[Lung cancer: is surgery an option for persisting N2 after induction therapy?]

Induction chemotherapy followed by surgical resection has been a treatment option for stage IIIA3 N2 non-small cell lung cancer since publication of some small randomised trials during the 1990s. Later on other studies suggested a poor prognosis in cases of persistent N2 disease, so surgical treatment for these patients was not recommended. This study analyses the outcome of patients with persisting N2 disease and tries to identify prognostic parameters within that group of patients.

We conducted a retrospective cohort study with 50 patients after induction therapy for stage IIIA N2 NSCLC. We analysed the influence of the postoperative lymph node involvement as well as the number of involved lymph nodes on the overall survival.

50 patients with potentially resectable stage IIIA N2 were included in the analysis. In 25 cases (50 %) a persisting N2 remained after induction therapy with cisplatin/gemcitabine, 11 patients had a mediastinal downstaging. 14 patients did not qualify for surgery because of disease progression or comorbidities. The resection consisted in 29 cases of a lobectomy or bilobectomy; two times pneumonectomy was necessary and 4 segmentectomies and one atypical resection were performed. The median survival of patients with persisting N2 (ypN2) was 14.6 months, if mediastinal downstaging was achieved (ypN0/1) it was 22.3 months (p = 0.172). The number of involved mediastinal lymph nodes was a significant prognostic factor. If less than 6 lymph nodes were involved the mean survival was 17.5 months, while it was 8.6 months in patients with more than 6 involved lymph nodes (p < 0.01).

The median survival for patients with persisting N2 disease is less favourable compared to patients with mediastinal downstaging. However, the long-term survival for patients with less than 6 involved lymph nodes is 17.5 months. Therefore surgical resection for these patients seems to be justified. After induction therapy a rigorous restaging should be performed to rule out persisting multilevel N2 disease.