[Treatment of double primary lung cancers in 23 patients]

Twenty-three patients with double primary lung cancers (10 synchronous, 13 metachronous) were diagnosed from 1967-1988 by operation, pathology or cytology. The incidence of double primary lung cancers was 1.5% (23/1527) among all lung cancers patients admitted during the same interval. Ten of these 23 patients (43.2%) received operative treatment. The synchronous double primaries were treated by limited resection. For the metachronous lesions, the first lung cancer was treated by the standard lobectomy and the second lesion by wedgectomy. The average survival time for the synchronous double lung cancers was 13 months which was similar to that of radiochemotherapy. For the metachronous cancers, the 5-year survival of 5 operated patients was 40%. Only one of the other 8 patients as treated by non-operative means survived for more than 3 years. This shows the superiority of surgery to the non-operative treatment. Pathologic classification of the lesions in this series showed that 10 (43%) had identical types with the majority (6 patients) being of squamous-squamous cell type. In the 13 patients (57%) with different pathologic types 7 were of squamous-adenocarcinomas. Diagnostic criteria, operative method and vigilance to the possibility of double primary lung cancers are also discussed.