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.
Factors Associated With Early-Onset Esophageal Cancer in Tanzania: A Case-Control Study
