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Purpose Age-standardized incidence rates for esophageal cancer (EC) in East Africa have been reported as disproportionately high compared with the worldwide incidence of nine per 100,000 population. This study aimed to characterize EC cases seen at Muhimbili National Hospital and Ocean Road Cancer Institute in Dar es Salaam, Tanzania. Methods Demographic, clinical, and treatment variables were abstracted from charts of patients who received care for a diagnosis of EC at one or both institutions between 2011 and 2013. Categorical data were summarized as frequency counts and percentages. Continuous data were presented as medians and ranges. To compare men and women, Pearson’s χ2 and two-sample t tests were applied. Results Seven hundred thirty-eight unique cases of EC were identified, of whom 68% were men and the median age was 60 years (range, 19 to 95 years). Notably, 93 cases (13%) were ≤ 40 years old at diagnosis. Squamous cell carcinoma was the dominant histology, comprising 90% of cases with documented histopathology. However, 34% of cases with a diagnosis of EC were not pathologically confirmed. The stage was documented as locoregional in 4% of cases, locally advanced in 20% of cases, metastatic in 14% of cases, and unknown in 63% of cases. Of 430 patients who received treatment at Ocean Road Cancer Institute, 76% were treated with radiation, 44% were treated with chemotherapy, 3% underwent a cancer-related surgical procedure, and 10% of cases received no cancer-directed therapy. The median overall survival for all patients was 6.9 months (95% CI, 5.0 to 12.8), regardless of stage at presentation. Conclusion Between 2011 and 2013, cases of EC represented a large clinical burden at both institutions.

Background: East Africa is affected by a disproportionately high burden of esophageal squamous cell carcinoma (ESCC). Methods: We conducted an incident case–control study in Dar es Salaam, Tanzania with 1:1 matching for gender and age. A questionnaire evaluated known and putative risk factors for ESCC. Cochran–Mantel–Haenszel and multivariable conditional logistic regression analyses were applied to evaluate associations with ESCC risk, with adjustment for geographic zone. Results: Of 471 cases and 471 controls, the majority were male (69%); median ages were 59 and 55, respectively. In a multivariable logistic regression model, a low International Wealth Index (IWI) score [OR 2.57; 95% confidence interval (CI), 1.41–4.68], former smoking (OR 2.45; 95% CI, 1.46–4.13), second-hand smoke in the household (OR 1.67; 95% CI, 1.01–2.77), daily spicy chilies (OR 1.62; 1.04–2.52), and daily salted foods (OR 2.02; 95% CI, 1.06–3.85) were associated with increased risk of ESCC. Daily consumption of raw greens (OR 0.36; 95% CI, 0.16–0.80), fruit (OR 0.47; 95% CI, 0.27–0.82), and smoked fish (OR 0.31; 95% CI, 0.15–0.66) were protective. Permanent residence in the Central (OR 5.03; 95% CI, 2.16–11.73), Northern-Lake (OR 2.40; 95% CI, 1.46–3.94), or Southern Highlands zones (OR 3.18; 95% CI, 1.56–6.50) of Tanzania were associated with increased risk compared with residence in the Eastern zone. Conclusions: Low IWI score, smoke exposure(s), geographic zone, and dietary factors were associated with risk for ESCC in Tanzania. Impact: These findings will inform the development of future hypothesis-driven studies to examine risk factors for the high burden of ESCC in East Africa. See related commentary by McCormack et al., p. 248

PURPOSE Esophageal cancer (EC) is one of the most common cancers in East Africa; however, risk factors that underly the high incidence in this region are not well understood. We aimed to investigate the association between exposure to specific alcohol subtypes and EC in Tanzania. METHODS We performed a secondary analysis of data from a hospital-based, case-control study conducted at Muhimbili National Hospital and Ocean Road Cancer Institute in Dar es Salaam, Tanzania. Cases of EC were identified between 2014 and 2016. Hospital controls were identified from patients with nonmalignant conditions and matched 1:1 for gender and age (± 10 years). Interviews were conducted using a survey with culturally relevant and context-specific questions on alcohol and smoking exposure. Conditional logistic regression analyses were applied to evaluate specific associations of potential exposures and EC. RESULTS A total of 473 EC cases and 473 controls were enrolled. Alcohol consumption was reported in 61% and 64% of cases and controls, respectively. Neither ‘current use of alcohol (any type)’, nor ‘ever use’ were associated with EC; however, local brew consumption was associated with increased EC risk (odds ratio [OR], 2.01; 95% CI, 1.53 to 2.66; P < .01). Increased risk was observed with consumption of gongo (OR, 2.91), komoni (OR, 2.41), wanzuki (OR, 2.40), kindi (OR, 3.13), and kangara (OR, 2.86). Smoking increased EC risk; however, it did not significantly modify the association between EC and alcohol subtypes. CONCLUSION This is the first case-control study to report a detailed analysis of alcohol exposures as a potential risk factor for EC in Tanzania. Although combined measures of alcohol use were not found to be associated with EC, several types of locally brewed alcohols emerged as risk factors. Additional research is needed to investigate these findings and examine the carcinogenic role of ingredients and/or contaminants, as well as any interactions with other putative risk factors in this region.

Abstract 96 Purpose The incidence of esophageal cancer in East Africa is disproportionately high. In Tanzania, radiation therapy (RT) is routinely offered for definitive and palliative therapy; however, many patients do not complete RT or die shortly thereafter. The current study aimed to characterize RT treatment patterns in Tanzania and identify predictive factors for RT incompletion. Methods We performed a retrospective chart abstraction for patients with esophageal cancer who were treated with RT at a national referral cancer center in Tanzania from 2011 to 2013. Definitive intent was defined as RT prescriptions with at least 20 fractions with concurrent chemotherapy. Other fractionation regimens were considered palliative. Wilcoxon rank-sum tests, χ2 tests, and logistic regression models were used to identify factors that are associated with palliative or definitive RT incompletion. Results A total of 300 patients—202 male and 98 female patients—were identified with a median age of 60 years (interquartile range [IQR], 48 to 70 years). Nearly 100% (299 of 300) of patients reported dysphagia to solids, and 54% (155 of 288) reported dysphagia to liquids. Median duration of symptoms before presentation was 4 months (IQR, 2 to 6 months), and median time from diagnosis to RT was 1.2 months (IQR, 0.8 to 1.9 months). Overall, 23% were unable to complete RT as a result of death or clinical decompensation. Palliative treatment was administered to 149 patients, and 26% did not complete RT. Definitive treatment was administered to 151 patients, and 20% did not complete RT ( P = .24). Patients younger than age 60 years were less likely to complete palliative RT (odds ratio [OR], 2.4; P = .02). Tobacco use (OR, 2.7; P = .04) and RT initiation within 30 days of diagnosis (OR, 3.5; P = .004) were associated with incomplete definitive RT. Conclusion In Tanzania, approximately 23% of patients die or decompensate before completing esophageal RT. Patients younger than age 60 years were less likely to complete palliative RT. Tobacco use and RT initiation within 30 days of diagnosis was associated with definitive treatment incompletion, perhaps reflecting differences in cancer biology or pace of disease. Additional understanding of how these factors contribute to RT incompletion may inform supportive care resource allocation and patient selection for esophageal RT in Tanzania and similar resource-limited settings. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST No COIs were provided by the authors.

Abstract 89 Purpose Previous studies have characterized geographic clusters of esophageal cancer (EC) in East Africa. Many of the epidemiologic features of EC in this context are shared globally with other clusters, including high rates, male predominance, and squamous cell histology. A unique feature in East Africa is the high proportion of young patients, with a recent case series reporting up to 24% of patients age < 45 years. The aim of the current study was to assess factors that are associated with early-onset EC in Tanzania (TZ). Methods We performed a secondary analysis of a previous case-control study. Patients with newly diagnosed EC were recruited at Muhimbili National Hospital and Ocean Road Cancer Institute in 2014 to 2016. Hospital controls were identified from patients with nonmalignant conditions and matched 1:1 for gender and age ± 10 years. Risk factors were assessed through interviews. Logistic regression was used to estimate age-specific odds ratios (ORs) of EC for exposures across age groups (30 to 44 years, 45 to 59 years, and ≥ 60 years) and for interactions with age. Results A total of 473 cases and 473 controls were enrolled. Median ages were 59 years (range, 30 to 91 years) for cases and 55 years (range, 31 to 88 years) for controls. Among cases, 102 patients (22%) were age 30 to 44 years, 144 patients (30%) were age 45 to 59 years, and 227 patients (48%) were age ≥ 60 years. High household income was protective for those age 30 to 44 years (OR, 0.08; 95% CI, 0.01 to 0.69) and 45 to 59 years (OR, 0.13; 95% CI, 0.04 to 0.45), but not for those age ≥ 60 years (effect modification P = .047). Family history of EC was associated with a higher risk of EC among those age 45 to 59 years (OR, 3.8; 95% CI, 1.02 to 14.47) and age ≥ 60 years (OR, 6.63; 95% CI, 1.50 to 29.37), with no effect among those age 30 to 44 years (effect modification P = .019). Second-hand smoke and infrequent teeth cleaning were also associated with early-onset EC, but did not differ significantly across age groups. Additional factors associated with EC risk across all ages were firewood use (cooking), kerosene use (lighting), work on a maize farm, and in-home grain and nut storage. Protective factors were the regular use of medication, surrogates of high socioeconomic status (TV, radio, refrigerator, indoor toilet, and electricity), and charcoal or gas cooking. Conclusion Multiple exposures were identified as risk factors for early-onset EC in TZ. In age-stratified analyses, household income, second-hand smoke, and poor dental hygiene emerged as possible risk factors, whereas family history of EC had strong associations among the older but not the young age group. Our results suggest that environmental factors may underlie the high incidence of young patients with EC in TZ. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST No COIs from the authors.

Abstract 75 Objective: East Africa has been previously reported as a geographic area with a disproportionately high incidence of squamous cell esophageal cancer (EC). In the setting of an apparent geographic cluster, we sought to identify specific etiologic factors contributing to the high incidence of EC in Tanzania (TZ). Methods: We performed a case-control study to examine possible associations between EC and selected environmental, dietary, and lifestyle factors. Newly diagnosed EC cases were recruited at Muhimbili National Hospital and Ocean Road Cancer Institute during 2014-2015. Hospital controls were identified from patients with non-malignant conditions and matched 1:1 for gender and age ±10 years. The study team conducted in-person interviews. A matched case-control analysis used McNemar’s test with a Mantel-Haenszel estimate for odds ratios (OR). Results: 375 cases and 375 controls were enrolled. 71% of cases and controls were male. Median age was 58 years (range 30-91) for cases and 55 years (range 31-88) for controls. Among cases with a confirmed pathologic diagnosis, squamous cell carcinoma was the most common histology (85%). Liquor consumption (OR 1.84, 95% CI: 1.05-3.22, p=0.04), burning firewood (OR 2.66, 95% CI: 1.88-3.76, pConclusion: Alcohol consumption, firewood and kerosene use as fuel, and surface water consumption merit further investigation as potential etiologic factors contributing to high EC incidence in TZ. Future research will include conducting multivariate analysis with these and other potential risk factors and a genome-wide analysis study using DNA extracted from saliva specimens obtained from cases and controls. Funding: Research support provided by the National Cancer Institute, National Institutes of Health Contract No. HH5N261200800001E. AUTHORS’ DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST: Elia Mmbaga No relationship to disclose Katrina Deardorff No relationship to disclose Beatrice Mushi No relationship to disclose Li Zhang No relationship to disclose William Mgisha No relationship to disclose Aparna Parikh Employment: Genentech Stock or Other Ownership: Genentech Travel, Accommodations, Expenses: Genentech Robert A. Hiatt No relationship to disclose Julius Mwaiselage No relationship to disclose Katherine Van Loon Consulting or Advisory Role: Bayer Company: OncoPlex Diagnostics