Risk Factors for Adenocarcinoma and Squamous Cell Carcinoma of the Esophagus and Lung

Abstract

Introduction: The incidence of adenocarcinoma of the esophagus and lung has been rising in developed countries and surpassing the occurrence of its squamous cell counterpart. The only confirmed risk factor for esophageal adenocarcinoma is Barrett's esophagus, which is a consequence of gastroesophageal reflux disease (GERD). No risk factor has been found to be predictive of adenocarcinoma of the lung, even for non-smokers. Since the incidence of both these cancers is rising in the US along with a parallel increase in obesity and the metabolic syndrome, we investigated possible risk factors for these two types of cancer. Methods: We retrospectively reviewed the electronic medical records of all patients with a confirmed diagnosis of esophageal and lung cancer at one hospital between 1995 and 2015. The cohort was divided into four groups: 1.Esophageal adenocarcinoma, 2.Esophageal squamous cell carcinoma, 3.Lung adenocarcinoma, 4. Lung squamous cell carcinoma. Baseline demographic and clinical data were analyzed with the Mann-Whitney Test for continuous variables and the chi square test or Fisher's Exact Test for categorical variable.s Results: Compared to esophageal squamous cell carcinoma cases, esophageal adenocarcinoma patients were more likely to be white, non-smokers, non-alcoholics, have a higher BMI, diabetes mellitus (DM), hyperlipidemia, coronary artery disease, and GERD. They were also more likely to be taking proton pump inhibitors (PPI), statins and metformin. Esophageal squamous cell carcinoma patients were more likely to have chronic obstructive pulmonary disease (COPD). Compared to lung squamous cell carcinoma patients (n=124), lung adenocarcinoma patients (n=162) were more likely to be younger at the time of diagnosis, have a higher BMI, have GERD, COPD, and use PPI and metformin. The squamous cell cancer of the lung group was more likely to be current smokers. We then grouped the adenocarcinoma patients (esophagus and lung) and the squamous cell carcinoma patients (esophagus and lung) to examine risk factors. The adenocarcinoma group was younger and more likely to be white, have higher BMI, DM, hypertension, hyperlidemia, GERD, and more likely to be on PPI, statins, and metformin. The squamous cell group was more likely to have COPD and be current smokers.Table 1: Characteristics of patients with adenocarcinoma (esophagus and lung) and squamous cell carcinomaConclusion: Esophageal and lung adenocarcinoma groups share some common risk factors that include obesity and its associated metabolic syndrome (diabetes, hypertension, hyperlipidemia) and GERD.