Cancer of the lung. Histology and biological behavior.

Abstract

A clinicopathologic survey has been made of 666 cases of lung cancer in whom histological confirmation of the diagnosis was possible by the study of surgical material. A simple histological classification into squamous celled tumors, well and poorly differentiated; adenocarcinomas, well and poorly differentiated; and undifferentiated tumors is used. The histological type of tumor is related to the site in the bronchial tree at which it develops. The authors suggest that squamous cell carcinomas are more often central in origin because of the centripetal distribution of squamous metaplasia and that, because of their site, they are less likely to be operable and more likely to show the symptoms cough and hemoptysis. The authors confirm an association with cigarette smoking but report no differential association with squamous cell carcinoma. They draw attention to the fact that smoking is a contributory cause of lung cancer rather than a necessary cause and that in any individual case the development of a tumor depends on a series of interacting events. Resectability, and hence prognosis, in lung cancer is dependent primarily on the site of the lesion and secondarily on the degree of differentiation. The authors urge that information on the endoscopic findings be included in reports on the outcome of lung cancer treatment. The course of the disease, shown by the length of survival of patients both with and without operation, is significantly more rapid in those patients whose tumors are undifferentiated than in those whose lesions show squamous or glandular differentiation.