Multiple primary lung cancers.

Seventy-five cases of multiple primary lung cancers, representing 3.78% of a series of 1980 consecutively resected tumors, were divided into 24 synchronous and 51 metachronous cancers, according to the criteria of Martini and Melamed. They all concerned tobacco-smoking men. The synchronous tumors were symptomatic in 66% of the cases, the metachronous tumors in 37%. Nine synchronous locations were unilateral and 15 were bilateral; 20 metachronous locations were ipsilateral and 31 were contralateral. There were three third metachronous cancers. The resection of both tumours was performed for 15 synchronous cancers and for 19 metachronous cancers, including two third metachronous tumors. There were two deaths related to metachronous cancers. No patient with resected synchronous cancers survived 5 years, while 20% of patients with resected metachronous cancers survived this period. Synchronous cancers appear to represent an advanced stage. Metachronous cancers are often diagnosed too late.