8th edition AJCC/UICC staging of cancers of the esophagus and esophagogastric junction: application to clinical practice
The 8th edition of the American Joint Committee on Cancer (AJCC) staging of epithelial cancers of the esophagus and esophagogastric junction (EGJ) presents separate classifications for clinical (cTNM), pathologic (pTNM), and postneoadjuvant (ypTNM) stage groups. Histopathologic cell type markedly affects survival of clinically and pathologically staged patients, requiring separate groupings for each cell type, but ypTNM groupings are identical for both cell types. Clinical categories, typically obtained by imaging with minimal histologic information, are limited by resolution of each method. Strengths and shortcomings of clinical staging methods should be recognized. Complementary cytology or histopathology findings may augment imaging and aid initial treatment decision-making. However, prognostication using clinical stage groups remains coarse and inaccurate compared with pTNM. Pathologic staging is losing its relevance for advanced-stage cancer as neoadjuvant therapy replaces esophagectomy alone. However, it remains relevant for early-stage cancers and as a staging and survival reference point. Although pathologic stage could facilitate decision-making, its use to direct postoperative adjuvant therapy awaits more effective treatment. Prognostication using pathologic stage groups is the most refined of all classifications. Postneoadjuvant staging (ypTNM) is introduced by the AJCC but not adopted by the Union for International Cancer Control (UICC). Drivers of this addition include absence of equivalent pathologic (pTNM) categories for categories peculiar to the postneoadjuvant state (ypT0N0-3M0 and ypTisN0-3M0), dissimilar stage group compositions, and markedly different survival profiles. Thus, prognostication is specific for patients undergoing neoadjuvant therapy. The role of ypTNM classification in additional treatment decision-making is currently limited. Precision cancer care advances are necessary for this information to be clinically useful.