Abstract
Participants who were 50 years of age or older and with a cigarette index of 600 or more were screened annually by both sputum cytology and chest X-ray for the early detection of lung cancer in the Miyagi Program. From 1982 to 1992, 119, 240 examinations were made. Sputum specimens showed moderately atypical squamous cells (sputum diagnosis "C") in 465 cases (0.39%), suspicious cells or borderline atypical cells (sputum diagnosis "D") in 301 cases (0.25%), and cancer cells (sputum diagnosis "E") in 287 cases (0.24%). In the "E" cases, sputum specimens showed malignant cells with low grade atypia in 159 cases (sputum diagnosis "E1") and frankly malignant cells in 128 cases (sputum diagnosis "E2"). Among 588 cases with sputum diagnosis D or E, there were 229 cases (38.9%) of primary lung cancer, and 34 cases (5.8%) of upper respiratory tract cancer, 3 cases (0.2%) of metastatic lung cancer and 42 cases (7.1%) of dysplasia (borderline lesion) which were confirmed by bronchoscopic examination, especially selective brushing of all bronchial branches. Upper respiratory tract cancers were located in the larynx, pharynx, oral cavity, maxillary sinus and nasal cavity. Of the 229 primary lung cancers, 208 (90.8%) were squamous cell carcinoma, 14 (6.1%) adenocarcinoma, 4 large cell carcinoma, 2 small cell carcinoma and one was other cell type cancer. Among the 208 squamous cell carcinoma cases, 156 carcinomas (75%) were roentgenographically occult. It is often difficult to localize carcinomas by bronchoscopy and a thorough investigation is necessary. We must carefully follow up the cases with sputum diagnosis D or E, but in which localization is not confirmed.
