Endoscopic criteria of early squamous cell carcinoma of the bronchus

Background. Early lung cancer, not extending beyond the bronchial cartilaginous layer without regional lymph node involvement is considered curable by endoscopic laser therapy or limited surgery. The endoscopic criteria for early squamous cell carcinoma of the bronchus, however, have not yet been determined. Methods. For 44 resected lesions of roentgenographically occult bronchogenic squamous cell carcinomas, the relationship between endoscopic findings and the degree of histologic extent of tumor was examined. Results. The lesions were divided into three types: polypoid or nodular (PN), flatly spreading (FS), and mixed. Thirty‐three lesions arising from the central bronchus included 7, 19, and 7 of the PN, FS, and mixed types, respectively. In the central lesions, the degree of transmural invasion and the greatest dimension correlated, but the degree of intramural invasion of PN‐type lesions was higher than that of the FS type. The PN‐type lesions smaller than 10 mm and the FS type smaller than 15 mm in greatest dimension were found within the cartilaginous layer without regional lymph node involvement. All lesions of the mixed type were larger than 20 mm. Three of the lesions larger than 20 mm had regional lymph node involvement. All 11 lesions originating in the peripheral bronchus were of the FS type, and a lesion of only 5 mm in greatest dimension had extracartilaginous invasion. Conclusions. The endoscopic criteria of early squamous cell carcinoma of the bronchus may be applied to central PN lesions smaller than 10 mm and central FS lesions less than 15 mm in greatest dimension. Any lesions of mixed type should be excluded from the criteria.