Abstract
Ffity-five patients suffering from second primary lung carcinoma, 10 synchronous and 45 after resection for lung carcinoma (metachronous), have been observed from 1400 resections. The first manifestation of a second carcinoma in this series has always been the appearance of a new shadow in the follow-up radiograph. In our experience, second primary lung carcinoma is a disease affecting only heavy cigarette smokers. Heavy cigarette smokers suffering from squamous-cell carcinoma are at special risk. The results of re-operation, the significance of the time interval between the original operation and the appearance of the second primary carcinoma, and the slow growth rate of some second primaries are briefly discussed. No clear-cut methods exist for distinguishing a second primary from a metastasis from the original carcinoma.