Risk factors for relapse of resectable pathologic N2 non small lung cancer and prediction model for time-to-progression

Role of skip N2 lymph node metastasis for patients with the stage III-N2 lung adenocarcinoma: a propensity score matching analysis

PURPOSE

Recent studies have indicated some differences in the prognosis of patients with stage III-N2 lung adenocarcinoma, and the prognosis of patients with skip N2 lymph node metastasis (SKN2) is good. This study grouped patients with stage III-N2 lung adenocarcinoma by propensity score matching (PSM) to evaluate the impact of SKN2 on the prognosis of these patients.

METHODS

The clinical data for patients who underwent radical lobectomy and had a postoperative pathological diagnosis of stage III-N2 lung adenocarcinoma at our centre from 2016 to 2018 were collected, and PSM was performed at a ratio of 1:1.

RESULTS

A total of 456 patients were enrolled in this study. After PSM, 112 patients were included in the SKN2 group, and 112 patients were included in the non-SKN2 group. When comparing the SKN2 group with the non-SKN2 group, the 3-year OS rate was (71.4% vs. 12.5%, p < 0.001), and the 3-year DFS rate was (35.7% vs. 5.4%, p < 0.001). It is further divided into four groups:single-station SKN2 (N2a1),Multi-station SKN2 (N2a2),single-station non-SKN2 (N2b1) and Multi-station non-SKN2 (N2b2).The 3-year OS and DFS rates of skip lymph node metastasis were better than those of non-skip lymph node metastasis(OS:N2a1 vs. N2b1 68.4% vs. 23.5%,p < 0.001;N2a2 vs. N2b2 73.0% vs. 7.7%,p < 0.001)(DFS:N2a1 vs. N2b1 68.4% vs. 5.9%,p < 0.001;N2a2 vs. N2b2 62.2% vs. 5.1%,p < 0.001), regardless of the number of N2 station(OS:N2a1 vs. N2a2 68.4% vs. 73.0%,p = 0.584;N2b1 vs. N2b2 23.5% vs. 7.7%,p = 0.051). On multivariate analysis, sex (p = 0.008) ,Vascular tumour thrombus(p = 0.047),size(p = 0.002)and SKN2 (p < 0.001) were independent predictors of OS.

CONCLUSION

For patients with stage III-N2 lung adenocarcinoma, the prognosis of SKN2 patients is better than non-SKN2 patients', and SKN2 may be used as an important factor in the N2 subgroup classification in future TNM staging.

Postoperative long-term survival of non-small cell lung cancer patients with skip-N2 metastases

OBJECTIVE

Radical lymphadenectomy is crucial in operations for non-small cell lung cancer (NSCLC). Usually pN1 and pN2 lymph nodes are affected consecutively (N1N2). Nevertheless, pN2 metastases may also occur in the absence of pN1 as skip-N2 metastases (N0N2). Here we compare the long-term survival of N1N2- and N0N2 patients.

MATERIALS AND METHODS

464 patients underwent surgery for NSCLC at our institution between 2012 and 2017. We retrospectively reviewed data of pN2 stage patients (n = 68). Patients with N1N2 (n = 39) were compared to N0N2 (n = 29) patients. 1-, 3-and 5-year survival rates were measured. Survival was assessed by Kaplan-Meier curves and the cox proportional hazards model was used to identify prognostic factors for overall survival. All patients received adjuvant chemoradiation therapy according to European guidelines.

RESULTS

The baseline characteristics did not differ between groups. We observed no differences in the histology, localization, or gender in our cohort. N0N2 patients showed significantly better 1- (N1N2: 82.4% vs. N0N2 100%; p = 0.001), 3- (14.7% vs. 63.6%; p=<0.001) and 5-year (9.4% vs. 43.8%; p = 0.001) survival rates. Tumor size (Hazard ratio (HR) 1.46, Confidence interval (CI 95%) 1.03-2.04; p = 0.03) and the occurrence of N1N2 (HR 4.26, CI 2.04-8.91; p < 0.0001) were independent prognostic factors for worse long-term survival. The Kaplan-Meier curves showed a reduced overall survival for N1N2 patients (log-rank N1N2, N0N2 p < 0.0001).

CONCLUSION

N1N2 patients have a significantly worse prognosis compared to N0N2 patients. This will aid to classify the heterogeneous pN2-NSCLC patient population more precisely. Further, multimodal therapy should be considered for N1N2 patients.

Role of Skip Mediastinal Lymph Node Metastasis for Patients With Resectable Non-small-cell Lung Cancer: A Propensity Score Matching Analysis

BACKGROUND

N2 disease represents a heterogeneous group of non-small-cell lung cancer (NSCLC) with varying 5-year overall survival (OS) rates. The skip N2 phenomenon is quite frequent, and its prognostic impact remains a matter of debate. The aim of this study is to further assess the clinical significance and prognostic value of skip N2 disease using propensity score matching.

PATIENTS AND METHODS

The study cohort included 437 patients with stage pN2 NSCLC who underwent resection from 2005 to 2011. Differences in clinicopathologic characteristics were identified in the overall cohort. The effect of skip N2 on OS was assessed, stratified by histology, tumor size, N2 involved stations, and T stage after propensity score matching.

RESULTS

A total of 130 patients had skip N2 diseases in our study. Skip N2 metastasis was associated with age, tumor size, histology, and number of involved N2 stations. Matching of 130 pairs of patients showed that skip N2 was associated with a significantly better 5-year OS rate when compared with non-skip N2 disease (42.7% vs. 25.3%; P = .004), and OS is significantly better in the patients with tumor size of ≤ 3 cm (P = .014) or patients with single N2 station involvement (P = .002). Skip N2 conferred a significantly better OS in stage IIIA (P = .026) and IIIB (P = .029) disease.

CONCLUSION

The presence of skip N2 metastasis was a good prognostic factor of resectable N2 disease. N2 disease may be classified into more subgroups in the revision of the current tumor-lymph node-metastasis (TNM) system.

Food for thought: Autophagy researcher wins 2016 Nobel Prize in Physiology or Medicine

This special edition of the Biomedical Journal honors the awarding of the 2016 Nobel Prize in Physiology and Medicine to Yoshinori Ohsumi for his pioneering work on elucidating the mechanisms of autophagy. We also highlight a study reporting a new and simple animal model for a widespread surgical technique called interbody spinal fusion. Finally, this issue also includes two articles reporting protocols that could produce specific cell types for cell based therapies.