Multiple primary lung carcinomas: prognosis and treatment.

From 1955 to 1990, 111 patients have been treated for multiple primary lung carcinomas. Criteria for diagnosis were: (1) different histology (n = 44); or (2) same histology, but disease-free interval at least 2 years (n = 39), origin from carcinoma in situ (n = 19), or metachronous disease in different lobe (n = 9) with no cancer in common lymphatics or extrapulmonary metastasis at the time of diagnosis. The second cancer was synchronous in 33 patients (30%) and metachronous in 78 (70%). Metachronous disease developed at a median interval of 48 months. Five-year survival for patients with metachronous and synchronous disease from the time of initial diagnosis of cancer was 70% and 44%, and 10-year survival was 42% and 23%, respectively. Survival after the development of a metachronous lesion was 23% at 5 years. Survival from the time of initial diagnosis was significantly better for metachronous versus synchronous, late (24 month disease-free interval) versus early metachronous disease, and adenocarcinoma versus epidermoid carcinoma. The first cancer was completely resected in 103 patients (93%), but complete resection of a metachronous tumor was possible in only 54 patients (69%). Complete resection of second primary cancers resulted in significantly (p less than 0.0001) prolonged 5-year survival compared with incomplete resection (38% versus 9%). Excluding patients requiring pneumonectomy, initial resection limited subsequent resection in only 7 patients (9%) with metachronous disease. We conclude that patients surviving treatment of primary lung cancers require lifelong screening for multiple primary lung carcinoma, and complete resection is recommended whenever possible.