Abstract
Cytologic examination of sputum was performed in 161 of 252 cases of squamous cell carcinoma of the lung that were subsequently resected. Cytologically, 123 of these 161 patients were diagnosed as positive. When the tumor size was divided into two groups, either 3.0 cm or less or more than 3.1 cm in diameter, the diagnostic accuracy of sputum cytology showed no significant difference between these two groups. In all cases of squamous cell carcinoma, when invasion extended to proximally 0-II order bronchi, HI or N order of bronchus, and V or more distal bronchi, the diagnostic accuracy of sputum cytology was 83.3%, 75.0% and 63.0% respectively. There was significant difference between the accuracy levels of 83.3% and of 63.0%. In cases with tumors 3.0 cm or less in diameter, when tumor invasion extended proximally to 0-11 order of bronchi, the diagnostic accuracy of sputum cytology was 88.8%. With tumors in which the most proximal invasion of tumor was in 111 or IV order bronchi, the diagnostic accuracy was 66.6%. The diagnostic accuracy of sputum cytology in these two groups showed a significant difference.
In 30 cases of early stage squamous cell carcinoma in which sputum cytology was performed, the diagnostic accuracy in cases of tumors located in 0-II order bronchi was 100% whereas that of tumors located in DI or N order bronchi was only 58.3%. This shows that sputum cytology can be most useful for the detection of central type squamous cell carcinoma even at a very early stages. In peripheral type squamous cell carcinoma, in cases in which the tumor arose in III or IV order bronchi, it can be detected by sputum cytology even when roentgenologically occult.
