Meat and colorectal cancer in Middle Eastern and North African countries: update of literature review

The burden of colorectal cancer attributable to dietary risk in Middle East and North African from 1990 to 2019

The incidence of colorectal cancer (CRC) is increasing in low- and middle-income countries. This study aimed to estimate the burden of CRC attributable to nutritional risk in the Middle East and North Africa (MENA) region. The GBD 2019 methods were used to estimate age-standardized mortality rates (ASMRs) and disability-adjusted life-years (DALYs) in 2019 and over the past three decades. We evaluated the 30-year trend in DALYs and mortality rates from nutrition-related risks of CRC, from 1990 to 2019 by sex and age groups in 21 countries in the MENA region. The rate of DALYs/100,000 due to diet-related risks for CRC in 2019 was 79.71 (95% UI: 56.79, 98.44) and 65.16 (95% UI: 45.86, 80.95) in men and women, respectively. The percent changes of DALYs/100,000 in men and women were 8.15% and 2.50%, respectively, between 1990 and 2019. The percent changes in ASMRs in men and women were 8.32% and 3.44%, respectively. The highest DALYs and ASMRs were observed in both sexes in the age group 75-79 years and above. The highest percent changes in DALYs/100,000 and ASMRs were observed between 1990 and 2019 in Afghanistan, Egypt, Iran, Iraq, Lebanon, Libya, Morocco, Palestine, Qatar, Saudi Arabia, Sudan and Yemen. DALYs and ASMRs attributed to dietary risk for CRC increased in 21 countries in the MENA region from 1990 to 2019. A modified diet with more fiber, dairy products and less red meat intake is a highly recommended strategy for prevention CRC.

Prevalence and patterns of mutations in RAS/RAF/MEK/ERK/MAPK signaling pathway in colorectal cancer in North Africa

Background

Our review discuss (i) the findings from analyzed data that have examined KRAS, NRAS and BRAF mutations in patients with colorectal cancer (CRC) in North Africa and to compare its prevalence with that shown in other populations and (ii) the possible role of dietary and lifestyle factors with CRC risk. 

Methods

Using electronic databases, a systematic literature search was performed for the KRAS, NRAS, and BRAF mutations in CRC patients from Morocco, Tunisia, Algeria and Lybia. 

Results

Seventeen studies were identified through electronic searches with six studies conducted in Morocco, eight in Tunisia, two in Algeria, and one in Libya. A total of 1843 CRC patients were included 576 (31.3%) in Morocco, 641 (34.8%) in Tunisia, 592 (32.1%) in Algeria, and 34 (1.8%) in Libya. Overall, the average age of patients was 52.7 years old. Patients were predominantly male (56.6%). The mutation rates of KRAS, NRAS and BRAF were 46.4%, 3.2% and 3.5% of all patients, respectively. A broad range of reported KRAS mutation frequencies have been reported in North Africa countries. The KRAS mutation frequency was 23.9% to 51% in Morocco, 23.1% to 68.2% in Tunisia, 31.4% to 50% in Algeria, and 38.2% in Libya. The G12D was the most frequently identified KRAS exon 2 mutations (31.6%), followed by G12V (25.4%), G13D (15.5%), G12C (10.2%), G12A (6.9%), and G12S (6.4%). G12R, G13V, G13C and G13R are less than 5%. There are important differences among North Africa countries. In Morocco and Tunisia, there is a higher prevalence of G12D mutation in KRAS exon 2 (≈50%). The most frequently mutation type in KRAS exon 3 was Q61L (40%). A59T and Q61E mutations were also found. In KRAS exon 4, the most common mutation was A146T (50%), followed by K117N (33.3%), A146P (8.3%) and A146V (8.3%).

Conclusion

KRAS mutated CRC patients in North Africa have been identified with incidence closer to the European figures. Beside established anti-CRC treatment, better understanding of the causality of CRC can be established by combining epidemiology and genetic/epigenetic on CRC etiology. This approach may be able to significantly reduce the burden of CRC in North Africa.

Total, red and processed meat consumption and human health: an umbrella review of observational studies

Meat consumption has represented an important evolutionary step for humans. However, modern patterns of consumption, including excess intake, type of meat and cooking method have been the focus of attention as a potential cause of rise in non-communicable diseases. The aim of this study was to investigate the association between total, red and processed meat with health outcomes and to assess the level of evidence by performing a systematic search of meta-analyses of prospective cohort studies. Convincing evidence of the association between increased risk of (i) colorectal adenoma, lung cancer, CHD and stroke, (ii) colorectal adenoma, ovarian, prostate, renal and stomach cancers, CHD and stroke and (iii) colon and bladder cancer was found for excess intake of total, red and processed meat, respectively. Possible negative associations with other health outcomes have been reported. Excess meat consumption may be detrimental to health, with a major impact on cardiometabolic and cancer risk.