Lobe-specific extent of systematic lymph node dissection for non-small cell lung carcinomas according to a retrospective study of metastasis and prognosis

Assessment of non-lobe-specific lymph node metastasis in clinical stage IA non-small cell lung cancer

BACKGROUND

The rationality of selective mediastinal lymph node dissection based on lobe-specific metastasis is still controversial. The correlation of lymph node metastasis in lobe-specific lymphatic drainage regions (LSDRs) and non-LSDRs has not been widely reported. The purpose of this study was to investigate the variables affecting nodal metastasis in non-LSDRs and to further evaluate the rationality of selective lymphadenectomy in clinical stage IA non-small cell lung cancer (NSCLC) patients.

METHODS

The clinicopathological information of 316 patients with clinical stage IA NSCLC who underwent lobectomy with systematic lymph node dissection between June 2014 and June 2018 was retrospectively collected for analysis.

RESULTS

The overall lymph node metastasis rate was 19.3%. For 35 patients with positive LSDR lymph nodes, the non-LSDR lymph node metastasis rate was 31.4%. Only one patient (0.4%) among 281 patients with negative LSDR lymph nodes had nodal spread in non-LSDRs. Univariate analysis identified that solid consistency, worse differentiation, and positive status in LSDRs were unfavorable predictive variables of lymph node metastasis in non-LSDRs. Multivariate analysis showed that nodal metastasis in LSDRs was the only independent predictor of nodal involvement in non-LSDRs (P < 0.001).

CONCLUSION

For patients with clinical stage IA NSCLC, non-LSDR lymph node metastasis mainly depends on the involvement of the LSDR lymph node. Our observations may indicate the potential implications for the reasonable management of lymphadenectomy in stage IA NSCLC patients.

Prognostic Impact of the Number of Metastatic Lymph Nodes on the Eighth Edition of the TNM Classification of NSCLC

INTRODUCTION

Current nodal staging of NSCLC is defined only by anatomical location of lymph nodes (LNs). The aim of this study is to investigate prognostic impacts of the number of metastatic LNs by stratifying the present N classification.

METHODS

We analyzed 1989 patients with NSCLC who underwent complete resection by lobectomy or pneumonectomy involving dissection of the hilar and mediastinal LNs from 2003 to 2012. We classified patients according to the number of metastatic nodes and stations and their current category of metastatic LNs. We analyzed the overall survival in each group and assessed the survival impact of the combination of them.

RESULTS

In the multivariate analyses of all patients, pathological N1 (pN1) (reference [ref.] pN2) and single-node metastasis (ref. multiple-node) were independent prognostic factors whereas single-station metastasis (ref. multiple-station) was not. In the respective multivariate analyses of pN1 and pN2 disease, multiple-node metastasis (ref. single-node) was an independent prognostic factor in pN1 disease (hazard ratio: 1.41, p = 0.04), but not in pN2 disease. Investigation for other boundaries of a number of metastatic LNs of three or more (ref. one to two), four or more (ref. one to three), and five or more (ref. one to four) found that all of them were independent prognostic factors in both pN1 and pN2 diseases.

CONCLUSIONS

The number of metastatic LNs had a strong impact on survival in addition to the current pN classification. To clarify its prognostic impact, further study is needed in other datasets including patients treated by nonsurgical modalities.

Predictors of lymph node metastasis and possible selective lymph node dissection in clinical stage IA non-small cell lung cancer

Background

The pathologic stages of lymph nodes usually differ from preoperatively predicted in lung cancers and it is difficult to predict the metastasis of lymph nodes for the patients diagnosed as clinical stage IA non-small cell lung cancers (NSCLC). This study aimed to investigate the patterns of lymph node metastasis and the risk factors predicting lymph node metastasis in the patients with clinical stage IA NSCLCs.

Methods

All patients diagnosed as clinical stage IA NSCLC from July 2013 to June 2017 in our center were retrospectively reviewed, and a total number of 1,543 patients who underwent anatomical lobectomy with systematic lymph node dissection were enrolled in this study. Multivariate logistic regression analysis was performed to identify the risk factors predicting lymph node metastasis, and Fisher's exact test was used to confirm the lymph node spread mode according to the locations of primary tumors.

Results

Totally, lymph node metastases presented in 131 patients (8.5%) in this series. Sixty-three patients presented N1 diseases, 17 patients showed only skipped N2 diseases, and 51 patients had simultaneous N1 and N2 positive lymph nodes. No lymph node metastasis was found in the patients with pure ground grass opacity (GGO). When patients were arbitrarily divided into six groups by the longest tumor diameter of ≤0.5, 0.6-1, 1.1-1.5, 1.6-2.0, 2.1-2.5, 2.6-3 cm, the lymph node metastasis rates of each group were 0% (0/20), 1.5% (4/264), 4.7% (20/429), 8.6% (29/336), 13.1% (38/290), 19.6% (40/204), respectively. When the patients with pure GGO were excluded, the lymph node metastasis rates in the patients with partial or total solid tumors were 0% (0/10), 2.4% (4/164), 6.6% (20/303), 11.7% (29/249), 16.0% (38/238) and 23.1% (40/173). The cut off value showed by receiver operating characteristic (ROC) curve for tumor size was 1.95 cm, and the area under the curve (AUC) was measured as 0.681 (P<0.001, 95% CI: 0.630-0.726). Multivariate logistic regression analysis indicated that male patients [odds ratio (OR) =3.34, P=0.012], smoking history (OR =14.12, P<0.001), solid components (OR =3.34, P=0.01), large tumor size (OR =1.9, P<0.001), poor differentiation (OR =2.25, P=0.013), lymphovascular invasion (OR =58.45, P<0.001), visceral pleural invasion (OR =48.37, P<0.001) were significantly associated with lymph node metastasis in clinical stage IA NSCLC. The rate of non-lobe specific lymph node metastasis was 15.8-40.0% when any of the lobe specific lymph nodes was positive, while it was only 0-2.2% when all lobe specific lymph nodes were negative.

Conclusions

Tumor size, solid components, poor differentiation, lymphovascular invasion, visceral pleural invasion and smoking history were significant factors predicting lymph node metastasis of clinical stage IA NSCLC. Patients with negative lobe-specific lymph node have very low risk of metastasis to the non-lobe specific lymph nodes. Lobe-specific lymph node dissection may become an alternative lymph node dissection mode for clinical stage IA NSCLC, especially for tumors ≤2 cm.

Selective versus systematic lymph node dissection (other than sampling) for clinical N2-negative non-small cell lung cancer: a meta-analysis of observational studies

Background

The proper extent of lymph node dissection is still controversial. Hence, we compared the clinical efficacy between two strategies of lymph node dissection [selective lymph node dissection (SLND) and systematic lymph node dissection (LND)] for clinical N2-negative non-small cell lung cancer (NSCLC) patients.

Methods

After searching five databases, six cohort studies were eligible for this meta-analysis and the primary endpoint was overall survival (OS). In order to provide a comprehensive perspective, we estimated some perioperative outcomes as well. Either fixed effect or random effects model were properly selected to evaluate the data according to the heterogeneity of included studies.

Results

A total of 7,333 patients with clinical N2-negative NSCLC patients were analyzed for OS. The pooled results demonstrated that LND did not improve survival in OS [hazard ratio (HR) =1.05, 95% confidence interval (CI): 0.82-1.34, P=0.69] compared with SLND. In accordance with OS, there is no significant difference in DFS between LND and SLND (HR =0.98, 95% CI: 0.78-1.23, P=0.87). Moreover, SLND could significantly reduce the operative time [mean difference (MD) =-21.45, 95% CI: -29.53 to -13.36, P<0.001] and blood loss (MD =-28.88, 95% CI: -44.38 to -13.39, P<0.001). Both postoperative morbidity and recurrence showed no significant between two groups.

Conclusions

SLND is an alternative to LND for clinical N2-negative NSCLC patients, which may even provide clinical benefits. However, more randomized controlled trials (RCTs) are expected to determine whether SLND is valid and practical to become a standard procedure of surgical treatment for early-stage NSCLC patients.

Can lobe-specific lymph node dissection be an alternative to systematic lymph node dissection in treating early-stage non-small cell lung cancer: a comprehensive systematic review and meta-analysis?

Background

Whether lobe-specific lymph node dissection (L-SLND) could serve as an alternative to systematic lymph node dissection (SLND) in treating early-stage non-small cell lung cancer (NSCLC) remains unclear. Therefore, we conducted this comprehensive meta-analysis to compare the effect of L-SLND with that of SLND in treating early-stage NSCLC.

Methods

A systematic literature search in PubMed and Embase was conducted to identify relevant studies up to 30 November 2017. Data including 5-year overall survival (OS) and disease-free survival (DFS) rates, recurrence rates, and morbidity rate were extracted and analysed.

Results

A total of six studies [one randomized controlled trial (RCT) and five retrospective cohort studies] consisting of 2,037 patients with early-stage NSCLC were included for analysis. Meta-analysis showed that there was no significant difference of 5-year OS [81.7% and 79.5%, respectively; risk ratio (RR) =1.021; 95% confidence interval (CI), 0.977-1.068; P=0.352] and DFS (76.4% and 69.9%, respectively; RR =1.061; 95% CI, 0.999-1.128; P=0.054) between patients treated with L-SLND and those with SLND. Moreover, there was also no significant difference of total recurrence rates (24.3% and 25.8%, respectively; RR =0.892; 95% CI, 0.759-1.048; P=0.166) and loco-regional recurrence rates (7.9% and 9.3%, respectively; RR =0.851; 95% CI, 0.623-1.162; P=0.310) between patients treated with L-SLND and those with SLND. However, patients treated with L-SLND yielded a significant lower morbidity rate than those treated with SLND (10.2% and 13.5%, respectively; RR =0.681; 95% CI, =0.521-0.888; P=0.005).

Conclusions

L-SLND yielded a significantly lower risk of morbidity compared to SLND without compromising long-term oncologic outcomes based on available studies with relatively poor quality. L-SLND may serve as an alternative to SLND in treating early-stage NSCLC. Further well-conducted RCTs, however, are badly needed to confirm and update our conclusions.

[The Argument and Consensus of Lymphadenectomy on Lung Cancer Surgery]

淋巴结转移是肺癌的重要转移途径，淋巴结清扫术已成为肺癌的标准术式，同时也决定着肺癌的分期、预后及治疗策略。在临床实践中肺癌淋巴结的清扫方式各有不同，从选择性的淋巴结采样到扩大的淋巴结清扫，目前各种清扫方式存在着很大的争议，本文就目前的纵隔淋巴结清扫方式的共识及争议进行综述，为今后开展多中心临床研究提供参考。

Tumor histology predicts mediastinal nodal status and may be used to guide limited lymphadenectomy in patients with clinical stage I non-small cell lung cancer

OBJECTIVE

Methods to minimize surgical trauma from mediastinal lymphadenectomy in patients with early-stage lung cancer are still immature. This study aimed to identify predictors of negative pathologic N2, which may be used to select patients for limited mediastinal lymphadenectomy.

METHODS

Clinicopathologic features of 1430 patients with resected clinical stage I non-small cell lung cancer and complete mediastinal lymphadenectomy were retrospectively analyzed for variables associated with negative N2 nodal metastasis (2008-2015). Overall and recurrence-free survival in patients after complete or limited mediastinal lymphadenectomy were assessed via Kaplan-Meier survival analysis and log-rank testing. The accuracy of frozen section diagnosis for predicting final pathology was retrospectively assessed in 126 randomly selected patients after the surgery.

RESULTS

Multivariable analysis revealed that tumor size ≤2 cm, negative pN1, lymphovascular invasion, and lepidic adenocarcinoma were associated with negative mediastinal nodal metastasis. Notably, none of the patients with histology of adenocarcinoma in situ, minimally invasive adenocarcinoma, or lepidic pattern-predominant adenocarcinoma on final pathology had pN2 disease, and the 5-year overall and recurrence free-survival of these patients (99.3% and 99.3%, respectively) was not different from those after limited mediastinal lymphadenectomy (98.7% and 100%, P = .582 and .511, respectively). If these subtypes were classified together as the low-risk group, the concordance rate between frozen section and final pathology diagnosis was 88.9% in the retrospective test cohort.

CONCLUSIONS

Tumor histology may predict negative mediastinal metastasis in patients with early-stage lung cancer. Future prospective studies are merited to validate the feasibility of using frozen section to select patients for limited mediastinal lymphadenectomy.

Incidence of occult pN2 disease following resection and mediastinal lymph node dissection in clinical stage I lung cancer patients

Objectives

Early clinical stage (T1 and T2) non-small cell lung cancer (NSCLC) is commonly treated with anatomic lung resection and lymph node sampling or dissection. The aims of this study were to evaluate the incidence and the distribution of occult N2 disease according to tumour location and the short- and long-term outcomes.

Methods

We performed a retrospective review of patients with clinical stage I NSCLC who underwent anatomic lung resection and lymphadenectomy. Mediastinal lymphadenectomy (ML) was defined as resection of at least 2 mediastinal stations, always including station 7 lymph nodes. Patients who had a lobe-specific lymphadenectomy were excluded.

Results

One thousand six hundred and sixty-seven consecutive patients met inclusion criteria and were included. Overall, 9% (146/1667) of the patients had occult pN2 disease. At multivariable analysis, adenocarcinoma histology and vascular invasion were independently associated with greater risk of occult pN2 disease. In left and right upper lobe tumours, station 7 nodes were involved in 5 and 13% of pN2 positive cases, respectively. Station 5 and station 2/4 nodes were involved in 29 and 18% of left and right lower lobe pN2 tumours, respectively. There was no postoperative mortality, and postoperative morbidity was 28%. The median overall survival was 77.4 months. N0 patients had a median overall survival of 83.7 months vs 48.0 months and 37.9 months in N1 and N2 populations, respectively ( P  < 0.001).

Conclusions

Sixteen percent of pN2 patients had mediastinal lymph node metastasis beyond the lobe-specific lymphatic drainage. We recommend a complete lymphadenectomy be performed, even in clinical stage I NSCLC.

Selective lymph node dissection in early-stage non-small cell lung cancer

Lymph node dissection is a vital part of surgical treatment in early-stage non-small cell lung cancer (NSCLC). Removal of metastatic lymph nodes while preservation of intact lymph nodes are equally important. For hospitalized early-stage patients with limited lymph node metastasis, the operation treatment should be made according to some rules such as lobe-specific lymph node drainage pattern. In order to prevent unnecessary surgical trauma in early-stage patients, a minimally invasive approach with selective lymph node excision is preferred for more clinical benefits. This review summarizes the existing findings on lobe-specific lymph node drainage pattern and we hope to provide guidance for selective lymph node dissection (SLND). Furthermore, we include information on histologic views, a tumor marker and protocols of SLND, with hope to inspire creative research and clinical trials in this field.

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

Background

Pathologic N2 non-small-cell lung cancer (NSCLC) was demonstrated with poor survival among literature. In this study, we retrospectively reviewed patients with pathologic N2 NSCLC and received anatomic resection (i.e. lobectomy) for further relapse risk factor analysis. The aim of this study is to identify the clinicopathologic factors related to relapse among resectable N2 NSCLC patients and to help clinicians in developing individualized follow up program and treatment plan.

Method

From January 2005 to July 2012, 90 diagnosed pathologic N2 NSCLC patients were enrolled into this study. We retrospectively reviewed medical records, image studies, and pathology reports to collect the patient clinico-pathologic factors.

Result

We identified that patients with visceral pleural invasion (p = 0.001) and skip metastases along mediastinal lymph node (p = 0.01) had a significant relationship to distant and disseminated metastases. Patients who had 2 or more risk factors for relapse demonstrated poor disease free survival than those who had less than 2 risk factors (p = 0.02). The number of involved metastatic area were significantly influential to the period of time-to-progression. The duration of time-to-progression was correlated with square of number of involved metastatic areas. (Pearson correlation coefficient = −0.29; p = 0.036).

Conclusion

Relapse risk factors of resectable pathologic N2 NSCLC patient after anatomic resection were visceral pleural invasion, skip mediastinal lymph node involvement, and the receipt of neoadjuvant therapy. The duration of time-to-progression was correlated with square of number of involved metastatic areas.

Subcarinal Lymph Nodes Should be Dissected in All Lobectomies for Non-Small Cell Lung Cancer-Regardless of Primary Tumor Location

BACKGROUND

Mediastinal staging is of paramount importance for planning of treatment in non-small cell lung cancer (NSCLC). Single institution reports recently claimed that subcarinal lymph node dissection during resection of upper lobe NSCLC could be spared. We used a complete national lung cancer registry to investigate patterns of unsuspected mediastinal lymph node involvement after lobectomy.

METHODS

During an 11-year period (2004 to 2014) 5,577 consecutive patients who underwent operations for NSCLC were investigated for unsuspected mediastinal lymph node involvement (N2 disease) discovered at final histopathology. The analysis excluded patients with clinical N2 disease. We used a national registry to extract information for each patient about tumor location, histopathology, clinical and pathologic TNM stage, preoperative imaging modalities, and type of invasive mediastinal staging.

RESULTS

Mediastinal lymph node dissection was performed in 5,577 patients during the operation, and unsuspected N2 disease was discovered in 612 (11.0%), and 193 (3.5%) had subcarinal metastasis. Subcarinal N2 disease was significantly more common in patients with lower-lobe or middle-lobe cancers compared with upper-lobe cancers (5.8% vs 1.6%, p < 0.01). Preoperative invasive mediastinal staging was performed in 73.4% (4,097 of 5,577) of all patients and significantly more frequently in patients who eventually had N2 disease (87.3% [534 of 612], p < 0.01) as well subcarinal N2 disease (89.6% [173 of 193], p < 0.01).

CONCLUSIONS

Subcarinal lymph node metastases were common despite frequent use of preoperative invasive mediastinal staging in lower-lobe, middle-lobe, and upper-lobe NSCLC. Subcarinal lymph nodes should be dissected or sampled routinely during operations for NSCLC to avoid understaging-regardless of preoperative invasive mediastinal staging and tumor location.

Metachronous Lung Cancer: Clinical Characteristics and Effects of Surgical Treatment

The occurrence of a second lung tumor after surgical removal of lung cancer usually indicates a lung cancer metastasis, but sometimes a new lesion proves to be a new primary lung cancer, i.e., metachronous lung cancer. The goal of the present study was to conduct a clinical evaluation of patients with metachronous lung cancer and lung cancer metastasis, and to compare the early and distant outcomes of surgical treatment in both cancer types. There were 26 age-matched patients with lung cancer metastases and 23 patients with metachronous lung cancers, who underwent a second lung cancer resection. We evaluated the histological type of a resected cancer, the extent of thoracosurgery, the frequency of early postoperative complications, and the probability of 5-year survival after the second operation. The findings were that metachronous lung cancer was adenocarcinoma in 52% of patients, with a different histopathological pattern from that of the primary lung cancer in 74% of patients. In both cancer groups, mechanical resections were the most common surgery type (76% of all cases), with anatomical resections such as segmentectomy, lobectomy, or pneumectomy being much rarer conducted. The incidence of early postoperative complications in metachronous lung cancer and lung cancer metastasis (30% vs. 31%, respectively) and the probability of 5-year survival after resection of either cancer tumor (60.7% vs. 50.9%, respectively) were comparable. In conclusion, patients undergoing primary lung cancer surgery require a long-term follow-up due to the risk of metastatic or metachronous lung cancer. The likelihood of metachronous lung cancer and pulmonary lung cancer metastases, the incidence of postoperative complications, and the probability of 5-year survival after resection of metachronous lung cancer or lung cancer metastasis are similar.

Subxiphoid single-port video-assisted thoracoscopic surgery

Background

We report the feasibility and safety of chest surgery through the subxiphoid single port approach based on our preliminary experience.

Methods

From December 2013 till January 2016, 39 patients underwent 40 thoracoscopic surgeries via a 3- to 4-cm subxiphoid single incision. A sternal lifter was applied for better entrance and working angle. A zero-degree deflectable scope was preferred. The technique for anatomic resection was similar to that in the traditional single-port approach. Patient characteristics and demographic data were analyzed.

Results

There were 29 females and 10 males, with a median age of 56 years. Indication for surgery included 24 patients with primary lung cancer, eight with lung metastases, two with benign lung lesions, one with bilateral pneumothorax, and five with mediastinal tumors. Surgeries included lobectomy in 21, segmentectomy in five, wedge resection in nine, and mediastinal surgery in five patients. There was no surgical mortality. Complications (10%, 4 in 40) included postoperative bleeding in one patient, chylothorax in one patient, and transient arrhythmia in the early learning curve in two patients.

Conclusions

Our results indicated that subxiphoid single-incision thoracoscopic pulmonary resection could be performed safely but under careful patient selection with modification of instruments. Moreover, having a previous single-port incision experience was crucial. Major limitations of this approach included more frequently encountered instrument fighting; interference of left-side procedure related to heartbeat and radical mediastinal lymph node (LN) dissection; and the ability to handle complex conditions, such as anthracotic LNs, diffuse adhesion, and major bleeding.

[Advances in Lymph Node Metastasis and the Modes of Lymph Node Dissection in Early Stage Non-small Cell Lung Caner]

目前，肺癌已是全球范围内发病率及死亡率最高的恶性肿瘤，非小细胞肺癌（non-small cell lung cancer, NSCLC）约占肺癌80%。手术治疗在早期NSCLC治疗中占主导地位，而淋巴结分期及手术中清扫程度直接影响着患者术后生活质量及患者的预后。解剖性肺叶切除加系统性淋巴结清扫一直以来被认为是NSCLC的标准手术方式，但对早期NSCLC患者纵隔淋巴结清扫程度问题上一直存在较大争议，精确评估区域淋巴结的转移及淋巴结清扫的程度是影响患者围手术期并发症和预后的重要因素。对于早期肺癌行肺叶特异性或选择性淋巴结清扫已逐渐为国内外学者接受，并可能成为临床Ⅰ期NSCLC患者标准淋巴结清扫方式。

Therapeutic value of lymph node dissection for right middle lobe non-small-cell lung cancer

BACKGROUND

Superior mediastinal and #11i lymph node (LN) metastases are adverse prognostic factors in patients with middle lobe lung cancer. We aimed to clarify the benefit of thorough lymphadenectomy by LN station or zone in middle lobe non-small-cell lung cancer (NSCLC).

METHODS

Among 295 patients who underwent pulmonary resection and thorough lymphadenectomy for primary right middle lobe (RML) NSCLC at two institutions, we enrolled 68 patients (33 men, 35 women) and retrospectively studied their data. We divided each N1 location (i.e., #10, #11s and #11i) into N1(-)N2(+) and N1(+)N2(+) and divided the #12m location into N1(+)N2(-), N1(-)N2(+) and N1(+)N2(+).

RESULTS

Interlobar node involvement was rare in pN1 NSCLC when compared with that in other N1 nodes. Lymph node dissection (LND) was beneficial when the hilar zone (HZ)/interlobar zone (IZ) LNs were located at the intermediate point of the upper zones (UZs) and subcarinal zones (SCZs), with the therapeutic benefit at the SCZ being 2.8-fold higher than that at the UZ and 9.7-fold higher than that at the lower zone (LZ). Furthermore, LND evidently had greater therapeutic value for the SCZ than the UZ, which was compatible with skip N2 metastases.

CONCLUSIONS

For middle lobe NSCLC, mediastinal LND should be considered a priority in the SCZ than in the UZ. Moreover, the HZ/IZ is central to unfavourable prognoses in patients with pN2 middle lobe NSCLC.

Boundary between N1 and N2 Lymph Node Descriptors in the Subcarinal Zone in Lower Lobe Lung Cancer: A Brief Report

INTRODUCTION

In the International Association for the Study of Lung Cancer (IASLC) lymph node (LN) map, some LNs in the subcarinal space defined as #10 (N1) in the Naruke map were changed to #7 (N2). We aimed to validate the boundary between N1 and N2 in the subcarinal zone.

METHODS

We reviewed the records of 399 consecutive patients who had undergone complete resection for lower lobe non-small cell lung cancer. Involved lymph node stations were classified as N1 by both maps (N1 group), N1 by the Naruke map but reclassified as N2 by the IASLC map (#10 [subcarinal] group), and N2 by both maps (N2 group). The survival rates among these groups were compared using Kaplan-Meier and log-rank analyses.

RESULTS

LNs were classified as N0, N1, and N2 in 268, 67, and 64 patients, respectively, on the IASLC map and as N1 and N2 in 82 and 49 patients, respectively, on the Naruke map. The 5-year disease-free survival rates were 81.7% for N0, 50.9% for N1, 33.3% for the #10 (subcarinal) group, and 24.4% for N2. The rates of the N1 and #10 (subcarinal) groups were significantly different (p = 0.027), but those of the N2 and #10 (subcarinal) groups were not (p = 0.78). On multivariate analysis, metastatic disease in the LNs of #10 in the subcarinal space was an independent prognostic factor for patients classified as N1 on the Naruke map (hazard ratio = 2.47, 95% confidence interval: 1.17-4.85, p = 0.019).

CONCLUSION

All lymph nodes in the subcarinal space should be defined as #7 (N2) for prognosis.

A lobe-specific lymphadenectomy protocol for solitary pulmonary nodules in non-small cell lung cancer

BACKGROUND

We want to establish a lobe-specific mediastinal lymphadenectomy protocol for solitary pulmonary nodules (SPNs) in non-small cell lung cancer (NSCLC).

METHODS

We retrospectively analyzed 401 patients with pathological diagnoses of NSCLC who underwent lobectomy, bilobectomy, or pneumonectomy with systematic lymphadenectomy from March 2004 to June 2011 in our hospital. All of the patients enrolled had a SPN preoperatively. Information about the primary tumor location, lymph node metastasis, and other baseline data were collected. Stepwise logistic regression was used to identify the key factors indicating non-regional mediastinal lymph node metastases (NRM).

RESULTS

Of the primary tumors, 117, 39, 74, 104, and 67 were in the right upper lung (RUL), right middle lung (RML), right lower lung (RLL), left upper lung (LUL), and left lower lung (LLL), respectively. Stepwise regression showed that #2,4, #10,11, and #10,11 as well as #7 was the key lymph node station for RUL, LUL, and lower lobes: #2,4 [odds ratio (OR)=28.000, 95% confidence interval (CI): 2.917-268.790, P=0.004] for RUL, #10,11 (OR=31.667, 95% CI: 2.502-400.833, P=0.008) for LUL, #10,11 (OR=19.540, 95% CI: 4.217-90.541, P<0.001) and #7 (OR=7.395, 95% CI: 1.586-34.484, P=0.011) for lower lobes, respectively. Patients with tumors >2 cm rarely had NRM without primary regional mediastinal involvement.

CONCLUSIONS

With rigid consideration, a lobe-specific lymphadenectomy is feasible in practice. This protocol can be used when the lobe-specific key nodes are negative in intraoperative frozen sections, especially for NSCLC diagnosed as SPN <2 cm preoperatively.

Dosimetric evaluation of the feasibility of stereotactic body radiotherapy for primary lung cancer with lobe-specific selective elective nodal irradiation

More than 10% of all patients treated with stereotactic body radiotherapy (SBRT) for primary lung cancer develop regional lymph node recurrence. We evaluated the dosimetric feasibility of SBRT with lobe-specific selective elective nodal irradiation (ENI) on dose-volume histograms. A total of 21 patients were treated with SBRT for Stage I primary lung cancer between January 2010 and June 2012 at our institution. The extents of lobe-specific selective ENI fields were determined with reference to prior surgical reports. The ENI fields included lymph node stations (LNS) 3 + 4 + 11 for the right upper lobe tumors, LNS 7 + 11 for the right middle or lower lobe tumors, LNS 5 + 11 for the left upper lobe tumors, and LNS 7 + 11 for the left lower lobe tumors. A composite plan was generated by combining the ENI plan and the SBRT plan and recalculating for biologically equivalent doses of 2 Gy per fraction, using a linear quadratic model. The V20 of the lung, D(1cm3) of the spinal cord, D(1cm3) and D(10cm3) of the esophagus and D(10cm3) of the tracheobronchial wall were evaluated. Of the 21 patients, nine patients (43%) could not fulfill the dose constraints. In all these patients, the distance between the planning target volume (PTV) of ENI (PTVeni) and the PTV of SBRT (PTVsrt) was ≤2.0 cm. Of the three patients who developed regional metastasis, two patients had isolated lymph node failure, and the lymph node metastasis was included within the ENI field. When the distance between the PTVeni and PTVsrt is >2.0 cm, SBRT with selective ENI may therefore dosimetrically feasible.

Outcomes of initial surgery in patients with clinical N2 non-small cell lung cancer who met 4 specific criteria

PURPOSE

The role of surgery for patients with non-small cell lung cancer (NSCLC) with clinical mediastinal lymph node metastasis (N2) remains controversial. We specified 4 criteria for performing initial surgery in these patients (single-station N2, non-bulky N2, N2 with regional mode of spread, and N2 without N1) and examined the outcomes to validate the treatment options.

METHODS

Between September 2002 and December 2010, of 1290 patients who underwent complete resection for NSCLC, 808 patients underwent initial standard resection, including 779 patients with cN0-1 and 29 with cN2. We compared the outcomes, and evaluated patients with cN2-pN2.

RESULTS

The median follow-up was 45.5 months (3-119 months). Seventy (9.0 %) and 24 (82.8 %) patients had p-N2 in the cN0-1 and cN2 groups, respectively (p < 0.0001). The 5-year disease-free survival (DFS) rates in the cN0-1 and cN2 groups were 73.3 and 50.6 %, respectively (p = 0.0053), and the 5-year overall survival (OS) rates were 81.3 and 71.1 %, respectively (p = 0.051). The 5-year DFS and OS of patients with cN2-pN2 were 52.5 and 72.6 %, respectively.

CONCLUSIONS

Patients with clinical N2 disease based on our criteria represent a highly specific group with a favorable prognosis. Resection should therefore be the initial treatment for these patients.

Lymph Node Metastases and Prognosis in Left Upper Division Non-Small Cell Lung Cancers: The Impact of Interlobar Lymph Node Metastasis

Background

Left upper division segmentectomy is one of the major pulmonary procedures; however, it is sometimes difficult to completely dissect interlobar lymph nodes. We attempted to clarify the prognostic importance of hilar and mediastinal nodes, especially of interlobar lymph nodes, in patients with primary non-small cell lung cancer (NSCLC) located in the left upper division.

Methods

We retrospectively studied patients with primary left upper lobe NSCLC undergoing surgical pulmonary resection (at least lobectomy) with radical lymphadenectomy. The representative evaluation of therapeutic value from the lymph node dissection was determined using Sasako’s method. This analysis was calculated by multiplying the frequency of metastasis to the station and the 5-year survival rate of the patients with metastasis to the station.

Results

We enrolled 417 patients (237 men, 180 women). Tumors were located in the lingular lobe and at the upper division of left upper lobe in 69 and 348 patients, respectively. The pathological nodal statuses were pN0 in 263 patients, pN1 in 70 patients, and pN2 in 84 patients. Lymph nodes #11 and #7 were significantly correlated with differences in node involvement in patients with left upper lobe NSCLC. Among those with left upper division NSCLC, the 5-year overall survival in pN1 was 31.5% for #10, 39.3% for #11, and 50.4% for #12U. The involvement of node #11 was 1.89-fold higher in the anterior segment than that in the apicoposterior segment. The therapeutic index of estimated benefit from lymph node dissection for #11 was 3.38, #4L was 1.93, and the aortopulmonary window was 4.86 in primary left upper division NSCLC.

Conclusions

Interlobar node involvement is not rare in left upper division NSCLC, occurring in >20% cases. Furthermore, dissection of interlobar nodes was found to be beneficial in patients with left upper division NSCLC.

Current methods of staging and restaging of the mediastinal nodes in non-small-cell lung cancer

To analyze the current methods of primary staging and repeated staging (restaging) of the mediastinal nodes in non-small-cell lung cancer (NSCLC), all methods currently used for staging of NSCLC are analyzed. These methods include imaging techniques [computer tomography (CT), positron emission tomography (PET) combined with CT (PET/CT)], endoscopic/ultrasound techniques (endobronchial ultrasound/transbronchial needle aspiration) and endoscopic ultrasound/fine needle aspiration and surgical techniques [standard cervical mediastinoscopy, video-assisted mediastinoscopy, extended mediastinoscopy, video-assisted mediastinoscopic lymphadenectomy, transcervical extended mediastinal lymphadenectomy, anterior mediastinotomy (Chamberlain procedure) and video-assisted thoracic surgery]. The diagnostic yield of Chest CT is regarded insufficient for both, primary staging and restaging. The PET/CT became a standard imaging technique preceding curative surgery of radical chemo-radiotherapy. The issue of intraoperative staging is also described. Finally, the author’s proposed algorithm of staging, both for primary staging and restaging after neoadjuvant therapy is presented. Detailed staging of NSCLC enables selection of patients with early stage disease for curative surgical/multimodality treatment and helps to avoid unnecessary surgery in advanced disease.

Risk factors for recurrence after complete resection of pathological stage N2 non-small cell lung cancer

Background

Tumor recurrence is the most common cause of treatment failure, especially after complete resection of pathological stage N2 non-small cell lung cancer (NSCLC). In this study, we investigated the clinicopathological characteristics in order to identify independent risk factors for postoperative recurrence.

Methods

Between January 2001 and December 2013, 96 patients who underwent surgical resection for pathological N2 NSCLC were retrospectively reviewed. Recurrence-free survival (RFS) was calculated by the Kaplan-Meier method to explore risk factors, while the Cox proportional hazard model was used to assess independent predictors.

Results

The median and five-year RFS rates were 15 months and 27.4%, respectively. Univariate analysis showed a significantly poorer prognosis for non-regional N2 metastasis, more than three metastatic N2 lymph nodes, multiple N2 station, and multiple N2 zone involvement. Multivariate analysis demonstrated that non-regional N2 metastasis (hazard ratio [HR] 1.857, 95% confidence interval [CI] 1.061–3.249, P = 0.030) and more than three metastatic N2 lymph nodes (HR 2.555, 95% CI 1.164–5.606, P = 0.019) were independent risk factors for RFS. Additionally, the incidence of non-regional N2 metastasis was higher in patients with a primary tumor in the left lower (57.1%) or right lower lobe (48.1%), followed by left upper (31.8%), right middle (14.3%) and right upper lobe (7.7%).

Conclusion

The combination of the distribution and number of metastatic N2 lymph nodes provides a more accurate prediction for N2 NSCLC regarding recurrence. Non-regional N2 metastasis could occur with a primary tumor in any lobe, but occurs more frequently in the lower lobe.

Prognosis and segment-specific nodal spread of primary lung cancer in the right lower lobe

Background

Although lobe-specific nodal spread of primary lung cancer has been recently described, segment-specific nodal spread remains unclear. We investigated the frequency of hailer and mediastinal lymph node involvement and survival in patients with tumors located in the superior segment (SS) and basal segment (BS) in the right lower lobe.

Methods

Two hundred and sixty-three patients with primary lung cancer originating in the right lower lobe underwent lobectomy with systematic mediastinal lymph node dissection. Patients were categorized into two groups: SS (n = 114) or BS (n = 149).

Results

Frequencies of metastasis to station 11s and 11i were significantly higher in the SS (P < 0.0001) and BS groups (P = 0.022), respectively. Both the SS and BS groups showed a high frequency of subcarinal mediastinal zone (station 7) metastasis (96.9% and 90.6%, respectively; P = 0.271). The frequencies of superior mediastinal zone (station 2R and 4R) metastasis were 37.5% in the SS and 35.8% in the BS group (P = 0.878). In patients with pN2 disease, three-year disease-free survival was significantly shorter in the SS (22.6%) than the BS group (42.1%; P = 0.020). In the BS group, the independent predictive factors of a poor or good prognosis were metastasis to station 11i or skip metastasis, respectively; however, we did not detect an independent prognostic factor in the SS group. In the right lower lung lobe, there was no segment-specific nodal spread.

Conclusion

When segmentectomy is undertaken, mediastinal lymph node dissection should be performed in proportion to lobectomy.

Cyclooxygenase-2 expression is a prognostic biomarker for non-small cell lung cancer patients treated with adjuvant platinum-based chemotherapy

Background

Adjuvant chemotherapy after the resection of stage IB-IIIA non-small cell lung cancer (NSCLC) is now the standard of care based on large-scale phase III trials and a meta-analysis. However, chemotherapy has plateaued in terms of its efficacy, and the search for treatment prediction biomarkers is imperative for the further identification of treatable subgroups. Therefore, we investigated the significance of cyclooxygenase-2 (Cox-2) expression and the applicability of a Cox-2 inhibitor in patients who had received adjuvant chemotherapy.

Methods

We conducted a retrospective review of data from 97 patients who had received adjuvant chemotherapy. The adjuvant chemotherapy consisted of an oral tegafur agent (OT) or platinum-based chemotherapy (PB). The criteria for regimen selection were based on a discussion among the cancer board and enrollment in a clinical trial. Immunohistochemical staining (IHC) for Cox-2 was performed, and the correlation between Cox-2 expression and disease-free survival (DFS) was evaluated.

Results

IHC showed that 56 cases (57.7%) were positive for Cox-2. The rate of Cox-2 expression was similar for the PB and OT groups. Among the patients who received PB, the DFS of the patients with Cox-2 expression was significantly poorer than that of the patients without Cox-2 expression (P = 0.017), but there was no significant difference among the patients who received OT (P = 0.617). In a multivariate analysis, Cox-2 expression and lymph node metastasis were independent predictors of DFS among patients who received PB.

Conclusions

Cox-2 expression was a powerful predictor of DFS among patients who received PB as an adjuvant chemotherapy. Further study investigating the use of a Cox-2 inhibitor for adjuvant chemotherapy is needed.

Classifications of n2 non-small-cell lung cancer based on the number and rate of metastatic mediastinal lymph nodes

BACKGROUND

Subdivisions of N2 non-small-cell lung cancer (NSCLC) cases based on metastatic status of mediastinal and non-mediastinal lymph nodes have been proposed. This study aimed to evaluate N2 disease classification by mediastinal lymph nodes alone.

PATIENTS AND METHODS

We reviewed 187 patients with NSCLC pN1-N2 who were surgically treated to evaluate the proposed classifications: number, rate, nodal zone of metastatic lymph nodes. We evaluated N2 disease classification based on mediastinal lymph nodes alone in 136 pN2 cases.

RESULTS

The number (1-2, 3-5, and 6 ≤) or rate (15%≥, 15%< to 40%>, and 40%≤) classification based on all metastatic lymph nodes was validated by the log-rank test and Cox proportional hazards model. After reclassification by number or rate of metastatic mediastinal lymph nodes alone, a significant difference was maintained among all groups except between the 3-5 and 6 ≤ groups. The 5-year survival rates of the 1-2, 3-5, and 6 ≤ groups were 63.4%, 32.4%, and 18.2%, respectively (1-2 vs. 3-5, P = .015; 3-5 vs. 6 ≤, P = .134). With rate classification, the 5-year survival rates of the 15%≥, 15%-40% (15%< to 40%>), and 40%≤ groups were 56.0%, 27.3%, and 5.04%, respectively (15%≥ vs. 15%-40%, P = .011; 15-40% vs. 40%≤, P = .011). The Spearman's rank correlation coefficient showed a highly significant correlation of metastatic status between mediastinal lymph nodes and all lymph nodes (both P < .001).

CONCLUSION

Classification by number and rate of mediastinal lymph nodes alone enabled subdivision of N2 NSCLC cases. Metastatic status of mediastinal lymph nodes reflects that of all lymph nodes and is prognostic indicators.

Staging lymph node metastases from lung cancer in the mediastinum

BACKGROUND

The presence of tumor metastases in the mediastinum is one of the most important elements in determining the optimal treatment strategy in patients with non-small cell lung cancer. This review is aimed at examining the current strategies for investigating lymph node metastases corresponding to an "N2" classification delineated by The International Staging Committee of the International Association for the Study of Lung Cancer (IASLC).

METHODS

Extensive review of the existing scientific literature related to the investigation of mediastinal lymph node metastases was undertaken in order to summarize and report current best practices.

CONCLUSIONS

N2 disease is very heterogeneous requiring multiple modalities for thorough investigation. New research is now focusing on better identifying, defining, and classifying lymph node metastases in the mediastinum. Molecular staging and sub-classifying mediastinal lymph node metastases are being actively researched in order to provide better prognostic value and to optimize treatment strategies. Non-invasive imaging, such as PET/CT and minimally invasive techniques such as endobronchial and endoscopic ultrasound guided biopsy, are now the lead investigative methods in evaluating the mediastinum for metastatic presence.

Is the lymphatic drainage of lung cancer lobe-specific? A surgical appraisal

OBJECTIVES

Nowadays, early-stage lung cancers are more frequently encountered. Selective lymph node (LN) dissection based on lobe-specific lymphatic pathway has been proposed. Our aim was to study nodal involvement according to tumour location.

METHODS

We reviewed 1779 lobectomized patients and analysed their pathological characteristics according to tumour location: Group 1 (G1), right upper lobe; Group 2 (G2), right middle lobe; Group 3 (G3), right lower lobe; Group 4 (G4), left upper division; Group 5 (G5), lingula; Group 6 (G6), left lower lobe. The pN status was recorded for each group to analyse the lymphatic spread of non-small-cell lung cancer (NSCLC) according to tumour location.

RESULTS

The numbers and proportions of lobectomies in each group were 613 patients in G1 (59.2%), 64 in G2 (6.4%), 359 in G3 (34.6%), 404 in G4 (54.3%), 54 in G5 (7.3%) and 286 in G6 (38.4%). The rates of pN2 involvement were similar, whatever the group was, even when deciphering single- and multistation diseases. on the right side, single-station N2 disease was mainly found in the superior mediastinum (SM) for G1 (95%), and in the inferior for G3 (90%). On the left side, single-station N2 was mainly found in the SM in G4 (94%), and the inferior in G6 (48%). Whatever the side, in case of two-station involvement, both mediastina were concerned in 40% (in G4) to 81% of the case (in G3). Long-term survival rates were different in skip metastasis, single- and multistation involvement, but not between lobes.

CONCLUSIONS

Tumour location is not a predictor of nodal metastasis pattern. In surgical treatment of NSCLC, complete systematic mediastinal LN dissection remains the only acceptable procedure from an oncological point of view.

The Prognosis According to Patterns of Mediastinal Lymph Node Metastasis in Pathologic Stage IIIA/N2 Non-Small Cell Lung Cancer

Background

The aim of this study is to evaluate prognostic factors for survival in pathologic stage IIIA/N2 non-small-cell lung cancer (NSCLC), to identify the prognostic significance of the metastatic patterns of mediastinal lymph nodes (MLNs) relating to survival and to recurrence and metastasis.

Methods

A total of 129 patients who underwent radical resection for pathologic stage IIIA-N2 NSCLC from July 1998 to April 2011 were retrospectively reviewed. The end points of this study were rates of loco-regional recurrence and distant metastasis, and survival.

Results

The overall 5-year survival rate was 47.4%. A univariate analysis showed that age, pathologic T stage, and adjuvant chemotherapy were significant prognostic factors, while in multivariate analysis, pathologic T stage and adjuvant chemotherapy were significant prognostic factors. The metastasis rate was higher in patients with multistation N2 involvement and with more than 3 positive MLNs. Further, non-regional MLN metastasis was associated with a higher loco-regional recurrence rate.

Conclusion

Pathologic T stage and adjuvant chemotherapy were independent prognostic factors for long-term survival in pathologic stage IIIA/N2 NSCLC. The recurrence and the metastasis rate were affected by the metastatic patterns of MLNs. These results may be helpful for planning postoperative therapeutic strategies and predicting outcomes.

Lobe-specific mediastinal nodal dissection is sufficient during lobectomy by video-assisted thoracic surgery or thoracotomy for early-stage lung cancer

BACKGROUND

Lobectomy with complete mediastinal lymphadenectomy is considered standard for patients with early-stage non-small cell lung cancer (NSCLC). However, the benefits of complete lymphadenectomy are unproven. There is evidence suggesting a predictable pattern of mediastinal nodal drainage. This study analyzed the frequency and pattern of mediastinal nodal disease and its impact on outcome in patients with early-stage NSCLC.

METHODS

Patients with clinical N0/N1 NSCLC staged with CT scans and PET scans were identified. Disease involvement of resected nodal stations was recorded. Patterns of recurrence in patients who underwent lobectomy with complete mediastinal systematic lymph node sampling (SLNS) were compared with those who underwent lobe-specific mediastinal SLNS.

RESULTS

From July 2004 to April 2011, 370 patients were identified. Complete SLNS was performed in 282 patients. Fifteen patients (5.3%) in the group with complete SLNS were found to have N2 disease after pathologic evaluation. Patients with left-sided tumors were more likely to have pathologic N2 disease than were patients with right-sided tumors (P = .03). Only one patient (0.36%) had positive N2 disease in the distal mediastinum while skipping lobe-specific mediastinal nodes. In addition, patients with complete SLNS had a rate of recurrence similar to that of the group that had lobe-specific mediastinal evaluation (20.6% vs 18.2%, P = .68).

CONCLUSIONS

Mediastinal N2 metastases follow predictable lobe-specific patterns in patients with negative preoperative CT scans and PET scans. Lobe-specific N2 nodal evaluation results in a recurrence rate similar to that of complete mediastinal evaluation. Lobe-specific mediastinal nodal evaluation appears acceptable in patients with early-stage NSCLC.

Is the rate of pneumonectomy higher in right middle lobe lung cancer than in other right-sided locations?

BACKGROUND

Historically, right middle lobe (RML) non-small cell lung cancer (NSCLC) has been reported to be associated with a higher rate of pneumonectomy than other right-sided locations. Because this would discourage minimally invasive approaches in RML-NSCLC, we sought to update this assertion through the study of a large surgical series.

METHODS

Clinical records of patients who underwent operations for right-sided NSCLC in 2 French surgical centers were prospectively entered and retrospectively reviewed. Demographic and pathologic characteristics of RML NSCLC were compared with other right-sided NSCLC.

RESULTS

This study included 3,234 right-sided and 211 RML (6.5%) NSCLC patients. After exclusion of 14 patients who underwent exploratory thoracotomy, patients were a mean age of 61.5 years, most RML resections occurred in men (134 [72.8%]), and most were lobectomies (wedge, n=4; lobectomy, n=102; bilobectomy, n=22; pneumonectomy, n=56). Pathologic analysis revealed adenocarcinoma in 88 patients (47.8%) and squamous cell carcinoma in 80 (43.5%). pStaging was stage I in 86 patients (46.7%), II in 42 (22.8%), III in 47 (25.5%), and IV in 9 (4.9%). Superior and inferior mediastinal N2 were found in 45.4% and 54.6% of patients, respectively, when 1 station was involved. When compared with other right-sided NSCLC, RML was characterized by higher T status and higher rates of bilobectomy (10.9% vs 5.6%, p=0.0017) and pneumonectomy (30.3% vs 22.3%, p=0.0071) but similar 5-year survival (47.4%).

CONCLUSIONS

Compared with other right-sided NSCLC, RML location is associated with a higher albeit limited rate of pneumonectomy.