Resected synchronous primary malignant lung tumors: A population-based study

Background. Synchronous lung tumors with a histology indicating primary lung carcinomas detected preoperatively or at surgery may represent intrapulmonary metastases from a primary tumor or two or more simultaneously occurring primary tumors. The situation is rare. This study was conducted to assess the characteristics and outcome for this patient group. Methods. All clinical and pathology departments in Norway submit standardized reports on cancer patients to the Cancer Registry of Norway. The registry also has a law-regulated authority to collect supplemental information on diagnosis, treatment, and outcome for all cancer patients from hospitals. During the period 1993 to 2000, lung cancer was diagnosed in 15,308 patients, of whom 2528 underwent resection in 24 hospitals. This investigation included all patients with histology demonstrating primary lung carcinoma in more than one tumor in the resected specimen. Results. Synchronous malignant tumors were found in 94 patients: 66 had two tumors and the remaining 28 had three or more. The tumors were of similar histology in 85 cases. The tumors were diagnosed preoperatively in 11 patients and peroperatively or in the resected specimen in the other 83. The 5-year relative survival rate was 31.4% for patients with squamous cell carcinomas, 23.2% for adenocarcinomas, and 42.7% for patients with tumors of other histology ( two carcinoids). Conclusions. Survival in patients with synchronous lung tumors is good compared with historical reports on patients with distant metastases or other variants of T4 tumors; thus, they should be considered for surgery.