Refining esophageal cancer staging

Abstract

Objective: Cancer staging is dynamic, reflecting accrual of knowledge and experience in treatment. The objectives of this study were to assess current esophageal cancer staging and to determine whether refinements of classification and stage grouping are necessary. Methods: From 1983 through November 2000, 480 patients underwent esophagectomy without induction therapy. Depth of tumor invasion (T), regional lymph node status (N), distant status (M), number of metastatic regional lymph nodes, and histopathologic type and grade were subjected to survival-tree analysis, multivariable Cox and hazard function analysis, and residual misclassification risk analysis. Results: Inhomogenity of survival was found within and lack of distinction was found between current American Joint Committee on Cancer staging groups, supporting the need for refinement. T1 and N1 were redefined on the basis of survival differences. T1a is intramucosal cancer, T1b is submucosal cancer (P = .008), N1 is 1 or 2 metastatic regional lymph nodes, and N2 is 3 or more metastatic regional lymph nodes (P = .01). Current subclassification of M1 is not warranted (P = .9). Histopathologic type (P = .17) and grade (P = .3) minimally refined staging. Reassignment of staging groups constrained by American Joint Committee on Cancer definitions of stages 0 and IV produced less monotonic, distinctive, and homogeneous survival than free assignment of staging groups. Conclusions: Current American Joint Committee on Cancer staging of esophageal cancer is inadequate. Refinement requires redefinition of T1, N1, and M1 classifications. Stage grouping within the constraints of American Joint Committee on Cancer definitions produces less accurate prognosis than free assignment based on survival data.