Significantly favourable outcome for patients with non-small-cell lung cancer stage IIIA/IIIB and single-station persistent N2 (skip or additionally N1) disease after multimodality treatment.

Objectives Persistent lymph nodes infiltration after neoadjuvant treatment remains a controversial topic in the treatment of stage III non-small-cell lung cancer (NSCLC). The aim of this study is to identify subgroups with persistent N2 disease, who could experience survival benefit from the addition of surgery. Methods A retrospective mono-institutional study was conducted to analyse all patients with a final histopathology of NSCLC and persistent mediastinal disease after induction chemotherapy or chemoradiotherapy and surgery from January 1998 to June 2015. Results A total of 145 patients (93 men, 52 women) fulfilled the inclusion criteria. The median age was 60 years (range 38-78). A total of 82 (56.5%) patients received a lobectomy, 48 (33.1%) a pneumonectomy, 11 (7.6%) a bilobectomy and 4 (2.6%) an anatomical segmentectomy; 128 (88.3%) were completely resected (R0). Operative mortality was 2.6% (4 patients), and morbidity was 35.2% (51 patients). Overall survival at 5 years was 47.3% (n = 19) for single N2 (skip), 30.2% (n = 16) for single N2 and N1 lymph nodes and under 5% (n = 1) for multiple mediastinal stations disease. Overall survival at 5 years after lobectomy/bilobectomy was not statistically different than after pneumonectomy (33.5% vs 20.5%, P = 0.082). Disease-free survival at 5 years was 30.6% (n = 6) for ypN2a1, 23.4% (n = 7) for ypN2a2 and under 5% (n = 1) for ypN2b status. Conclusions Lobectomy or bilobectomy has to be taken into account as a potentially curative option with promising long-term results for patients after induction treatment and persistent single-station N2 involvement (skip or additionally N1 status). Trial registry number 14-6138-BO.