Prognostic significance of surgical-pathologic N1 lymph node involvement in non-small cell lung cancer

Resectable non-stage IV nonsmall cell lung cancer: the surgical perspective

Surgery remains an essential element of the multimodality radical treatment of patients with early-stage nonsmall cell lung cancer. In addition, thoracic surgery is one of the key specialties involved in the lung cancer tumour board. The importance of the surgeon in the setting of a multidisciplinary panel is ever-increasing in light of the crucial concept of resectability, which is at the base of patient selection for neoadjuvant/adjuvant treatments within trials and in real-world practice. This review covers some of the topics which are relevant in the daily practice of a thoracic oncological surgeon and should also be known by the nonsurgical members of the tumour board. It covers the following topics: the pre-operative selection of the surgical candidate in terms of fitness in light of the ever-improving nonsurgical treatment alternatives unfit patients may benefit from; the definition of resectability, which is so important to include patients into trials and to select the most appropriate radical treatment; the impact of surgical access and surgical extension with the evolving role of minimally invasive surgery, sublobar resections and parenchymal-sparing sleeve resections to avoid pneumonectomy.

Benefit of adjuvant chemotherapy for resected pathologic N1 non-small cell lung cancer is unrecognized: A subgroup analysis of the JBR10 trial

Adjuvant chemotherapy is underutilized in clinical practice, in part, because its anticipated survival benefit is limited. We evaluated the impact of AC on overall and recurrence-free survival among completely resected pN1 NSCLC patients enrolled in the North American Intergroup phase III (JBR10) trial. A post-hoc subgroup analysis of pN1 NSCLC patients was performed. Participants were randomized to cisplatin+vinorelbine (AC) (n = 118) or observation (n = 116) following complete resection. The primary endpoint was overall survival (OS). The secondary endpoint was recurrence free survival (RFS). Kaplan-Meier methods were used to compare OS and RFS between the two treatment groups. Cox regression was used to identify factors associated with OS and RFS endpoints. Both groups had similar baseline characteristics. AC patients had improved 5-year OS (AC 61.4% vs observation 41.0%, log-rank p = .008) and 5-year RFS (AC 56.2% vs observation 39.9%, log-rank p = .011) rates compared to observation. Cox regression analyses confirmed the OS (HR 0.583, 95% CI 0.402-0.846, p = .005) and RFS (HR 0.573, 95% CI 0.395-0.830, p = .003) benefit associated with AC. AC was associated with a lower risk (HR 0.648, 95% CI 0.435-0.965, p = .0326) and a lower cumulative incidence (Subdistribution Hazard Ratio [SHR], 0.67, 95% CI 0.449-0.999, p = .0498) of lung cancer deaths. In the JBR10 trial, treatment with AC conferred a significant OS and RFS advantage over observation for pN1 NSCLC patients. These data suggest that pN1 NSCLC patients may experience a disproportionately greater clinical benefit from AC than the 6% survival advantage estimated by the LACE meta-analysis.

A Comprehensive Comparison of Different Nodal Subclassification Methods in Surgically Resected Non-Small-Cell Lung Cancer Patients

INTRODUCTION

The revision of the N descriptor in non-small-cell lung cancer has been widely discussed in the past few years. Many different subclassification methods based on number or location of lymph nodes have been proposed for better distinguishing different N patients. This study aimed to systematically collect them and provide a comprehensive comparison among different subclassification methods in a large cohort.

METHOD

Pathological N1 or N2 non-small-cell lung cancer patients undergoing surgical resection between 2005 and 2016 in the Western China Lung Cancer Database were retrospectively reviewed. A literature review was conducted to collect previous subclassification methods. Kaplan-Meier and multivariable Cox analyses were used to examine the prognostic performance of subclassification methods. Decision curve analysis, Akaike's information criterion, and area under the receiver operating curve concordance were also performed to evaluate the standardized net benefit of the subclassification methods.

RESULTS

A total of 1625 patients were identified in our cohort. Eight subclassification methods were collected from previous articles and further grouped into subclassification based on number categories (node number or station number), location categories (lymph node zone or chain) or combination of number and location categories. Subclassification based on combination of lymph node location and number tended to have better discrimination ability in multivariable Cox analysis. No significant superiority among the different subclassification methods was observed in the three statistical models.

CONCLUSION

Subclassification based on the combination of location and number could be used to provide a more accurate prognostic stratification in surgically resected NSCLC and is worth further validation.

The impacts of isolated N1 lymph nodes metastasis on prognosis in non-small cell lung cancer: A single-center experience

Background: This study aims to investigate long-term results related to N1 group metastases with respect to anatomical localization and many external parameters and to examine the effect of these parameters on prognosis in patients with in nonsmall cell lung cancer.

Methods: Between January 2006 and May 2019, a total of 52 patients (44 males, 8 females; mean age: 59.9±9.5 years; range, 42 to 80 years) who underwent lobectomy due to primary lung malignancy were retrospectively analyzed. The N1 lymph nodes were divided into three anatomical groups as hilar, peribronchial, and intraparenchymal. Demographic features, tumor features, follow-up characteristics, and survival and diseasefree survival parameters were analyzed for each group. The results were also examined in terms of number of metastasis, number of metastatic levels, rate of metastasis, and histopathological type.

Results: The five-year survival rate was 66.4% in the peribronchial group and 50% in the hilar group. The five-year disease-free survival rate was 45.7% in the peribronchial group and 37.5% in the hilar group. There was no statistically significant difference between the groups in terms of survival and disease-free survival for anatomical localization, number of metastasis, number of metastatic levels, rate of metastasis, and histopathological type (p>0.05 for all).

Conclusion: The structure that would be formed by examining N1 in terms of parameters such as subtitle levels, number of metastasis, number of metastatic stations, rate of metastasis or combinations of these would have a more impact on the decisions in the follow-up and treatment process in this patient population.

Peripheral Tumor Location Predicts a Favorable Prognosis in Patients with Resected Small Cell Lung Cancer

BACKGROUND

Small cell lung cancer (SCLC) is an aggressive malignancy. Surgical resection is currently only recommended for clinical stage I patients who have been carefully staged. The clinical outcomes of patients with resected SCLCs vary because the disease is highly heterogeneous, suggesting that selected patients could be considered for surgical resection depending on their clinical and/or molecular characteristics.

METHODS

We collected data on a retrospective cohort of 119 limited-stage SCLC patients who underwent lobectomy with mediastinal lymph node dissection from March 2013 to March 2020 at Harbin Medical University Cancer Hospital. Correlations were derived using Fisher's exact test. Models of 2-year and 3-year survival were evaluated by deriving the area under receiver operating characteristic curves. Kaplan-Meier and Cox regression analyses were used to evaluate significant differences between the survival curves and hazard ratios.

RESULTS

The median disease-free survival (DFS) was 35.9 months (range 0.9-105.3 months), and the median overall survival (OS) was 45.2 months (range 4.8-105.3 months). Univariate analysis showed that TNM stage was significantly correlated with DFS and OS. The 2-year disease-free rates of patients with stage I, II, and III disease were 76.4%, 50.5%, and 36.1%, respectively, and the 3-year OS rates were 75.9%, 57.7%, and 34.4%, respectively. In pN + patients, multiple (or multiple-station) lymph node involvement significantly increased recurrence and reduced survival compared with patients with single or single-station metastases. Patients with peripheral SCLCs evidenced significantly better DFS and OS than did patients with central tumors. Multivariate analysis showed that TNM stage and tumor location were independently prognostic in Chinese patients with resected limited-stage SCLC. A combination of TNM stage and tumor location was helpful for prognosis.

CONCLUSIONS

TNM stage and tumor location were independently prognostic in Chinese patients with resected SCLCs. Patient stratification by tumor location should inform the therapeutic strategy. The role of surgical resection for limited-stage SCLC patients must be reevaluated, as this may be appropriate for some patients.

Prognostic value of different N1 lymph node zones in pN1M0 non-small cell lung cancer: a systematic review and meta-analysis

The IASLC lymph node map grouped the lymph node stations into “zones” for prognostic analyses. In the N1 lymph nodes group, N1 nodes are divided into the Hilar/Interlobar zone (N1h) and Peripheral zone (N1p). There is no consensus on the different prognostic values of N1 lymph nodes in N1h and N1p. Therefore, we conducted a systematic review and meta-analysis to assess the survival difference between N1h and N1p in patients of pN1M0 NSCLC. Medline, the Cochrane Library, Embase, and the Web of science were systematically searched to identify relevant studies published up to April 4th, 2020. A retrospective and prospective cohort study comparing N1h versus N1p to the pN1M0 NSCLC was included. Hazard ratios (HRs) for OS were aggregated according to a fixed or random-effect model. Ten publications for 1946 patients of pN1M0 NSCLC were included for the meta-analysis.The 5-year OS was lower for patients with N1h (HR: 1.67, 95% CI 1.44–1.94; P < 0.001). The pooled 5-year OS in N1h and N1p were 40% and 56%, respectively. The patients in pN1M0 NSCLC have different survival according to different N1 lymph node zones involvement: patients with N1p metastasis have a better prognosis than those with N1h metastasis.

Prognostic significance of the N1 classification pattern: a meta-analysis of different subclassification methods

OBJECTIVES

The number of positive lymph node stations has been viewed as a subclassification in the N1 category in the new revision of tumour node metastasis (TNM) staging. However, the survival curve of these patients overlapped with that of some patients in the N2 categories. Our study focused on the prognostic significance of different subclassifications for N1 patients.

METHODS

We systematically searched PubMed, Ovid, Web of Science and the Cochrane Library on the topic of N1 lymph node dissection. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were used to assess the prognostic significance of N1 metastases. I2 statistics was used to evaluate heterogeneity among the studies: If significant heterogeneity existed (P ≤ 0.10; I2 >50%), a random effect model was adopted.

RESULTS

After a careful investigation, a total of 17 articles were included in the analysis. The results showed that patients with non-small-cell lung cancer with multistation N1 disease have worse survival compared with those with single-station N1 disease (HR 1.53, 95% CI 1.32-1.77; P < 0.001; I2 = 5.1%). No significant difference was observed between groups when we assessed the number of positive lymph nodes (single or multiple) (HR 1.25, 95% CI 0.96-1.64; P = 0.097; I2 = 72.5%). Patients with positive hilar zone lymph nodes had poorer survival than those limited to the intrapulmonary zone (HR 1.80, 95% CI 1.57-2.07; P < 0.001; I2 = 0%). A subgroup analysis conducted according to the different validated lymph node maps showed a stable result.

CONCLUSIONS

Our result confirmed the prognostic significance of the N1 subclassification based on station number. Meanwhile, location-based classifications, especially zone-based, were also identified as prognostically significant, which may need further confirmation and validation in the staged population.

Chemotherapy and Surgical Resection for N1 Positive Non-small Cell Lung Cancer: Better Than Expected Outcomes

N1-positive (T1-3, N1, M0) non-small cell lung cancer (NSCLC) represents a minority distribution (∼8%) of the approximately 234,000 diagnosed cases per year. As such, there is a paucity of modern high-quality data regarding outcomes following surgically-resected, stage N1-positive NSCLC. Randomized controlled trials from more than a decade ago have demonstrated a modest 5.4% survival benefit with adjuvant chemotherapy but have included heterogenous patient populations and stage distributions. Large database analyses have questioned the role of perioperative chemotherapy in resected patients with N1 disease, but without much granular detail regarding staging, quality of surgery, and chemotherapy. This single-institution study sought to evaluate the role of perioperative chemotherapy, specifically in N1-positive NSCLC patients. Data for all patients with surgically resected N1-positive NSCLC (T1-3, N1, M0) between 2006 and 2016 were collected for this study. Patients who underwent pneumonectomy were excluded from analysis. A retrospective chart review was conducted, and comprehensive clinicopathologic data were collected relative to staging, surgery, pathologic review, and perioperative oncology treatment. After exclusion criteria were applied, 148 patients with surgically resected, N1-positive disease (T1-3, N1, M0) remained for analysis. The majority of patients underwent lobectomy (75.0%), of which 55.4% underwent minimally invasive resection. There were no differences in postoperative complications, length of stay, number of lymph nodes sampled, or mortality associated with the surgery only and surgery with adjuvant therapy subgroups. 107 patients (72.3%) received adjuvant therapy, and this was associated with higher 5-year overall survival (62.8%) and disease-free survival (45.1%) than patients who underwent surgery only (33.9% overall survival at 5 years, P = 0.01; 22.4% disease-free survival at 5 years, P = 0.04). The presence of multistation N1 nodal metastases in patients was associated with lower 5-year overall survival (22.7%) and disease-free survival (5.6%) than patients with single-station N1 nodal metastasis (60.4% overall survival at 5 years, P = 0.003; 46.0% disease-free survival at 5 years, P < 0.001). On multivariable analysis, receiving any adjuvant chemotherapy was associated with improved overall survival and disease-free survival (Overall Survival HR 0.47, P < 0.01 | Disease-Free Survival HR 0.46, P <0.01). Multistation N1 disease was associated with significantly worse disease-free survival (HR 2.11, P = 0.04). Perioperative chemotherapy was associated with improved survival in N1-positive NSCLC, and the potential magnitude of benefit exceeded 25% in this study. Patients with single-station N1 lymph node metastasis were observed to have better disease-free survival.

Surgical Results in Pathological N1 Nonsmall Cell Lung Cancer

BACKGROUND

This retrospective study investigated the prognosis of patients with pathological N1 (pN1) nonsmall cell lung cancer (NSCLC).

METHODS

We included patients with pN1 NSCLC who underwent lobectomy or pneumonectomy with mediastinal lymph node dissection and achieved complete resection (R0) between January 2000 and December 2012. Patients who received neoadjuvant therapy were excluded.

RESULTS

A total of 249 patients were included. The mean age was 63.2 years, and 172 patients were males. Of the 249 patients, 200, 20, and 29 underwent lobectomy, bilobectomy, and pneumonectomy, respectively. The median observation period was 5.5 years. The 5-year overall survival (OS) rate was 64.6% (95% confidence interval: 58.3-70.4). Five-year OS rates were 79.8% for positive lymph nodes at station 13 or 14 (n = 57), 59.6% at station 12 (n = 72), 62.7% at station 11 (n = 69), and 56.9% at station 10 (n = 51) (log-rank test; p = 0.016); furthermore, the 5-year OS rate was 75.2% for patients with positive lymph nodes at a single station (n = 160) and 45.4% for patients with positive lymph nodes at multiple stations (n = 89) (log-rank test; p < 0.001). Five-year cumulative incidences of recurrence were equivalent between patients who received adjuvant chemotherapy and patients who did not (45.9 vs. 55.1%; Gray's test; p = 0.366). Distant recurrence was the most frequent mode of recurrence in both groups (70.8 and 67.3%).

CONCLUSION

The locations and the number of stations of the positive lymph nodes were identified as prognostic factors in patients with pN1 NSCLC. The primary mode of recurrence was distant recurrence irrespective of postoperative adjuvant chemotherapy.

Prognostic relevance of regional lymph-node distribution in patients with N1-positive non-small cell lung cancer: A retrospective single-center analysis

OBJECTIVE

Lymph node (LN) metastases predict survival in patients with non-small cell lung cancer (NSCLC) treated with curative surgery. Nevertheless, prognostic differences within the same nodal (N) status have been reported. Consequently, the International Association for the Study of Lung Cancer (IASLC) proposed to stratify patients with limited nodal disease (pN1) from low (pN1a) to high (pN1b) nodal tumor burden. This study aimed to validate the IASLC proposal in a large single-center surgical cohort of patients with pN1 NSCLC.

MATERIAL AND METHODS

Data from 317 patients with pN1 NSCLC treated between January 2012 and December 2016, were retrospectively analyzed. Associations between distribution of LN metastases and survival were analyzed for different classification models-toward nodal extension (pN1a: one station involved; pN1b: multiple stations involved) and toward location (pN1 in the hilar [LN#10/11] or peripheral zone [LN#12-14]).

RESULTS

Tumor-specific survival (TSS) in the entire pN1 cohort was 67.1% at five years. Five-year TSS rates for pN1a and pN1b patients were comparable (67.6% vs. 66.5%, p = 0.623). Significant survival differences from pN1a to pN1b were observed only in patients with adenocarcinoma histology and completed adjuvant chemotherapy (5-year TSS: pN1a, 80.4% vs. pN1b, 49.6%; p = 0.005). TSS for LN metastases in the hilar zone/peripheral zone or in both zones was 68.2% and 59.9%, respectively (p = 0.068). In multivariate analysis, adjuvant chemotherapy, squamous cell histology, and nodal disease limited to one zone nodal disease were identified as independent beneficial prognostic factors (p < 0.05).

CONCLUSION

pN1 in only one region (hilar or lobar) was associated with better outcome than metastatic affection of both regions after surgery and adjuvant therapy. A stratification towards single (pN1a) and multiple (pN1b) N1-metastases was found of prognostic relevance only in adenocarcinoma. Prospective multicenter analysis of prognostic subgroups in N1 NSCLC is required to evaluate its clinical impact for consideration in future TNM classification.

New perspective to evaluate N1 staging: The peripheral lymph node metastasis status of non-small cell lung cancer

Background

Lymph node (LN) metastasis status is the decision‐making basis for the surgical procedure and adjuvant therapy modalities. Fewer studies have previously focused on LN metastasis in N1 station, especially on peripheral lymph node (PLN) metastasis in N1 station. This study aimed to reveal the metastasis status of PLN of non‐small cell lung cancer (NSCLC), and investigate its effects on N staging.

Methods

We retrospectively evaluated a consecutive series of patients who underwent curative resection for histologically confirmed N1 NSCLC. Propensity score matching (PSM) was used to analyze the effects of PLN on N staging.

Results

A total of 105 patients with confirmed pathological N1 (pN1) stage NSCLC with solitary nodule and without neoadjuvant therapy were enrolled into the study: 55 patients had intraperipheral LN metastasis (IPLNM), and 50 patients had extra‐peripheral LN metastasis (EPLNM). Before PSM analysis, type of location (P = 0.002), surgical procedure (P = 0.008), number of positive LNs (P = 0.029), number of LNs removed (P = 0.010), lobe of lung cancer (P = 0.031), and vascular invasion (P = 0.049) showed significant differences between the two groups. After PSM analysis, statistically there were differences in type of location (P = 0.034), number of positive LNs (P = 0.008) and vascular invasion (P = 0.049) between them.

Conclusion

PLN metastasis was a quite common pattern of LN metastasis in N1 station of NSCLC. IPLNM occurred more frequently in central NSCLC and NSCLC with vascular invasion, and thoracotomy was likely to secure more accurate PLN staging. Clinicians should pay great attention to PLN dissection. Follow‐up data will be needed in order to detect the prognosis of IPLNM patients.

Prognostic impact of bulky swollen lymph nodes in cN1 non-small cell lung cancer patients

OBJECTIVE

The aim of this study was to analyze clinicopathological backgrounds and prognosis of clinical N1 non-small cell lung cancer and clarify the difference between bulky and non-bulky cN1 diseases.

METHODS

We reviewed 110 patients with completely resected cN1 non-small cell lung cancer and examined the prognostic impact of lymph node size. We classified the swollen lymph nodes into two groups based on their size on chest computed tomography: short-axis diameter ≥20 mm (=bulky group) or <20 mm (=non-bulky group).

RESULTS

The bulky group consisted of 10 patients, and the non-bulky group comprised 100 patients. There was no significant difference in the upstaging rate to pathological N2 between the bulky and non-bulky groups (31% vs. 30%; P = 0.63). The 5-year recurrence-free survival rate and 5-year overall survival rate of both groups did not differ significantly (P = 0.36, P = 0.30, respectively). Our results suggested the possibility that the size of the swollen lymph nodes had no impact on the prognosis in cN1 non-small cell lung cancer patients. In comparison of surgical procedure, pneumonectomy was performed in the bulky group more frequently than the non-bulky group (70% vs. 19%; P < 0.01).

CONCLUSIONS

Bulky cN1 disease was not different from non-bulky disease in the prognosis and the upstaging rate to pN2. Curative resection should be indicated to resectable bulky cN1 disease as with non-bulky disease, with careful pre-operative evaluation and preparation considering the possibility of pneumonectomy.

Prognostic value of metastatic N1 lymph node ratio and angiolymphatic invasion in patients with pathologic stage IIA non-small cell lung cancer

With regard to pathologic stage IIA (pIIA) non-small cell lung cancer (NSCLC), there is a paucity of literature evaluating the risk factors for disease-free survival (DFS) and overall survival (OS). The aim of this study was to identify the prognostic factors of DFS and OS in patients with NSCLC pIIA.We performed a retrospective review of 98 stage II patients (7th edition of the American Joint Committee on Cancer) who underwent lung resection from January 2005 to February 2011. Of these, 23 patients were excluded for this study because of loss of follow-up or different substage, and 75 patients with pIIA were included for further univariate and multivariate analysis. Risk factors for DFS and OS were analyzed, including age, gender, smoking history, operation method, histology, differential grade, visceral pleural invasion, angiolymphatic invasion, and metastatic N1 lymph node ratio (LNR).Of the 75 patients with pIIA NSCLC who were examined, 29 were female and 46 were male, with a mean age of 61.8 years (range: 34-83 years). The average tumor size was 3.188 cm (range: 1.10-6.0 cm). Under univariate analysis, angiolymphatic invasion and metastatic N1 LNR were risk factors for DFS (P = 0.011, P = 0.007). Under multivariate analysis, angiolymphatic invasion and metastatic N1 LNR were all independent risk factors for DFS, while adjuvant chemotherapy and higher metastatic N1 LNR were independent prognostic factors for OS.For patients with pIIA, higher metastatic N1 LNR and angiolymphatic invasion were related to poor DFS. In addition to DFS, higher metastatic N1 LNR was also a poor prognostic factor for OS rates and adjuvant therapy effectiveness. Clinical physicians should devise different postsurgical follow-up programs depending on these factors, especially for patients with high risk.

Prognostic significance of the extent of lymph node involvement in stage II-N1 non-small cell lung cancer

BACKGROUND

The non-small cell lung cancer (NSCLC) staging system (published in 2009 in the seventh edition of the cancer staging manuals of the Union for International Cancer Control and American Joint Commission on Cancer) did not include any changes to current N descriptors for NSCLC. However, the prognostic significance of the extent of lymph node (LN) involvement (including the LN zones involved [hilar/interlobar or peripheral], cancer-involved LN ratios [LNRs], and the number of involved LNs) remains unknown. The aim of this report is to evaluate the extent of LN involvement and other prognostic factors in predicting outcome after definitive surgery among Chinese patients with stage II-N1 NSCLC.

METHODS

We retrospectively reviewed the clinicopathologic characteristics of 206 patients with stage II (T1a-T2bN1M0) NSCLC who had undergone complete surgical resection at Shanghai Chest Hospital from June 1999 to June 2009. Overall survival (OS) and disease-free survival (DFS) were compared using Kaplan-Meier statistical analysis. Stratified and Cox regression analyses were used to evaluate the relationship between the LN involvement and survival.

RESULTS

Peripheral zone LN involvement, cancer-involved LNR, smaller tumor size, and squamous cell carcinoma were shown to be statistically significant indicators of higher OS and DFS by univariate analyses. Visceral pleural involvement was also shown to share a statistically significant relationship with DFS by univariate analyses. Multivariate analyses showed that tumor size and zone of LN involvement were significant predictors of OS.

CONCLUSIONS

Zone of N1 LN, LN ratios, and tumor size were found to provide independent prognostic information in patients with stage II NSCLC. This information may be used to stratify patients into groups by risk for recurrence.

Differential prognostic significance of extralobar and intralobar nodal metastases in patients with surgically resected stage II non-small cell lung cancer

OBJECTIVES

We sought to determine the prognostic significance of extralobar nodal metastases versus intralobar nodal metastases in patients with lung cancer and pathologic stage N1 disease.

METHODS

A retrospective review of a prospectively maintained lung resection database identified 230 patients with pathologic stage II, N1 non-small cell lung cancer from 1997 to 2011. The surgical pathology reports were reviewed to identify the involved N1 stations. The outcome variables included recurrence and death. Univariate and multivariate analyses were performed using the R statistical software package.

RESULTS

A total of 122 patients had extralobar nodal metastases (level 10 or 11); 108 patients were identified with intralobar nodal disease (levels 12-14). The median follow-up was 111 months. The baseline characteristics were similar in both groups. No significant differences were noted in the surgical approach, anatomic resections performed, or adjuvant therapy rates between the 2 groups. Overall, 80 patients developed recurrence during follow-up: 33 (30%) of 108 in the intralobar and 47 (38%) of 122 in the extralobar cohort. The median overall survival was 46.9 months for the intralobar cohort and 24.4 months for the extralobar cohort (P < .001). In a multivariate Cox proportional hazard model that included the presence of extralobar nodal disease, age, tumor size, tumor histologic type, and number of positive lymph nodes, extralobar nodal disease independently predicted both recurrence-free and overall survival (hazard ratio, 1.96; 95% confidence interval, 1.36-2.81; P = .001).

CONCLUSIONS

In patients who underwent surgical resection for stage II non-small cell lung cancer, the presence of extralobar nodal metastases at level 10 or 11 predicted significantly poorer outcomes than did nodal metastases at stations 12 to 14. This finding has prognostic importance and implications for adjuvant therapy and surveillance strategies for patients within the heterogeneous stage II (N1) category.

[Indications for surgery in non-small cell lung cancer with lymph node invasion]

Surgery is indicated for N1 non-small cell lung cancer and performed, with good results in some patients, when N2 disease is not diagnosed preoperatively "minimal N2". Following the publication of the "EORTC 08941" and "Intergroup 0139" trials, it remains debatable for patients with proven N2 disease. Good prognostic factors before treatment or post-induction favour surgery, which seems superior to radiochemotherapy if the operative risk is low (lobectomies, and some pneumonectomies). N3 status is a contraindication to surgery, except in some rare cases with a strong response to induction treatment.

Validation of the lymph node ratio as a prognostic factor in patients with N1 nonsmall cell lung cancer

BACKGROUND

The number of positive lymph nodes (LNs) has been proposed as a prognostic indicator in N1 nonsmall cell lung cancer (NSCLC). However, the number of positive LNs is confounded by the number of LNs resected during surgery. The lymph node ratio (LNR) (the ratio of the number of positive LNs divided by the number of LNs resected) can circumvent this limitation. The prognostic significance of the LNR has been demonstrated in elderly patients with NSCLC. The objective of the current study was to evaluate whether a higher LNR is a marker of worse survival in patients with NSCLC aged ≤65 years who have N1 disease.

METHODS

The Surveillance, Epidemiology, and End Results database was used to identify 4004 patients who underwent resection for N1 NSCLC. Patients were classified into 3 groups according to LNR (≤0.15, 0.16-0.5, and >0.5). Associations of the LNR with lung cancer-specific and overall mortality were evaluated using the Kaplan-Meier method. Stratified and Cox regression analyses were used to assess correlations between the LNR and survival after adjusting for other prognostic factors.

RESULTS

Unadjusted analysis indicated that a higher LNR was associated with worse lung cancer-specific survival (P < .0001) and overall survival (P < .0001). Stratified and multivariate analyses also indicated that the LNR was an independent predictor of survival after controlling for potential confounders.

CONCLUSIONS

The current results confirmed that the LNR is an independent prognostic factor for survival in patients with N1 NSCLC. This information may be used to identify patients who are at greater risk of cancer recurrence.

N1 non-small-cell lung cancer. A 20-year surgical experience

N1 non-small-cell lung cancer has heterogeneous prognosis in relation to node descriptors. There is no agreement on the ideal type of resection. A new classification of N1 descriptors was proposed in the 7th edition of the TNM staging system. A retrospective study was conducted on 384 patients with T1-T3N1 non-small-cell lung cancer who underwent complete pulmonary resection. The prognostic role of N1 descriptors according to the current and new staging systems and type of resection was investigated. The 5-year survival rate was 46%. Involvement of hilar node stations, multiple stations, and multiple nodes were poor prognostic factors (5-year survival, 33%, 21%, and 30%, respectively), as well as involvement of the hilar zone and multiple zones (5-year survival, 27% and 23%, respectively). Pneumonectomy showed significantly better survival rates compared to lobectomy or bilobectomy (5-year survival, 60% vs. 29%). Multivariate analysis showed that the number of N1 zones and type of resection were independent prognostic factors. Patients with hilar nodal, multiple-level, or multiple-zone involvement had poor prognosis. Standard lobectomy remains the procedure of choice, but in cases of fixed nodes in the hilar zone, sleeve resection or even pneumonectomy should be considered.