels of schistosomiasis infections, especially middle-aged and elderly males, serum tumor markers and digestive tract endoscopy should be regularly evaluated to detect the presence of digestive tract tumors as early as possible.

Investigation on the hereditary basis of colorectal cancers in an African population with frequent early onset cases

Background

Approximately 25% of colorectal cancer patients in sub-Saharan Africa are younger than 40 years, and hereditary factors may contribute. We investigated the frequency and patterns of inherited colorectal cancer among black Zimbabweans.

Methods

A population-based cross-sectional study of ninety individuals with a new diagnosis of colorectal cancer was carried out in Harare, Zimbabwe between November 2012 and December 2015. Phenotypic data was obtained using interviewer administered questionnaires, and reviewing clinical and pathology data. Cases were screened for mismatch repair deficiency by immunohistochemistry and/or microsatellite instability testing, and for MLH1, MSH2 and EPCAM deletions using multiplex ligation-dependent probe amplification. Next generation sequencing using a 16-gene panel was performed for cases with phenotypic features consistent with familial colorectal cancer. Variants were assessed for pathogenicity using the mean allele frequency, phenotypic features and searching online databases.

Results

Three Lynch syndrome cases were identified: MSH2 c.2634G>A pathogenic mutation, c.(1896+1_1897–1)_(*193_?)del , and one fulfilling the Amsterdam criteria, with MLH1 and PMS2 deficiency, but no identifiable pathogenic mutation. Two other cases had a strong family history of cancers, but the exact syndrome was not identified. The prevalence of Lynch syndrome was 3·3% (95% CI 0·7–9·4), and that of familial colorectal cancer was 5·6% (95% CI, 1·8–12·5).

Conclusions

Identifying cases of inherited colorectal cancer in sub-Saharan Africa is feasible, and our findings can inform screening guidelines appropriate to this setting.

Dietary patterns and colorectal cancer risk in Zimbabwe: A population based case-control study

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Three main dietary patterns in Zimbabwe; traditional African, urban and processed foods.

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Traditional African diet associated with a reduced risk of colorectal cancer.

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No association between colorectal cancer and the urban or processed food patterns.

Background

The rising incidence of colorectal cancer in sub-Saharan Africa may be partly caused by changing dietary patterns. We sought to establish the association between dietary patterns and colorectal cancer in Zimbabwe.

Methods

One hundred colorectal cancer cases and 200 community-based controls were recruited. Data were collected using a food frequency questionnaire, and dietary patterns derived by principal component analysis. Generalised linear and logistic regression models were used to assess the associations between dietary patterns, participant characteristics and colorectal cancer.

Results

Three main dietary patterns were identified: traditional African, urbanised and processed food. The traditional African diet appeared protective against colorectal cancer (Odds Ratio (OR) 0.35; 95% Confidence Interval (CI), 0.21 – 0.58), which had no association with the urban (OR 0.68; 95% CI, 0.43–1.08), or processed food (OR 0.91; 0.58–1.41) patterns. The traditional African diet was associated with rural domicile, (OR 1.26; 95% CI, 1.00–1.59), and a low income (OR1.48; 95% CI, 1.06–2.08). The urbanised diet was associated with urban domicile (OR 1.70; 95% CI, 1.38–2.10), secondary (OR 1.30; 95% CI, 1.07–1.59) or tertiary education (OR 1.48; 95% CI, 1.11–1.97), and monthly incomes of $201–500 (OR 1.30; 95% CI, 1.05–1.62), and the processed food pattern with tertiary education (OR 1.42; 95% CI, 1.05–1.92), and income >$1000/month (OR 1.48; 95% CI, 1.02–2.15).

Conclusion

A shift away from protective, traditional African dietary patterns may partly explain the rising incidence of colorectal cancer in sub-Saharan Africa.

CTLA4 tagging polymorphisms and risk of colorectal cancer: a case-control study involving 2,306 subjects

Background

CTLA4 is a candidate gene which has been implicated in the development of colorectal cancer (CRC).

Patients and Methods

To determine the important role of CTLA-4 polymorphisms on risk of CRC, we genotyped four CTLA-4 tagging polymorphisms and calculated crude/adjusted ORs with their 95% CIs. We recruited 1,003 sporadic CRC cases and 1,303 controls.

Results

The findings suggested that CTLA-4 rs231775 G>A polymorphism increased the risk of CRC (homozygote model: adjusted OR=1.40, 95% CI=1.05-1.87, P=0.022; dominant model: adjusted OR=1.19, 95% CI=1.00-1.41, P=0.047; and recessive model: adjusted OR=1.38, 95% CI=1.05-1.82, P=0.021). In a stratified analysis by site of tumor, this association was also found in colon cancer. We also found that CTLA-4 rs231775 GA/AA genotypes might be associated with an increased risk of CRC in Zhenjiang cohort. In addition, we found the CTLA-4 rs16840252 C>T polymorphism was associated with the risk of colon cancer. Haplotype comparison analysis showed that CTLA-4 G_rs3087243C_rs16840252C_rs733618 A_rs231775, G_rs3087243C_rs16840252T_rs733618A_rs231775, and other haplotypes increased the risk of CRC (P<0.001, <0.001, and 0.002, respectively).

Conclusion

This study evidences an association of CTLA-4 tagging polymorphisms and haplotypes with CRC risk. Additional well-designed studies with large sample sizes are required to confirm our findings.