Do skip-N2 metastases significantly impact overall survival and disease-free interval in N2 NSCLC patients? A multicenter analysis

INTRODUCTION

Skip-N2 metastasis (N0N2), thus N2 metastasis in the absence of N1 metastasis, occur in approximately 20-30% of non-small cell lung cancer patients. N0N2 patients have a better prognosis than continuous-N2 metastasis (N1N2) patients following surgery. However, this effect remains controversial.Therefore, we conducted a multicentre study to compare the long-term survival and disease-free interval (DFI) of N1N2- and N0N2 patients.

METHODS

One- and three -year survival rates were measured. Kaplan-Meier curves and a Cox proportional hazards model assessed survival and were used to identify prognostic factors for overall survival. In addition, we performed propensity score matching (PSM) to rule out confounding factors. All patients received adjuvant chemoradiation therapy according to European guidelines.

RESULTS

Between January 2010 and December 2020, 218 stage IIIA/B N2 patients were included in our analysis. The Cox regression analysis revealed that N1N2 significantly influenced the overall survival rate. Before PSM, N1N2 patients showed significantly more metastatic lymph nodes (p < 0.001) and significantly larger tumors (p = 0.05). After PSM, baseline characteristics did not differ between groups. Before and after PSM, N0N2 patients showed significantly better one- (p = 0.01; p = 0.009), -three-year (p < 0.001) and survival rates than N1N2 patients. Furthermore, N0N2 patients showed significantly longer DFI than N1N2 patients before and after PSM (p < 000.1).

CONCLUSION

Prior- and after PSM analysis, N0N2 patients were confirmed to have better survival and DFI than N1N2 patients. Our results demonstrate that stage IIIA/B N2 patients are heterogeneous and would benefit from a more precise subdivision and differential treatment.

Prognostic impact of lymph node spreading pattern in N2 NSCLC patients

BACKGROUND

One-third of non-small cell lung cancer (NSCLC) patients are diagnosed with locally advanced disease. Long-term survival in stage IIIA/B-N2 remains poor; this may also be due to lymph node spreading pattern. Therefore, we compared the overall survival of stage IIIA/B-N2 patients with superior mediastinal lymph nodes (SML) with infracarinal- or inferior mediastinal lymph nodes (IML) and with multilevel disease (MLD).

RESEARCH DESIGN AND METHODS

One-, three-and five-year survival rates were measured. Kaplan-Meier curves and Cox proportional hazards model assessed survival and were used to identify prognostic factors.

RESULTS

We reviewed data of stage IIIA/B-N2 patients (n = 129) who underwent surgery for NSCLC between 2012 and 2020. Patients with SML (n = 62) were compared to ILM (n = 37) and MLD (n = 30). SML patients showed significantly better one- (SML: 95.2% vs. IML: 78.6% vs. MLD: 69.4%, p = 0.03), three- (78.8% vs. 27.7 vs. 13.3%; p = <0.001) and five-year (61.1% vs. 17.1 vs. 3%; p < 0.001) survival rates, than IML and MLD patients. Kaplan-Meier curves showed prolonged overall survival for SML patients (log-rank SML, ILM, MLD p < 0.0001).

CONCLUSIONS

This study showed significantly better long-term survival of SML patients than IML and MLD patients. The long-term survival of ILM and MLD patients was equally poor.