Use of neostigmine to increase the rate of lung cancer detection by sputum cytology.

Neostigmine induction was investigated as a method for increasing the rate of detection of lung cancer in respiratory cytology samples. Eleven patients with dry and essentially nonproductive cough were given neostigmine, 15 mg by mouth or 0.5 mg by hypodermic injection. The quality of sputum produced was increased in all cases; the sputum was also more easily expectorated. Eight patients suspected of having lung cancer had previously negative cytologic examinations of sputum obtained by conventional methods. Following the administration of neostigmine, malignant cells indicating squamous-cell carcinoma were found in the sputum samples of three of these patients while dysplastic cells were detected in the samples from two patients. It is postulated that neostigmine intake may increase the excretion of mucous glands in the bronchial submucosa as well as the bronchial epithelium itself.