Prognostic significance of 4R lymph node dissection in patients with right primary non-small cell lung cancer

Background To investigate the prognostic significance of station 4R lymph node (LN) dissection in patients who underwent operations for right primary non-small cell lung cancer (NSCLC). Methods We performed a retrospective study involving patients with right primary NSCLC who received lobotomy or pneumonectomy with mediastinal LN dissection between January 2011 and December 2017. Propensity score matching was performed. Disease-free survival (DFS) and overall survival (OS) were compared between patients with and without station 4R dissection. Results Our study included 2070 patients, with 207 patients having no station 4R dissection (S4RD− group) and 1863 patients having station 4R dissection (S4RD+ group). The 4R LN metastasis rate was 13.4% (142/1748), higher than that for other mediastinal LN metastases. Compared with the S4RD− group, the S4RD+ group had higher 5-year DFS (48.1% vs. 39.1%, P = 0.009) and OS (54.4% vs. 42.8%, P = 0.025). Station 4R dissection was an independent risk factor for DFS (odds ratio, OR, 1.28, 95% confidence interval, CI, 1.08–1.64, P = 0.007) and OS (OR 1.31, 95% CI 1.04–1.63, P = 0.018). Patients with adjuvant chemotherapy had a better prognosis after station 4R dissection than those without adjuvant chemotherapy (57.4% vs. 52.3%, P = 0.006). The 5-year OS in the station 4R metastasis group was lower than that in the station 4R non-metastasis group (26.9% vs. 44.3%, P = 0.006) among N2 patients. The 5-year OS of the single-station 4R metastasis group was lower than that of the single-station 7 metastasis group (15.7% vs. 51.6%, P = 0.002). Conclusions Station 4R metastasis was the highest among all the mediastinal station metastases in right primary NSCLC patients. Station 4R dissection can improve the prognosis and should be recommended as a routine procedure for these patients.