A Pilot for a Case-Control Study of Esophageal Squamous Cell Carcinoma in Western Kenya

Overview

Background: * Esophageal cancer is the sixth leading cause of cancer deaths worldwide. Two primary cell types, squamous cell carcinoma and adenocarcinoma, account for most cases. Of the two, esophageal squamous cell carcinoma (ESCC) accounts for more than 80 percent of all deaths from esophageal cancer. Many cases occur in certain areas with defined geographic boundaries, including parts of Kenya. * Studies of ESCC in developed countries (such as the United States) suggest that heavy tobacco and alcohol use, poor diet, and low socioeconomic status are the primary risk factors. Males and African Americans are also at higher risk. However, these risk factors do not fully explain the prevalence of cases in several of the identified geographic areas. * ESCC is the most common cancer seen at Tenwek Hospital in western Kenya, and a notable number of patients are 30 years of age or younger. Objectives: * To test the feasibility of a new protocol by recruiting visitors to Tenwek Hospital and volunteers from the general population for study purposes. * To use the new protocol to obtain blood and urine samples from ESCC cases in Tenwek Hospital and from nonpatient volunteers. Eligibility: * Hospital patients and volunteers who live within 50 kilometers of Tenwek Hospital in western Kenya. Design: * All participants will complete a questionnaire and provide blood and urine samples for testing. * The questionnaire will include questions about individual and family medical history, living conditions, lifestyle, habits, and diet. * Blood and urine samples will be collected from all participants after the questionnaire. * Biological samples will be shipped to the United States for further testing. * Treatment will not be offered as part of this study.

This pilot study will assess the feasibility of completing the first formal case-control study to examine etiologic factors for esophageal squamous cell carcinoma (ESCC) in Kenya and will be conducted in Western Kenya, a high-risk area for ESCC. Esophageal cancer causes over 380,000 deaths per year and ranks as the sixth leading cause of cancer death worldwide. Two primary cell types, squamous cell carcinoma and adenocarcinoma, account for most cases. Although the rates of esophageal adenocarcinoma have risen rapidly in the United States and elsewhere, ESCC still accounts for 80% of all esophageal cancer cases in the world. Many of these cases occur in high-risk areas with sharp geographic boundaries within China, Iran, a small region of South America, South Africa, and Kenya. Studies of ESSC in economically developed countries, such as the US, point to smoking tobacco, heavy alcohol drinking, poor diets deficient in fresh fruits and vegetables, and low socioeconomic status as the main etiologic factors. Other independent risk factors may include being male and being African-American. Smoking tobacco and heavy alcohol consumption do not explain the incidence rates in the high-risk regions because these habits are less common and less intensely practiced in these high-risk areas compared to the low risk area. Also, in highrisk areas the incidence rates are similar in men and women despite differences in the rates of tobacco smoking and alcohol drinking. Therefore, it is important to consider a wide range of etiologic factors to explain the high rates of cancer in these populations. Tenwek Hospital is a 300 bed mission hospital located in Bomet District, Rift Valley Province, approximately 200 miles from Nairobi in the west of Kenya. Tenwek serves as a primary health care facility for approximately 400,000 people, and it has become a referral center for a broader population. ESCC is the most common malignancy seen at Tenwek Hospital and the patients show a very unusual age distribution with 10% of cases less than or equal to 30 years of age. We will conduct a pilot for a case-control study of ESCC at Tenwek Hospital, recruiting people that live within 50 km of the hospital. Initial pilot testing showed that neither hospital-visitor controls nor general-population controls were practical control sources. We now plan to test the feasibility of collecting 50 hospital-based non-cancer patient controls. We will then enroll 50 cases and 50 additional hospital-based non-cancer patient controls to test all aspects of our protocol. We will ship the biological samples collected from these individuals to the US and test their suitability for our intended assays. All subjects will be interviewed using a structured questionnaire and will be asked to provide biological samples including blood and urine. Environmental risk factors (including lifestyle, habits, and diet) will be assessed through questionnaires.