Sputum cytology by the Saccomanno method in diagnosing lung malignancy.

From 1,488 patients, satisfactory sputum was available for cytologic diagnosis. Overall diagnoses were correct in 85.4% of patients, false negative in 193 patients (13.0%), and false positive in 24 patients (1.6%). In patients with a malignant lung process, cytologic diagnoses were correct in 228 patients (54.2%) and false negative in 193 patients (45.8%). In patients with primary lung cancer, the proportion of correct positive diagnoses increased from 0.47 to 0.87 with one to five sputum specimens examined. In patients with metastatic disease, the figures were 0.35 with one specimen examined and 0.38 with two and more sputum specimens. Cytologic typing accuracy was 67% for large-cell carcinomas, 73% for adenocarcinomas, 91% for small-cell lung cancers, and 98% for squamous-cell carcinomas. For the clinically most relevant groups of nonsmall-cell lung cancer and small-cell lung cancer, these figures were 99% and 91%, respectively.