Classification and Staging for Junctional Cancer

Abstract

Classification and staging for adenocarcinomas (ADC) around the gastroesophageal junction (GEJ) are controversial. The rising incidence of Barrett’s cancer, and the migration of tumor from being a predominantly distal gastric location to the proximal stomach in the past 30 years have stimulated much interest in the study of these cancers. The Siewert classification separates ADC in an area 5 cm proximal and distal to the GEJ into three types: Type I includes ADC of the lower esophagus predominantly Barrett’s esophagus in origin, type II comprises of ADC centering on the GEJ, and type III can be regarded as proximal stomach cancer which has infiltrated into the GEJ. This is a purely anatomical classification. While it can be shown that the three types of tumors have fairly distinct clinico-pathological characteristics, such as gender ratios, proportion of intestinal versus diffuse types and so on, whether the classification is of sufficient value in pre-treatment planning is controversial. Staging for GEJ tumors is even more problematic; it has been uncertain whether one should stage these tumors according to the esophageal or gastric system. For the first time, the latest AJCC / UICC system groups these tumors under esophageal cancer, rather than gastric cancer, as long as the anatomical GEJ is involved. Some concordance has emerged, such as the N-staging has become uniform for both esophageal and gastric tumors. This latest staging was also generated by actual data from a World Wide Esophageal Collaboration (WECC). While this is definitely a right direction to take, it remains a controversial area. Data is emerging showing the accuracy and use of the staging system, but modifications are no doubt necessary in the future.