The contribution of smoking and smokeless tobacco to esophageal squamous cell carcinoma risk in the African esophageal cancer corridor: results from the ESCCAPE multicenter case-control studies.

Tobacco use is a well-established risk factor for Esophageal Squamous Cell Carcinoma (ESCC) but the extent of its contribution to the disease burden in the African Esophageal Cancer Corridor has not been comprehensively elucidated, including by type of tobacco use. We investigated the contribution of tobacco use (smoking and smokeless) to ESCC in Tanzania, Malawi, and Kenya. Hospital-based ESCC case-control studies were conducted in the three countries. Incident cases and controls were interviewed using a comprehensive questionnaire which included questions on tobacco smoking and smokeless tobacco use. Logistic regression models were used to estimate odds ratios (OR) and their 95% confidence intervals (CI) of ESCC associated with tobacco, adjusted for age, sex, alcohol use, religion, education, and area of residence. 1279 cases and 1345 controls were recruited between Aug 5, 2013, and May 24, 2020. Ever-tobacco use was associated with increased ESCC risk in all countries: Tanzania (OR 3.09, 95%CI 1.83-5.23), and in Malawi (OR 2.45, 95%CI 1.80-3.33) and lesser in Kenya (OR 1.37, 95%CI 0.94-2.00). Exclusive smokeless tobacco use was positively associated with ESCC risk, in Tanzania, Malawi, and Kenya combined (OR 1.92, 95%CI 1.26-2.92). ESCC risk increased with tobacco smoking intensity and duration of smoking. Tobacco use is an important risk factor of ESCC in Tanzania, Malawi and Kenya. This study provides evidence that smoking and smokeless tobacco cessation are imperative in reducing ESCC risk. This article is protected by copyright. All rights reserved.