Gastroesophageal cancer: focus on epidemiology, classification, and staging

Gastroesophageal cancer (GEC), comprising proximal esophagogastric junction (EGJ) and distal gastric cancer (GC), is a significant public health concern. The epidemiology of these tumors has significantly changed over the past several decades especially in developed countries. There is a recognized decrease in incidence and mortality of distal GC and an increase in incidence and mortality of proximal EGJ cancer. The changing epidemiology is thought to be mainly due to changing trends of risk factors such as lower incidence of Helicobacter pylori infection and increasing incidence of obesity and gastroesophageal reflux. Histologically, EGJ cancers are adenocarcinoma (AC), while distal esophagus may be squamous cell carcinoma (SCC) or AC. Distal GC is predominantly AC. Following anatomical and histological distinction, tumors are staged with endoscopic ultrasound (EUS), computerized tomography (CT), and often positron emission tomography (PET) with or without diagnostic laparoscopic and peritoneal washing. Accurate staging of tumors, with emphasis on excluding occult metastasis, is imperative to avoid unnecessary surgical resection. Therefore, it is crucial to understand how these tumors are classified, the associated epidemiology, and the current standards of staging prior to selecting the appropriate course of therapy. In this review we will discuss the epidemiology, classification, and staging of locally advanced GEC.