Modifying gas transfer membranes with nanoscale zero-valent iron: effects on membrane material properties, treatment performance, and biofilm thickness.

Excessive membrane biofilm growth on membrane fibers depends on various factors, with membrane properties playing a pivotal role in influencing microbial affinity for the membrane. To investigate the antibacterial impact of nano-sized zero-valent iron (nZVI) on membrane biofilm structure, pristine (polyvinylidene fluoride (PVDF)) only: HF-0 (PVDF:20/nZVI:0 w/w) and four gas transfer membranes (PVDF:nZVI at different concentrations: HF-1 (PVDF:20/nZVI:0.25 w/w), HF-2 (PVDF:20/nZVI:0.50 w/w), HF-3 (PVDF:20/nZVI:0.75 w/w), HF-4 (PVDF:20/nZVI:1.0 w/w)) were produced. These membranes were assessed for surface morphology, porosity, gas permeability, and biofilm thickness, which ultimately affect biochemical reaction rates in membrane biofilm reactors (MBfRs). Various MBfRs utilizing these gas transfer membranes were operated at different hydraulic retention times (HRTs) and oxygen pressures to assess chemical oxygen demand (COD) removal efficiency and nitrification performance. Incorporating nZVI into the PVDF polymer solution increased surface hydrophilicity and porosity but reduced Young's Modulus and oxygen diffusion coefficients. Confocal laser scanning microscopy (CLSM) analysis revealed an average biofilm thickness of 700 µm in HF-0, HF-1, and HF-3, with a 100 µm decrease in HF-2, even though Escherichia coli growth was observed in HF-3 fibers. Regardless of nZVI dosage, a significant decline in COD removal and nitrification rates occurred at low HRTs and gas pressures.

Survival Effect of Surgery in Patients with Stage IIIB/N2 Non-small Cell Lung Cancer: A Comparative Study with Definitive Chemoradiotherapy.

OBJECTIVE: We compared the survival outcomes of surgery within multimodality treatment regimens with the outcomes of definitive chemoradiation treatments in patients diagnosed with clinical (c) IIIB/N2 non-small cell lung cancer (NSCLC). We investigated whether surgery within multimodality treatment provides a survival advantage at this stage. MATERIAL AND METHODS: Data from 79 patients with cIIIB/N2 between 2009 and 2016 were analyzed retrospectively. While the surgery was performed after neoadjuvant therapy in 51 cases (IIIB/Surgery Group), definitive chemotherapy ± radiotherapy was applied in 28 cases (IIIB/Definitive Group). RESULTS: In cIIIB/N2 cases, the 5-year overall survival (OS) was 27.4%, with a median OS of 24.6 months. The 5-year OS of the IIIB/ Surgery Group was 27.3% (median survival 22.5 months), while it was 28.6% (median survival 29.1 months) in the IIIB/Definitive Group (P = .387, HR = 0.798, 95% CI, 0.485-1.313). Although there was a survival advantage in the group with a pathological complete response (PCR) after surgery (n = 14) compared to the group that did not (n = 37), the observed difference was not statistically significant. (5-year OS; 42.9% vs. 18.5%, P = .104). Additionally, there was no statistically significant difference between the survival of PCR patients and the IIIB/Definitive Group in terms of OS (P = .488). CONCLUSION: Surgery performed within multimodality treatment regimens in selected cIIIB/N2 cases did not provide a survival advantage over definitive chemoradiation treatments.

Time-resolved in situ nanoparticle size evolution during magnetron sputtering onto liquids.

Despite extensive research since 1996, there are still open questions regarding the primary location of the nucleation process, the growth mechanism of the nanoparticles (NPs), and the influence of the liquid properties on the ultimate size of the NPs for the magnetron sputtering of metals onto liquids. Hence, for the first time to the authors' knowledge, the particle size evolution is in situ and in real-time examined during and after the sputtering of the silver atoms onto silicone oil, i.e., Sputtering onto Liquids (SoL) process. The particle size distribution (PSD) is measured via the Light Extinction Spectroscopy (LES) technique, and the deposition rate and stirring speed effects on the PSDs are analyzed. Based on De Brouckere mean diameters, the size evolution of silver nanoparticles (Ag NPs) over time is monitored. Ag NPs bigger than 20 nm are detected, and the PSDs are shown to be poly-disperse, which is also supported by the ex situ TEM measurements and in situ time-resolved absorption spectra. Moreover, it is shown that aggregation and growth of Ag NPs occur both at the plasma-liquid interface and inside the silicone oil during and after the magnetron sputtering. Despite the same amount of deposited silver, the growth kinetics of Ag NPs in silicone oil vary at different deposition rates. In particular, at higher deposition rates, larger NPs are formed. Stirring is seen to help disaggregate the particle lumps. Faster stirring does not substantially influence the final size but promotes the formation of smaller NPs (<20 nm). Also, low colloidal stability of Ag NPs in silicone oil is observed.

Can stage-IIB lung cancer be divided into subgroups in terms of prognosis? A modelling study.

INTRODUCTION: Whether changes should be made to the TNM classification of non-small cell lung cancer (NSCLC) according to the newly proposed nodal classification is unclear. We aim to compare the survival between stage-IIB subsets using a modelling study performed using the newly proposed nodal classification. PATIENTS AND METHODS: A total of 682 patients with stage-IIB NSCLC based on the 8th TNM classification were analysed. Hazard ratio (HR) values calculated from survival comparisons between stage-IIB subgroups were used to create a model for patients with stage-IIB NSCLC, and modelling was performed according to the HR values that were close to each other. RESULTS: Patients with T1N1a cancer had the best survival rate (58.2%), whereas the worst prognosis was observed in those with T2bN1b cancer (39.2%). The models were created using the following HR results: Model A (T1N1a, n = 85; 12.4%), Model B (T2a/T2bN1a and T3N0, n = 438; 64.2%), and Model C (T1/T2a/T2bN1b, n = 159; 23.4%). There was a significant difference between the models in terms of overall survival (p = 0.03). The median survival time was 69 months in Model A, 56 months in Model B, and 47 months in Model C (Model A vs. Model B, p = 0.224; Model A vs. Model C, p = 0.01; and Model B vs. Model C, p = 0.04). Multivariate analysis showed that age (p < 0.001), pleural invasion (p < 0.001), and the developed modelling system (p = 0.02) were independently negative prognostic factors. CONCLUSION: There was a prognostic difference between stage-IIB subsets in NSCLC patients. The model created for stage-IIB lung cancer showed a high discriminatory power for prognosis.

Role of Nanoparticles in Nanofluid Droplet Impact on Solid Surfaces.

Splashing of a liquid droplet onto a substrate, while ubiquitous, sits at the intersection of several key fluid mechanical regions. Typically, this problem is often simplified to the transition between spreading and splashing, even for splashing on complex surfaces. Recently, there has been increased interest in using not just pure liquids but also nanofluids in applications such as spray cooling. While the addition of a few percent of nanoparticles to a Newtonian fluid does not change its apparent viscosity, the influence of the nanoparticles on the splashing transition is pronounced. We often view splashing in terms of fluid mechanics where a simple material is subjected to a complex flow and the fluid can be simply characterized by a Newtonian viscosity. For nanofluids, we have an apparently simple material in a complex flow, but the results show that the impact of the particles is nontrivial. This implies that we must now combine some of the insights we obtain from studying the rheological properties of nanosuspensions with this already complex problem.

Comparison of 6th, 7th, and 8th editions of the TNM staging in non-small cell lung cancer patients: Validation of the 8th edition of TNM staging.

Background: In this study, we aimed to evaluate the effects of the transition from the 6th edition of the Tumor, Node, Metastasis (TNM) staging system to the 7th edition, and from the 7th edition to the 8th edition by comparing the stage migrations. We also aimed to externally validate the 8th edition of the TNM staging system. Methods: Between September 2005 and June 2015, a total of 1,077 patients (986 males, 91 females; mean age: 59.6±8.3 years; range, 35 to 84 years) with non-small cell lung cancer who underwent lung resection were retrospectively analyzed. We re-staged patients according to 6th, 7th, and 8th TNM staging and compared the stage migrations of cases among the three staging systems. Results: Stage migration in the transition to the 7th edition of the TNM staging system was observed in 368 (34.1%) patients whereas it was observed in 541 (50.2%) patients in the transition to the 8th edition (p<0.001). The rate of upstaging in transition to the 7th edition staging system was 50.2% (n=185), whereas it was 98.1% (n=531) for the transition to the 8th edition (p<0.001). The survival rates of Stages 1B, 2B and 3A increased with transition to the 7th edition and the survival rates of Stages 1B, 2A, 2B, 3A, and 3B increased with the transition to the 8th edition. The best stratification in the survival curves in the 6th edition was between 1B-1A and 3B-3A. In the 7th edition, it occurred between 1B-1A, 3A-2B and 3B-3A and, in the 8th edition, between 1B-1A and 3B-3A. Conclusion: Stratification according to the 7th edition showed better prognostic validity compared to the 6th edition; and that of the 8th edition was better compared to the 7th edition.

Is there any change in disease presentation and surgical outcomes in patients with pulmonary aspergilloma? An evaluation of the time trend.

Background: This study aims to investigate the changes in the clinical and radiological presentations of pulmonary aspergilloma in patients undergoing surgery and to evaluate changes in the surgical outcomes over time. Methods: Between January 2000 and January 2020, a total of 88 patients (69 males, 19 females; mean age: 45.4±11.2 years; range, 17 to 70 years) who underwent surgery for pulmonary aspergilloma were retrospectively analyzed. Surgeries performed were divided into two groups based on their chronological order: first period (from 2000 to 2010, n=44) and second period (from 2010 to 2020, n=44). Results: The most frequent underlying disorder was tuberculosis (72.7%), whereas 10 patients did not have any predisposing conditions for pulmonary aspergilloma. Regarding the aspects of radiological imaging and operative findings, 22 patients had simple aspergilloma and 66 patients had complex aspergilloma. Complications and mortality rates were 33.0% and 5.7%, respectively. A statistical downward was observed in the second period compared to that in the first period regarding the rate of patients with tuberculosis history (61.4% vs. 84.1%, p=0.01). There were more patients who did not have any predisposing conditions for pulmonary aspergilloma in the second period and in the simple aspergilloma group (p=0.04 and p<0.001, respectively). Simple aspergilloma was often observed in the second period than that in the first period (31.8% vs. 18.2%). There was no significant difference between the periods regarding the type of surgical resection (p=0.506), whereas in the simple aspergilloma group, more patients underwent wedge resection (p<0.001). There were no significant differences between the periods and radiological groups in terms of complications and mortality. Patients who underwent pneumonectomy had significantly higher rates of complications and mortality (p=0.01 and p=0.03, respectively). Conclusion: Although pulmonary aspergilloma patients who underwent surgery in the last 10 years had a lower history of tuberculosis than those who were operated in the previous 10 years, there was no change in postoperative complications and mortality rates. An increase in simple aspergilloma prevalence may reduce the rate of surgical morbidity.

Factors affecting survival after anatomical lung resection in pulmonary aspergilloma: Our 10-year single institution experience.

Background: The aim of this study was to investigate the long-term outcomes of patients who underwent anatomic lung resection for pulmonary aspergilloma and to evaluate the prognostic factors affecting early postoperative morbidity. Methods: Between January 2007 and January 2017, we retrospectively evaluated a total of 55 patients (40 males, 15 females; mean age: 44.6 years; range, 18 to 75 years) who underwent lobectomy and pneumonectomy for pulmonary aspergilloma. All patients were evaluated for simple or complex aspergilloma based on imaging and thoracotomy findings. Results: Thirty-two (58.2%) patients presented with hemoptysis. Seven (12.7%) patients underwent emergency surgery due to massive hemoptysis. Postoperative morbidity was observed in 15 (27.3%) patients. Prognostic factors that had an effect on morbidity were resection type, Charlson Comorbidity Index >3, and massive hemoptysis (p<0.05). There was no intra- or postoperative mortality. The five-year survival rate was 89.4%. None of the factors evaluated in the study were associated with survival. Conclusion: The main finding of this study is the absence of mortality after surgical treatment for pulmonary aspergilloma. The success of surgical treatment depends on the management of postoperative complications.

Does anatomical location-based metastatic lymph node density affect prognosis in lung cancer patients?

OBJECTIVES: The newly proposed N subclassification (new-N) was compared with the combined anatomical location and ratio of the number of metastatic lymph nodes to the total number of resected lymph nodes (anatomic-LNR) in terms of prognosis in resected lung cancer patients. METHODS: Between 2005 and 2018, 961 patients who underwent lung cancer resection were catergorized into the pN1-single (N1a; n = 281), pN1-multiple (N1b; n = 182), pN2-single with skip metastasis (N2a1; n = 116), pN2-single with N1 metastasis (N2a2; n = 222) and pN2-multiple (N2b; n = 160) groups based on new-N. The optimal cut-off points for survival in pN1 and pN2 patients were determined using the best sensitivity and specificity scores, calculated using receiver operating characteristic analysis. RESULTS: The difference in survival between N1a and N1b patients was statistically significant (P = 0.001), but there was no significant difference in the survival rates of N1b and N2a1 (P = 0.52). The survival curves for N2a1 and N2a2 patients almost overlapped (P = 0.143). N2a2 patients showed a better survival rate than N2b patients, with no significant difference (P = 0.132). The cut-off points for LNR were 0.10 and 0.25 for pN1 and pN2 patients, respectively, according to receiver operating characteristic analysis for survival. Based on receiver operating characteristic analysis, pN patients were categorized into the N1-lowLNR (n = 232), N1-highLNR (n = 231), N2-lowLNR (n = 266) and N2-highLNR (n = 232) groups. The 5-year survival rate was 62.9%, 49.8%, 41.1% and 27.1% for N1-lowLNR, N1-highLNR, N2-lowLNR and N2-highLNR, respectively (P < 0.001). CONCLUSIONS: LowLNR is associated with better survival than highLNR in resected lung cancer patients. Anatomic-LNR shows a high discriminatory power for prognosis.

Is the Yedikule-solitary pulmonary nodule malignancy risk score sufficient to predict malignancy? An internal validation study.

OBJECTIVES: We aimed to develop a malignancy risk score model for solitary pulmonary nodules (SPNs) using the demographic, radiological and clinical characteristics of patients in our centre. The model was then internally validated for malignancy risk estimation. METHODS: A total of 270 consecutive patients who underwent surgery for SPN between June 2017 and May 2019 were retrospectively analysed. Using the receiver operating characteristic curve analysis, cut-off values were determined for radiological tumour diameter, maximum standardized uptake value and the Brock University probability of malignancy (BU-PM) model. The Yedikule-SPN malignancy risk model was developed using these cut-off values and demographic, radiological and clinical criteria in the first 180 patients (study cohort) and internally validated with the next 90 patients (validation cohort). The Yedikule-SPN model was then compared with the BU-PM model in terms of malignancy prediction. RESULTS: Malignancy was reported in 171 patients (63.3%). Maximum standardized uptake value and BU-PM scores were sufficient to predict malignancy (P < 0.001 for both), while the effectiveness of nodule size determined on thoracic computed tomography did not reach statistical significance (P = 0.09). When the Yedikule-SPN model developed with the study cohort was applied to the validation cohort, it significantly predicted malignancy (area under the receiver operating characteristic curve: 0.883, 95% confidence interval: 0.827-0.957, P < 0.001). Comparison of patients in the validation group with Yedikule-SPN scores above (n = 53) and below (n = 37) the cut-off value of 65.75 showed that the malignancy rate was significantly higher among patients with Yedikule-SPN score over 65.75 (86.8% vs 21.6%, P < 0.001, odds ratio = 23.821, 95% confidence interval: 7.805-72.701). When compared with the BU-PM model in all patients, the Yedikule-SPN model tended to be a better predictor of malignancy (P = 0.06). CONCLUSIONS: The internally validated Yedikule-SPN model is also a good predictor of the malignancy of SPN(s). Prospective and multicentre external validation studies with large patients' cohorts are needed.

The prognostic impact of the mediastinal fat tissue invasion in patients with non-small cell lung cancer.

BACKGROUND: The prognosis of the mediastinal fat tissue invasion in non-small cell lung cancer (NSCLC) patients has not yet been clearly defined. The present study aimed to investigate the prognostic impact of the mediastinal fat tissue invasion in NSCLC patients. METHOD: We analyzed 36 patients who were found mediastinal fat tissue invasion by pathological evaluation (mediastinal fat group) and 248 patients who were classified as T4-NSCLC according to the 8th TNM classification (T4 group; invasion of other mediastinal structures in 78 patients, ipsilateral different lobe satellite pulmonary nodule in 32 patients, and tumor diameter > 7 cm in 138 patients). RESULT: Resection was regarded as complete (R0) in 255 patients (89.7%). Mediastinal fat group showed significantly higher incidence of incomplete resection (R1) and more left-sided tumors than the T4 group (p = 0.01, and p = 0.002, respectively). The survival was better in T4 group than mediastinal fat group (median 57 months versus 31 months), although it was not significant (p = 0.205). Even when only N0/1 or R0 patients were analyzed, the survival was not different between two groups (p = 0.420, and p = 0.418, respectively). 5-year survival rates for T4 subcategories (invasion of other structures, ipsilateral different lobe pulmonary nodule, and tumor diameter > 7 cm) were 39.4%, 41.9%, and 50.3%, respectively (p = 0.109). Multivariate analysis showed that age (p < 0.0001), nodal status (p = 0.0003), and complete resection (p < 0.0001) were independently influenced survival. CONCLUSION: There is no significant difference in the prognosis between mediastinal fat tissue invasion and T4 disease in NSCLC patients.

Prognostic factors for survival in patients with completely resected pN2 non-small-cell lung cancer.

BACKGROUND: This study examined the incidence of pathologic N2 (pN2) non-small-cell lung cancer (NSCLC) and prognostic factors affecting survival of these patients. METHODS: A total of 119 patients who underwent surgery for NSCLC (lobectomy and pneumonectomy) between January 2008 and December 2016 were evaluated retrospectively. The patients with pN2 included in this study were assessed in two groups; single pN2 and multiple pN2. RESULTS: The most common type of resection was lobectomy (56.3%). Ninety-four patients (79%) received adjuvant therapy. Eighty-six patients (72.3%) had single-station pN2 and 33 (27.7%) had multiple pN2. The 5-year survival rates were 29.3% overall, 38.6% in single-station pN2, and 11% in multiple-station pN2 (hazard ratio [HR]: 0.581, p = .037). There was no statistically significant difference in 5-year survival rates between patients with pN1N2 and those with pN0N2 involvement (39.1% vs. 37.1%) (p = .625). Not receiving adjuvant therapy was associated with poor survival prognosis (HR: 8.2 p < .001). The 5-year survival rate was 36.2% among patients with pN2 involvement with 2 or more positive lymph nodes and 19.5% among those with fewer than 2 positive lymph nodes (HR: 0.83, p = .463). CONCLUSIONS: The most significant prognostic factors associated with survival were pN2 status. Non-skip metastases (pN1N2) and positive lymph node count were not associated with prognosis.

Is There a Prognostic Difference Between Stage IIIA Subgroups in Lung Cancer?

BACKGROUND: Treatment of stage IIIA lung cancer remains controversial because it includes a very heterogeneous group of patients. The purpose of our study was to compare survival between stage IIIA subsets and to externally validate our results with another center's database. METHODS: Patients with completely resected stage IIIA/B lung cancer were retrospectively analyzed. There were 424 patients with stage IIIA and 82 patients with stage IIIB (T3/4 N2) (study cohort). Stage IIIA was divided into 2 subsets according to the tumor localization and tumor size (T3 N1-T4 N0/1, IIIA-T group; n = 308) and the extension of nodal disease (T1/2 N2, IIIA-N2 group; n = 116). The study cohort results were used to create a model for stage IIIA patients, which was validated with another center's database (validation cohort). RESULTS: The multivariate analyses showed age, stage IIIB, and pN2 were independent negative prognostic factors (P < .0001). Survival at 5 years was 51.3% (median, 64 months) for patients in the IIIA-T group and was 25.7% (median, 31 months) in the IIIA-N2 patients (hazard ratio, 1.834; P < .0001). There was no statistical difference in survival between the IIIA-N2 and stage IIIB groups (25.7% vs 25.3%, P = .442). The created model was performed on patients in the validation cohort as a model IIIA-T (T3 N1-T4 N0/1, n = 139) and model IIIA-N2 (T1/2 N2, n = 104). Model IIIA-T patients had a statistically better survival rate than model IIIA-N2 patients (median, 62 months vs 37 months; hazard ratio, 1.707, P < 0.001). CONCLUSIONS: There is a prognostic difference between stage IIIA subgroups in lung cancer patients who undergo surgical treatment.

Does the carinal involvement have the same surgical outcome as the main bronchus involvement in patients with non-small cell lung cancer?

OBJECTIVE: Carinal and main bronchus involvement were compared in terms of the survival of patients with N0-1 non-small cell lung cancer (NSCLC). METHODS: Sixty-six NSCLC patients who underwent complete surgical carinal resection/reconstruction (Carina group) and complete resection because of main bronchus involvement (Main Bronchus group) between 2006 and 2016 were retrospectively analyzed. The Carina group included 30 patients and the Main Bronchus group included 36. In the Carina group, conditions other than carinal involvement that rendered patients pathological (p) T4, and in the Main Bronchus group, conditions that would upstage the pT status from pT2 were excluded. Patients with mediastinal lymph node metastases were excluded. Thus, an isolated main bronchial invasion and isolated carinal invasion patient population was tried to be obtained. RESULTS: The overall 5-year survival rate was 49.4% (median 61.5 ± 19.9 months). The 5-year survival rates of patients in the Carina group was 49.2% (median 63.3 months), and that of patients in the Main Bronchus group was 46.4% (median 55.9 months). The difference between survival rates was not statistically significant (p = 0.761). The survival rates of pN0 and pN1 patients also did not differ significantly (63.2% vs. 45.5%, p = 0.207). Recurrence was significantly more common in the Main Bronchus group than the Carina group (28.1% vs. 7.1%; p = 0.04). CONCLUSIONS: Isolated carinal invasion had a comparable outcome to isolated main bronchus invasion in pN0-1 patients with NSCLC who are undergoing anatomical surgical resection.

Prognostic Factors and Survival in Resected T4 Non-small Cell Lung Cancer: Is There Any Difference in the T4 Subgroups?

INTRODUCTION: The eighth edition of the TNM classification revised the subgroups of T4 non-small cell lung cancer (NSCLC). This study aimed to compare the T4-NSCLC subgroups that underwent surgical treatment in terms of mortality, morbidity, survival, and prognostic factors based on the new classification. MATERIALS AND METHODS: Between 2000 and 2014, a total of 284 T4-NSCLC patients who underwent lung resection (mediastinal organ invasion, n = 114; ipsilateral different lobe tumors, n = 32; and tumors larger than 7 cm, n = 138) were included in the present study. RESULTS: Surgical mortality and morbidity were 5.6% (n = 16) and 23.9% (n = 68), respectively. The 5-year survival rates were 46% for ipsilateral different lobe tumors, 45.4% for tumours larger than 7 cm, and 36.6% for mediastinal organ invasion (28% for patients with heart/atrium invasion, 43.3% for carina invasion, 37.5% for large vessel invasion) (p = 0.223). Age above 65 (p = 0.002, HR = 1.781), pN2 versus pN0/1 (p < 0.0001, HR = 2.564), incomplete resection (p = 0.003, HR = 2.297), and pneumonectomy (p = 0.02, HR = 1.524) were identified as poor prognostic survival factors. According to multivariate analysis, mediastinal lymph node metastasis (p = 0.001) and incomplete resection (p = 0.0026) were the independent negative risk factors for survival. CONCLUSION: According to the results of our study, surgical treatment is a good option in T4-NSCLC patients who have no mediastinal lymph node metastasis and are completely resectable. There is no difference in terms of survival among the T4 subgroups. The eighth edition of the TNM classification has a better prognostic definition than the previous version.

A Comparison of the Currently Used Nodal Stage Classification with the Number of Metastatic Lymph Nodes and the Number of Metastatic Lymph Node Stations for Non-Small Cell Lung Cancer; Which of These Is the Best Prognostic Factor?

OBJECTIVES: We aimed to compare the currently used nodal staging system (pN) with the number of metastatic lymph node (LN) stations (sN) and the number of metastatic LNs (nN) on survival in patients with NSCLC. METHODS: Between 2010 and 2017, 1038 patients resected for NSCLC were analyzed. We performed three-different stratifications of LN status assessment: pN-category (pN0, pN1 and pN2); sN-category (sN0, sN1; one station metastasis, sN2; two-three stations metastases, and sN3; ≥ 4 stations metastasis); nN-category (nN0, nN1; one-three LNs metastasis, nN2; four-six Lns metastasis, and nN3; ≥ 7 LNs metastasis). RESULTS: Five-year survival rate was 70.1% for N0 in all classifications. It was 54.3% for pN1, and 26.4% for pN2 (p < 0.0001). Five-year survival rates for N1, N2, and N3 categories were 54.1%, 42.4% and 16.1% according to sN, and 51.4%, 36.1%, and 7.9% according to nN, respectively (p < 0.0001). In multivariate analysis, sN and nN were independent risk factors such as pN (p < 0.0001). Hazard ratios versus N0 for N1, N2, and N3 were more significant for sN and nN than pN (1.597, 2.176, and, 3.883 for sN, 1.645, 2.658, and, 4.118 for nN, and 1.576, 3.222 for pN, respectively). When the subcategories of sN and nN were divided into pN1 and pN2 subgroups, the anatomic location of the LN involvement lost importance as tumor burden and tumor spreading increased. CONCLUSION: The number of metastatic LN stations and the number of metastatic LNs are better prognostic factors than currently used nodal classification in NSCLC.