[JCOG lung cancer surgery trial series: review and interpretation]

Surgery is so far the most effective treatment for early-stage non-small cell lung cancer (NSCLC). Since the 1990s, the pathology spectrum of early-stage lung cancer has gradually changed because of the increased detection of ground-glass opacity (GGO). The findings from preoperative thin-section computed tomography are strong predictors for the invasiveness and lymph node involvement of GGO, and limited surgery is believed to be implemented safely for radiological less invasive lesions, which calls into question the dominance of lobectomy. After the JCOG0201 trial establishing the radiologic criteria of pathological noninvasiveness for lung adenocarcinoma, the Japan Clinical Oncology Group (JCOG) and the West Japan Oncology Group (WJOG) have successively carried out a series of prospective imaging-guided trials to investigate the optimal surgical procedure for early-stage lung cancer. JCOG0804, was a single-arm, non-randomized, confirmatory trial to evaluate the efficacy and safety of sublobar resection (wedge resection and segmentectomy) for GGO dominant peripheral lung cancer. The primary end point was 5-year relapse-free survival. JCOG0802/WJOG4607L, was a multicentre, open-label, phase 3, randomized, controlled, non-inferiority trial to investigate if segmentectomy was non-inferior to lobectomy in patients with small-sized peripheral NSCLC. The primary endpoint was 5-year overall survival. JCOG1211 was also a non-randomized confirmatory trial to confirm the efficacy of a segmentectomy for clinical T1N0 lung cancer with dominant GGO. The primary endpoint was 5-year relapse-free survival. The findings of JCOG0804 and JCOG0802, and the primary analysis results of JCOG1211 have been officially published. This article systematically reviewed and interpreted the results of the JCOG lung cancer surgery trial series.