The evidence gap between alcohol consumption and oesophageal squamous cell carcinoma in east Africa
Authors: Jin Zhang, Chaoyang Liang, Wenquan Niu
Journal: The Lancet Global Health (2022)

In the largest multicentre association study to date targeting oesophageal squamous cell carcinoma (ESCC) from east Africa, Daniel Middleton and colleagues (February, 2022)1Middleton DRS Mmbaga BT Menya D et al.Alcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and Malawi.Lancet Glob Health. 2022; 10: e236-e245Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar substantiate the contribution of alcohol consumption to risk of ESCC. In the era of precision oncology, understanding internal and external carcinogens behind ESCC could be a major requirement for risk assessment and stratification, as well as for optimal management of individuals with or at high risk of oesophageal cancer. With regard to the public health importance of this study,1Middleton DRS Mmbaga BT Menya D et al.Alcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and Malawi.Lancet Glob Health. 2022; 10: e236-e245Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar two aspects merit special consideration. First, it is widely recognised that a genetic element underlies ESCC carcinogenesis and alcohol metabolism, and populations of various origins can have different linkage disequilibrium patterns.2Boffetta P Hashibe M Alcohol and cancer.Lancet Oncol. 2006; 7: 149-156Summary Full Text Full Text PDF PubMed Scopus (665) Google Scholar, 3Suo C Yang Y Yuan Z et al.Alcohol intake interacts with functional genetic polymorphisms of aldehyde dehydrogenase (ALDH2) and alcohol dehydrogenase (ADH) to increase esophageal squamous cell cancer risk.J Thorac Oncol. 2019; 14: 712-725Summary Full Text Full Text PDF PubMed Scopus (24) Google Scholar In this study,1Middleton DRS Mmbaga BT Menya D et al.Alcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and Malawi.Lancet Glob Health. 2022; 10: e236-e245Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar participants from Kenya, Tanzania, and Malawi represented over 16 ethnicities, with almost no overlap in ethnicity between each country. Evidence exists to suggest that a polymorphism could be in close linkage with another nearby causal variant in one ethnic group but not in another.4Yu K Zhang J Zhang J et al.Methionine synthase A2756G polymorphism and cancer risk: a meta-analysis.Eur J Hum Genet. 2010; 18: 370-378Crossref PubMed Scopus (61) Google Scholar It is reasonable to speculate that ethnicity-specific heterogeneity in genomes might undermine the contribution of alcohol consumption to ESCC risk. The current confusion over whether or not alcohol is an ESCC carcinogen would become clear, pending further consideration of genetic heterogeneity across ethnicities. Additionally, given that hundreds of participants from only three countries were analysed in this study,1Middleton DRS Mmbaga BT Menya D et al.Alcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and Malawi.Lancet Glob Health. 2022; 10: e236-e245Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar it seems premature to translate these regional findings to east Africa. Second, it is well known that alcohol consumption and cigarette smoking often occur together. As reported by Sewram and colleagues,5Sewram V Sitas F O'Connell D Myers J Tobacco and alcohol as risk factors for oesophageal cancer in a high incidence area in South Africa.Cancer Epidemiol. 2016; 41: 113-121Crossref PubMed Scopus (27) Google Scholar alcohol consumption and tobacco use are major risk factors for oesophageal cancer in South Africa. Although Middleton and colleagues1Middleton DRS Mmbaga BT Menya D et al.Alcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and Malawi.Lancet Glob Health. 2022; 10: e236-e245Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar adjusted for smoking while modelling, we suggest investigation into the interaction between alcohol consumption and tobacco use because statistical adjustment alone could be insufficient. We declare no competing interests. The evidence gap between alcohol consumption and oesophageal squamous cell carcinoma in east Africa – Authors' replyWe welcome the comments by Jin Zhang and colleagues on our study,1 which reported the strong role of alcohol consumption in oesophageal squamous cell cancer (ESCC) in east Africa. Our findings, which showed that alcohol consumption was a risk factor for ESCC, are consistent with the IARC monographs.2 In Kenya and Tanzania, we found that a large proportion of male patients with ESCC was attributable to alcohol consumption. Public health actions to reduce harmful alcohol consumption will benefit not only cancer prevention but also prevention of other NCDs and alcohol-associated harms in society. Full-Text PDF Open AccessAlcohol consumption and oesophageal squamous cell cancer risk in east Africa: findings from the large multicentre ESCCAPE case-control study in Kenya, Tanzania, and MalawiAlcohol appears to be a substantial contributor to ESCC risk in east Africa, particularly among men, and a large fraction of ESCC could be prevented by cessation or reduction of alcohol consumption. Future studies should consider independent ascertainment of alcohol intake to assess the potential of under-reporting in Malawi. Full-Text PDF Open Access