Surgical treatment of multiple primary lung cancers.

Multiple primary lung cancers are now being recognized more frequently. Out of 1004 patients with a resected lung cancer, 32 (3.2%) presented a second primary and two of them a third primary lung cancer. A synchronous (S) primary was present in 7 and a metachronous (M) primary was present in 25. The histology was different in 1/7 with a S. and in 6/25 with a M. cancer. In all cases the cancer was located in another segment, lobe or lung. Out of the 7 with a S. cancer, 3 had a one stage and 4 a staged resection; out of the 25 with a M. cancer, 3 were treated by chemotherapy, 22 had a 2nd and 1 a 3rd operation to remove a new cancer. The mean time interval in M. cancer was 4 years, 8 months and was longer for adeno- (8 years) than for squamous cell carcinomas (4 years), longer for a contralateral cancer (6 years, 7 months) and longer for mild smokers (5 years, 1 month). The early mortality (10.3%) was 0/7 for S. and 3/22 for M. cancers. The three and five years actuarial survival of operated patients was 67% and 25% for S. and 43% and 31% for M. cancers. Survival is positively affected by a resection interval of more than 3 years and by 3 instead of 2 remaining lobes after the second resection. In conclusion a close follow-up of operated lung cancer patients is necessary and aggressive surgical approach is indicated for a new primary cancer.