Can lobe-specific lymph node dissection be an alternative to systematic lymph node dissection in treating early-stage non-small cell lung cancer: a comprehensive systematic review and meta-analysis?

Background: Whether lobe-specific lymph node dissection (L-SLND) could serve as an alternative to systematic lymph node dissection (SLND) in treating early-stage non-small cell lung cancer (NSCLC) remains unclear. Therefore, we conducted this comprehensive meta-analysis to compare the effect of L-SLND with that of SLND in treating early-stage NSCLC. Methods: A systematic literature search in PubMed and Embase was conducted to identify relevant studies up to 30 November 2017. Data including 5-year overall survival (OS) and disease-free survival (DFS) rates, recurrence rates, and morbidity rate were extracted and analysed. Results: A total of six studies [one randomized controlled trial (RCT) and five retrospective cohort studies] consisting of 2,037 patients with early-stage NSCLC were included for analysis. Meta-analysis showed that there was no significant difference of 5-year OS [81.7% and 79.5%, respectively; risk ratio (RR)=1.021; 95% confidence interval (CI), 0.977-1.068; P=0.352] and DFS (76.4% and 69.9%, respectively; RR=1.061; 95% CI, 0.999-1.128; P=0.054) between patients treated with L-SLND and those with SLND. Moreover, there was also no significant difference of total recurrence rates (24.3% and 25.8%, respectively; RR=0.892; 95% CI, 0.759-1.048; P=0.166) and loco-regional recurrence rates (7.9% and 9.3%, respectively; RR=0.851; 95% CI, 0.623-1.162; P=0.310) between patients treated with L-SLND and those with SLND. However, patients treated with L-SLND yielded a significant lower morbidity rate than those treated with SLND (10.2% and 13.5%, respectively; RR=0.681; 95% CI,=0.521-0.888; P=0.005). Conclusions: L-SLND yielded a significantly lower risk of morbidity compared to SLND without compromising long-term oncologic outcomes based on available studies with relatively poor quality. L-SLND may serve as an alternative to SLND in treating early-stage NSCLC. Further well-conducted RCTs, however, are badly needed to confirm and update our conclusions.