Yasuhiro Tsutani

Several clinical trials have been revolutionizing the perioperative treatment of early-stage non-small cell lung cancer (NSCLC). Many of these clinical trials involve cancer immunotherapies with antibody drugs that block the inhibitory immune checkpoints programmed death 1 (PD-1) and its ligand PD-L1. While these new treatments are expected to improve the treatment outcome of NSCLC patients after pulmonary resection, several major clinical questions remain, including the appropriate timing of immunotherapy (neoadjuvant, adjuvant, or both) and the identification of patients who should be treated with neoadjuvant and/or adjuvant immunotherapies, because some early-stage NSCLC patients are cured by surgical resection alone. In addition, immunotherapy may induce immune-related adverse events that will require permanent treatment in some patients. Based on this fact as well, it is desirable to select appropriate patients for neoadjuvant/adjuvant immunotherapies. So far, data from several important trials have been published, with findings demonstrating the efficacy of adjuvant atezolizumab (IMpower010 trial), neoadjuvant nivolumab plus platinum-doublet chemotherapy (CheckMate816 trial), and several perioperative (neoadjuvant plus adjuvant) immunotherapies (AEGEAN, KEYNOTE-671, NADIM II, and Neotorch trials). In addition to these key trials, numerous clinical trials have reported a wealth of data, although most of the above clinical questions have not been completely answered yet. Because there are so many ongoing clinical trials in this field, a comprehensive understanding of the results and/or contents of these trials is necessary to explore answers to the clinical questions above as well as to plan a new clinical trial. In this review, we comprehensively summarize the recent data obtained from clinical trials addressing such questions.

Objectives Selective mediastinal lymph node dissection based on lobe-specific metastases is widely recognized in daily practice. However, the significance of mediastinal lymph node dissection for N1-positive tumors has not been elucidated. Methods We retrospectively reviewed 359 patients with N1-positive lung cancer who underwent lobectomy with systematic mediastinal lymph node dissection (systematic lymph node dissection) (n = 150) and lobe-specific mediastinal lymph node dissection (lobe-specific lymph node dissection) (n = 209). The operative and postoperative results and their propensity score-matched pairs were compared. The factors affecting survival were assessed using competing risk and multivariable analyses. Results The cumulative incidence of recurrence and the cumulative incidence of cancer-specific death were not significantly different between systematic and lobe-specific lymph node dissection in entire cohort. In the propensity score-matched cohort (83 pairs), systematic lymph node dissection tended to detect N2 lymph node metastasis more frequently (55.4 vs. 41%, P = 0.087). Eleven patients (13.2%) in the systematic lymph node dissection group had a metastatic N2 lymph node ‘in the systematic lymph node dissection field’ that lobe-specific lymph node dissection did not dissect. The oncological outcomes between patients undergoing systematic lymph node dissection (5-year cumulative incidence of recurrence, 62.1%; 5-year cumulative incidence of cancer-specific death, 27.9%) and lobe-specific lymph node dissection (5-year cumulative incidence of recurrence, 60.1%; 5-year cumulative incidence of cancer-specific death, 23.3%) were similar. The propensity score-adjusted multivariable analysis for cumulative incidence of recurrence revealed that the prognosis associated with systematic lymph node dissection was comparable with the prognosis with lobe-specific lymph node dissection (hazard ratio, 1.17; 95% confidence interval, 0.82–1.67; P = 0.37). Conclusions The extent of lymph node dissection can affect accurate pathological staging; however, it was not associated with survival outcome in the treatment of N1-positive lung cancer.