Cytologic studies of sputum and bronchial secretions in primary carcinoma of the lung.

Since most primary carcinomas of the lung are bronchogenic they tend to exfoliate cells into the bronchial lumen. The normal current of the bronchial secretions acts as a constant natural' "curettage" carrying these cells upward in the sputum. It has been demonstrated1 that neoplastic cells can be recognized in the sputum, after suitable preparation, in over 80 per cent of cases of proved carcinoma of the lung. The diagnostic accuracy can be appreciated when this percentage is contrasted with that achieved with other single procedures. The cytologic study of sputum for neoplastic cells is rapidly being accepted as a valuable aid in the diagnosis of cancer of the lung. The prerequisites to the effective use of this type of study are two: adequate cytologic technics and an extensive knowledge of the cellular components of sputum.