Tumor cell type versus staging in the prognosis of carcinoma of the lung.

From this and other studies, it is clear that the determination of tumor cell type is dependent on cellular and architectural patterns which are fraught with considerable interobserver and even intraobserver variations. Even though determination of cell type is semiobjective at best, previous reports have sought to determine prognosis solely on the basis of cell type or subtype while other studies have made attempts to define the prognosis of the disease based on even less precise terms. In seeking an answer to the question of which is more important for prognosis of lung cancer, cell type or TNM stage, the findings reported herein support the hypothesis that the TNM stage is the single most important factor for survival. This conclusion is substantiated by the following observations: 1. When cell type is stratified by stage, no significant differences can be determined in survival according to tumor cell type. 2. There is a minor difference (not statistically significant) in survival for tumor cell type when considering resected stage I tumors (67 of 99) in terms of adenocarcinomas which had a survival of 38 percent at 5 years versus squamous cell carcinomas which had a survival of 23 percent at 5 years. The numbers of cases in this study were not sufficiently large to comment on the possible difference between surgically resected large cell and small cell carcinomas. 3. TNM staging is a highly significant predictor in the survival of patients with lung cancer. The significance for survival by stage remains even if the data are stratified by the cell type diagnosis. These conclusions apply to the total group of 124 patients, and also to the subgroup of 99 surgically resected patients. Many reports have attempted to determine survival of carcinoma of the lung in terms of cell type without regard to its stage. Consequently, comparison of data from various institutions is difficult. We believe TNM staging of the disease not only allows reasonable comparison of data obtained from different institutions, but also, affords a useful and accurate means of assessing the extent of the disease and its prognosis.