In patients undergoing lung resection for non-small cell lung cancer, is lymph node dissection or sampling superior?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'In patients undergoing lung resection for non-small cell lung cancer, is lymph node dissection or sampling superior?' Altogether 845 papers were found using the reported search, of which 14 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that in stage I tumours there is little difference in survival when performing either mediastinal lymph node dissection (MLND) or lymph node sampling. However, survival is increased when performing MLND in stage II to IIIa tumours. Increased accuracy in staging is not observed with MLND. However, MLND reliably identifies more positive N2 nodes which may offer advantages in postoperative adjuvant treatment in more advanced disease.