Prognostic indicators for survival in stage I carcinoma of the lung: a histologic study of 47 surgically resected cases

In a previous study of 91 consecutive lung cancer cases, we reported that tumor stage was the only significant predictor of survival, with all 5-yr survivors having Stage I disease. Approximately half of the 47 Stage I cases survived 5 yr, so the present study was initiated to determine which histologic features were predictive of survival for Stage I cases. An average of 10 slides per case was evaluated independently by three pathologists, and each slide was subjectively scored using previously agreed criteria for the following parameters: vascular or lymphatic invasion; anaplasia; mitotic rate; inflammatory host response; and the presence or absence of necrosis, tumor giant cells, a central scar, mucin production, benign giant cell reaction, or desmoplasia. Survival was also correlated with patient's age, sex, tumor (T) and nodal (N) status, tumor cell type, and histologic heterogeneity. All three observers found the extent of tumor necrosis to be a significant negative predictor of survival (P less than 0.05). One observer found tumor giant cells to be an adverse factor, another observer found scar carcinomas to have worse survival, and a third observer found lymphocytic inflammatory host response to be a positive predictor and venous invasion to be a negative predictor of survival (P less than 0.05). All other parameters showed no significant correlation with survival. The finding of some parameters which correlated with survival according to one but not the other two observers indicates that the results of studies of histologic prognostic indicators by a single observer may not be valid for other pathologists attempting to use the same subjective criteria.