Staging of esophageal cancer: TNM and beyond

Previous staging of esophageal cancer was based on a simple, orderly arrangement of increasing anatomic T, then N, then M classifications. This system is consistent with neither data nor cancer biology. Recent worldwide collaboration has provided data for unique, modern machine-learning analysis that has resulted in a new, data-driven staging system for cancer of the esophagus and esophagogastric junction. This new system is presented in the seventh editions of the AJCC and UICC Cancer Staging Manuals. It is more representative of and consistent with the clinical reality of survival of patients with esophageal cancer. Changes address problems of empiric stage grouping and lack of harmonization with stomach cancer. In addition, for the first time, nonanatomic cancer characteristics such as tumor location, histologic grade, and histopathologic cell type are incorporated. The new era of data-driven staging of esophageal cancer promises a bright future for staging of all cancers. However, more extensive worldwide collaboration is required to refine and broaden TNM classifications and identify cancer and patient characteristics that influence esophageal cancer stage and impact survival.