The occurrence of a second lung tumor after surgical removal of lung cancer usually indicates a lung cancer metastasis, but sometimes a new lesion proves to be a new primary lung cancer, i.e., metachronous lung cancer. The goal of the present study was to conduct a clinical evaluation of patients with metachronous lung cancer and lung cancer metastasis, and to compare the early and distant outcomes of surgical treatment in both cancer types. There were 26 age-matched patients with lung cancer metastases and 23 patients with metachronous lung cancers, who underwent a second lung cancer resection. We evaluated the histological type of a resected cancer, the extent of thoracosurgery, the frequency of early postoperative complications, and the probability of 5-year survival after the second operation. The findings were that metachronous lung cancer was adenocarcinoma in 52% of patients, with a different histopathological pattern from that of the primary lung cancer in 74% of patients. In both cancer groups, mechanical resections were the most common surgery type (76% of all cases), with anatomical resections such as segmentectomy, lobectomy, or pneumectomy being much rarer conducted. The incidence of early postoperative complications in metachronous lung cancer and lung cancer metastasis (30% vs. 31%, respectively) and the probability of 5-year survival after resection of either cancer tumor (60.7% vs. 50.9%, respectively) were comparable. In conclusion, patients undergoing primary lung cancer surgery require a long-term follow-up due to the risk of metastatic or metachronous lung cancer. The likelihood of metachronous lung cancer and pulmonary lung cancer metastases, the incidence of postoperative complications, and the probability of 5-year survival after resection of metachronous lung cancer or lung cancer metastasis are similar.
Keywords: Histopathology; Lung cancer; Metachronous cancer; Metastasis; Non-small cell lung cancer; Survival; Thoracic surgery; Tumor.