IARC 60th Anniversary - 19-21 May 2026
Session : 20/05/26 - Posters
Lifestyle and Environmental Risk Factors for Esophageal Squamous Cell Carcinoma: Evidence from the Johannesburg Cancer Study
CHEN W. 1,2,3,4, BRADSHAW D. 5, RAMALIBA T. 6, BABB DE VILLIERS C. 7, NEWTON R. 8, WATERBOER T. 9, MATHEW C. 3,7, MUCHENGETI M. 1,10,11, SITAS F. 5,12,13
1 National Cancer Registry, a Division of the National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2 Strengthening Oncology Services Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 3 Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa; 4 Network for Oncology Research in Africa (NORA), Global Health Working Group, Martin-Luther-University, Halle-Wittenberg, Germany; 5 Burden of Disease Research Unit, South African Medical Research Council, Cape Town, South Africa; 6 Academic Affairs and Research Office, National Health Laboratory Service, Johannesburg, South Africa; 7 Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 8 University of York, York, United Kingdom; 9 Infections and Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 10 Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 11 South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa; 12 UNSW International Centre for Future Health Systems, Sydney, Australia; 13 School of Population Health, University of New South Wales, Sydney, Australia
Background: Esophageal squamous cell carcinoma (ESCC) remains a major cause of cancer mortality in South Africa. Understanding locally relevant and modifiable risk factors is crucial for prevention. This study clarifies the syndemic role of lifestyle and environmental factors, alcohol, tobacco, socioeconomic indicators (rurality and education), and fuel use, in ESCC.
Objectives: To determine whether alcohol, tobacco, and socioeconomic–environmental factors act independently or synergistically to drive esophageal squamous cell carcinoma risk in South Africa, and to clarify whether alcohol meaningfully adds risk beyond that of smoking.
Methods: We analyzed 939 histologically confirmed ESCC cases and 3,089 cancer controls from the Johannesburg Cancer Study. Multivariable logistic regression estimated adjusted odds ratios (aORs), with interaction terms for alcohol–tobacco and sex. Population attributable fractions (PAFs) were calculated using both study-control and national prevalence estimates.
Results: Very high alcohol intake (≥840g ethanol/week) showed a modest independent association with ESCC (aOR = 1.56; 95%CI: 1.14–2.12). Smoking was a strong risk factor, with aOR = 2.82 (95%CI: 2.20–3.62) for ex-smokers and 6.71 (95%CI: 5.15–8.76) for current smokers. Among never-smokers, alcohol showed little dose–response. Among smokers, risks were high across all alcohol levels, with no consistent increase at higher intakes. Additional risks included rural origin or residence (aOR≈1.22–2.38), lower educational attainment (aOR≈1.45–1.69), and use of biomass or other fuels (aOR = 1.50; 95%CI: 1.21–1.87).
Conclusions: In this high-burden setting, tobacco remains the principal modifiable driver of ESCC. Alcohol showed only a modest independent effect, limited to very high intake, and did not increase risk among smokers beyond the high risk from smoking. Socioeconomic and environmental disadvantages cluster with behavioral risks, underscoring a syndemic context. These findings, consistent with prior Johannesburg Cancer Study reports yet offering greater exposure granularity, support targeted prevention strategies focused on smoking cessation, mitigation of hazardous drinking patterns, and reduction of household environmental exposures.
Prevention efforts should focus on smoking cessation, targeted reduction of hazardous drinking, and interventions addressing rural disadvantage, low education, and biomass-fuel exposure. Clinically, these results help prioritize counseling, screening, and public health resources toward exposures that account for the largest share of ESCC risk.