Surgery For Metachronous Second Primary Lung Cancer Versus Surgery For Primary Lung Cancer: A Propensity Score-Matched Comparison Of Postoperative Complications And Survival Outcomes

OBJECTIVES: Surgical treatments for metachronous second primary lung cancer (MSPLC) may be increasing. It was thought that surgery for MSPLC is associated with high mortality and morbidity. However, recent diffusion of minimally invasive surgical procedures may improve the safety of surgery for MSPLC. The aim of this study was to clarify the safety and prognosis of surgery for MSPLC compared with that for primary lung cancer (PLC).METHODS: We reviewed medical records of 1340 patients who underwent pulmonary resection for non-small-cell lung cancer between 2006 and 2013. We identified patients with PLC and those with MSPLC, and surgical parameters and survival outcome were compared. To eliminate selection bias between the MSPLC group and the PLC group, propensity score-matched analysis on the basis of clinicopathological factors was performed.RESULTS: Fifty-three patients underwent resection for MSPLC. Propensity score matching identified 50 patients from each treatment group. Of the 50 MSPLC patients, 41 (82.0%) underwent segmentectomy or wedge resection, 44 (82.0%) had clinical Stage I tumour and 36 (72.0%) received resection via video-assisted thoracoscopic surgery approach. Postoperative complications with a severity of Grade II or more occurred in 11 (22.0%) patients. The incidence of postoperative complications in the MSPLC group was not different from that of the PLC group (P = 0.4894). The 5-year overall survival rates were 68.7% and 83.0% in the PLC and the MSPLC groups, respectively. There was no significant difference between the PLC and the MSPLC groups in terms of overall survival (P = 0.2018, log-rank test).CONCLUSIONS: Pulmonary resection for MSPLC was safely performed with low short-term morbidity similar to that of PLC, and its longterm overall survival was acceptable.