Prognostic significance of the number of removed lymph nodes at lobectomy in patients with positron emission tomography-computed tomography-negative N2 non-small cell lung cancer.

Background: We assessed the relation between the extent of lymph node (LN) dissection and the prognosis for positron emission tomography-computed tomography (PET-CT)-negative patients with clinical early-stage non-small cell lung cancer (NSCLC), undergoing lobectomy and mediastinal LN dissection.

Methods: 277 patients with clinical stage I/II NSCLC who had undergone a preoperative PET-CT scan followed by lobectomy were analysed retrospectively. The prognostic value of age, maximum standardized uptake value (SUVmax) of the tumour, tumour size, carcinoembryonic antigen and number of dissected LNs was assessed to determine any association with overall survival and disease-free survival.

Results: 31 patients developed postoperative relapse, and multiple logistic regression revealed that the number of dissected LNs was an independent factor predicting relapse. Patients were categorized into groups according to the number of LNs dissected (group I, < 10; group II, ≥ 10). There were no statistical differences between 2 groups but group II patients had a lower relapse rate (6.3%, p = 0.003) and better disease-free survival (74.95 months, p = 0.045).

Conclusions: Mediastinal LN dissection is still important for clinical early-stage NSCLC patients undergoing lobectomy even when the preoperative PET-CT is negative, and results in fewer relapses and improved disease-free survival.