Lymph Node Examination for Stage I Second Primary Lung Cancer Patients Who Received Second Surgical Treatment

Purpose This study aims to investigate the effect of lymph node examination on overall survival (OS) and lung cancer-specific survival (LCSS) in stage I second primary lung cancer (SPLC) patients who underwent second pulmonary resection. Patients and Methods We conducted a retrospective study with the Surveillance, Epidemiology, and End Results (SEER) database to identify stage I SPLC patients who received surgery from 1998 to 2015. The Kaplan–Meier method with landmark analysis and multivariable Cox regression analysis were performed to evaluate the prognostic value of lymph node examination. Results A total of 842 patients from the SEER database with stage I SPLC who underwent a second surgical treatment were included. The 5-year survival rate was 54.8% for the whole cohort. Multivariable analysis revealed that the number of lymph nodes examined (LNE) was associated with better OS and LCSS in SPLC patients after 12 months postoperatively. Patients with contralateral SPLC had significantly more nodes removed than those with ipsilateral SPLC. For contralateral SPLC, more than 10 LNE was correlated with improved long-term survival outcomes. Ipsilateral SPLC patients benefited from 4 or more LNE. However, the current analysis did not show a significant survival benefit from lymph node examination within 12 months after surgery. Conclusions For stage I SPLC patients who received surgical treatment after initial resection, an adequate number of LNE would improve both OS and LCSS. We recommend more than 10 LNE for contralateral SPLC and at least 4 LNE for ipsilateral SPLC.