The IASLC Lung Cancer Staging Project: Proposals for the Revision of the N Descriptors in the Forthcoming Seventh Edition of the TNM Classification for Lung Cancer

New TNM classification: achievements and hurdles

The 7th edition of TNM for Lung Cancer represented a major advance from previous editions, in the process of revision, the size and breadth of the data base used, its international character, the intensity of the analysis and the critical nature of the internal and external validation undertaken before its launch in January 2010. This all came about by the involvement of the International Association for the Study of Lung Cancer (IASLC), which assumed the role previously performed by Dr. Mountain, of developing data-driven revisions for the Union for International Cancer Control (UICC) and the American Joint Committee on Cancer (AJCC). In taking on this task the IASLC made the global lung cancer community aware of the limitations of previous revisions and now stand accountable and subject to the same scrutiny. In this article we describe the achievements of the IASLC TNM and Prognostic Factors Committee, but also the short-comings of the 7th edition, as an essential step towards rectifying deficiencies and further improving the classification in future revisions.

Reappraisal of the role of postoperative radiation therapy in patients with pIIIa-N2 non-small cell lung cancer: A propensity score matching analysis

Background

Reappraisal of the role of postoperative radiotherapy in pN2 non-small cell lung cancer (NSCLC) patients according to N1 lymph node involvement.

Methods

A total of 218 pIIIa-N2 NSCLC patients who underwent complete surgical resection with systematic nodal dissections were enrolled. Propensity scores were used for matching N1 involvement. Overall survival (OS) and disease-free survival (DFS) were analyzed retrospectively.

Results

After matching, pN2b patients without N1 involvement (pN0N2b) exhibited better prognoses than those with N1 involvement (pN1N2b) (5-year OS: 37.5% vs. 7.1%, P = 0.008; 5-year DFS: 31.8% vs. 4.6%, P = 0.004). Similar results were not detected in pN2a disease (5-year OS: 37.8% vs. 31.0%, P = 0.517; 5-year DFS: 27.1% vs. 20.2%, P = 0.788). The five-year OS of patients who received no adjuvant therapy (22 pN2a cases, 7 pN0N2b, 5 pN1N2b), adjuvant chemotherapy alone (74 pN2a cases, 11 pN0N2b, 17 pN1N2b) or chemoradiotherapy (25 pN2a cases, 7 pN0N2b, 6 pN1N2b) were compared (pN2a: 31.3%, 37.0%, and 32.0%, P = 0.808; pN0N2b: 0.0%, 18.2%, and 71.4%, P = 0.108; pN1N2b: 0.0%, 0.0%, and 33.3%, P < 0.0001). The five-year DFS was also analyzed (pN2a: 31.6%, 24.0%, and 18.3%, P = 0.410; pN0N2b: 0.0%, 11.1%, and 57.1%, P = 0.192; pN1N2b: 0.0%, 0.0%, and 16.7%, P < 0.0001). Multivariate analysis revealed that the novel classification based on N1 involvement and pN2a/pN2b staging was an independent prognostic factor of OS and DFS.

Conclusion

N1 involvement significantly impacted the prognosis of pN2b NSCLC patients. The benefit of adjuvant therapy in pN2a and pN0N2b patients requires confirmation by further study.

The impact of positive nodal chain ratio on individualized multimodality therapy in non-small-cell lung cancer

This study aimed to analyze the prognostic significance of the positive nodal chain ratio (NCR) in non-small-cell lung cancer (NSCLC). A total of 208 pIIIa-N2 NSCLC patients who underwent complete surgical resections with a systematic nodal dissection were enrolled. The median values of NCR and the positive lymph node ratio (LNR) were used to grouping patients. The differences of overall survival (OS) and disease-free survival (DFS) between the different groups were compared. The median values of NCR and LNR were 0.31 and 0.45, respectively. The patients were separated into group A (NCR ≤0.45 and LNR ≤0.31; 91 cases), group B (NCR ≤0.45 and LNR >0.31 or NCR >0.45 and LNR ≤0.31; 51 cases), and group C (NCR >0.45 and LNR >0.31; 66 cases) according to their combined LCR and LNR values. Groups A, B, and C exhibited significantly different prognoses (5-year OS: 43.7, 25.2, and 12.3 %, respectively, p < 0.0001; 5-year DFS: 30.4, 23.3, and 8.6 %, respectively, p < 0.0001). Multivariate analyses revealed that this novel grouping method based on the combination of NCR and LNR was an independent prognostic factor for 5-year OS and 5-year DFS in pIIIa-N2 NSCLC. In group C, patients who received no postoperative treatment, adjuvant chemotherapy alone, or chemoradiotherapy exhibited different 5-year OS rates (0.0, 11.6, and 37.5 %, respectively, p = 0.003) and 5-year DFS rates (0.0, 7.5, and 25.0 %, respectively, p = 0.009). Therefore, postoperative chemoradiotherapy may significantly improve the prognosis of patients displaying NCR >0.45 and LNR >0.31. NCR combined with LNR may be more effective to guide individualized multimodality therapy including postoperative chemoradiotherapy for pIIIa-N2 NSCLC.

Is lower zone mediastinal nodal dissection always mandatory for lung cancer in the lower lobe?

PURPOSE

Dissection of the lower zone mediastinal nodes is mandatory during systematic nodal dissection for lung cancer. However, the significance of lower zone lymph node metastasis (LZM) in lung cancer remains unclear. Therefore, we aimed to identify the predictive factors for LZM in patients with lower lobe lung cancer.

METHODS

A retrospective study was conducted on 257 patients with lower lobe lung cancer, in whom pulmonary resection and mediastinal nodal dissection were performed between 2009 and 2013. The radiological factors on thin-section computed tomography scans (TSCT) and several conventional clinical factors were evaluated as possible predictors of LZM.

RESULTS

Twenty (7.8 %) patients exhibited LZM. The majority of the tumors were especially located in segment 10 (50 %). All patients showed a solid appearance on TSCT. In a univariate analysis, the tumor location, a solid appearance and the clinical T factor significantly predicted LZM (p = 0.011, 0.005, 0.018). Furthermore, based on a multivariate analysis, the tumor location in segment 10 significantly predicted LZM in patients with lower lobe solid lung cancer (p = 0.031).

CONCLUSION

The appropriate surgical strategy for lower zone lymph node dissection should be selected based on the tumor location and the findings of TSCT, due to the high frequency of LZM (19.6 %), especially in patients with pure solid lung cancer in segment 10.

Prognostic Factors for Surgically Resected N2 Non-small Cell Lung Cancer

PURPOSE

Non-small cell lung cancers (NSCLCs) with pathologically documented ipsilateral mediastinal lymph node (LN) metastases (pN2) are a broad spectrum of diseases. We retrospectively analyzed prognostic factors for cases of pN2 NSCLC treated by surgical resection.

METHODS

Clinicopathological data were reviewed for consecutive 121 patients who underwent anatomical pulmonary resection with mediastinal LN sampling or dissection for pN2 NSCLC over a 15-year period.

RESULTS

The 5-year survival rate for all patients was 29.9%. Clinical N status, curability, surgical procedure and adjuvant chemotherapy were favorable prognostic factors in univariate analysis, with 5-year survival rates of 35.0% for cN0/1 vs. 17.7% for cN2/3 cases; 33.1% for R0 vs. 14.7% for R1/2 resection; 31.5% for lobectomy vs. 25.0% for bilobectomy and 15.6% for pneumonectomy; and 72.7% with adjuvant chemotherapy vs. 23.8% without adjuvant chemotherapy. Survival did not differ significantly based on gender, age, smoking status, clinical T status, tumor location, histology, skip metastasis, subcarinal LN metastasis, or number of involved N2 levels. In multivariate analysis, adjuvant chemotherapy, R0 resection, and lobectomy emerged as independent favorable prognostic factors.

CONCLUSION

Complete resection using lobectomy and adjuvant chemotherapy are favorable prognostic factors in cases of pN2 NSCLC.

Optimization of lymph node dissection with VATS right upper lobectomy

Video-assisted thoracoscopic lobectomy (VATSL) has developed rapidly. As per the requirements of tumor staging and oncotherapy, the technique of VATS mediastinal lymph node dissection plays an important role. With our experience, lymph node dissection can be performed very well on the condition that surgical process and skills be optimized.

Analysis of stage and clinical/prognostic factors for lung cancer from SEER registries: AJCC staging and collaborative stage data collection system

BACKGROUND

The American Joint Committee on Cancer (AJCC) 7th edition introduced major changes in the staging of lung cancer, including the tumor (T), node (N), metastasis (M)-TNM-system and new stage/prognostic site-specific factors (SSFs), collected under the Collaborative Stage Version 2 (CSv2) Data Collection System. The intent was to improve the stage precision that could guide treatment options and ultimately lead to better survival. This report examines stage trends, the change in stage distributions from the AJCC 6th to the 7th edition, and findings of the prognostic SSFs for 2010 lung cancer cases.

METHODS

Data were from the November 2012 submission of 18 Surveillance, Epidemiology, and End Results (SEER) Program population-based registries. A total of 344,797 cases of lung cancer, diagnosed in 2004-2010, were analyzed.

RESULTS

The percentages of small tumors and early-stage lung cancer cases increased from 2004 to 2010. The AJCC 7th edition, implemented for 2010 diagnosis year, subclassified tumor size and reclassified multiple tumor nodules, pleural effusions, and involvement of tumors in the contralateral lung, resulting in a slight decrease in stage IB and stage IIIB and a small increase in stage IIA and stage IV. Overall about 80% of cases remained the same stage group in the AJCC 6th and 7th editions. About 21% of lung cancer patients had separate tumor nodules in the ipsilateral (same) lung, and 23% of the surgically resected patients had visceral pleural invasion, both adverse prognostic factors.

CONCLUSIONS

It is feasible for high-quality population-based registries such as the SEER Program to collect more refined staging and prognostic SSFs that allows better categorization of lung cancer patients with different clinical outcomes and to assess their survival.

[Is there a place for surgical management in stage IIIA N2 non-small cell lung cancer?]

INTRODUCTION

Non-small cell lung cancer (NSCLC) remains a major health problem, with a 5-year overall survival of 25%. Surgical management of stage IIIA NSCLC is still controversial. We conduct a systematic analysis of the different management strategies for stage IIIA-N2 NSCLC.

METHODS

We analyzed randomized control trials published between January 1990 to December 2013, comparing induction chemotherapy followed by surgery vs. surgery alone, and those comparing induction chemo or radiotherapy followed by surgery vs. induction chemotherapy followed by radiotherapy for stage IIIA-N2 NSCLC.

RESULTS

A 16% significant increase in overall survival was found in favor of induction chemotherapy followed by surgery vs. surgery alone. However, there was no significant difference in overall survival between induction chemo- or radiotherapy followed by surgery and induction chemotherapy followed by radiotherapy.

CONCLUSION

Current scientific data do not permit the exclusion of surgery as an option in the management of stage IIIA-N2 NSCLC.

Extended resections of non-small cell lung cancers invading the aorta, pulmonary artery, left atrium, or esophagus: can they be justified?

T4 tumors that invade the heart, great vessels, or esophagus comprise a heterogenous group of locally invasive lung cancers. Prognosis depends on nodal status; this relationship has been consistently demonstrated in many of the small series of extended resection. Current National Comprehensive Cancer Network guidelines do not recommend surgery for T4 extension with N2-3 disease (stage IIIB). However, biopsy-proven T4 N0-1 (stage IIIA) may be operable. Localized tumors with invasion of the aorta, pulmonary artery, left atrium, or esophagus represent a small subset of T4 disease. Acquiring sufficient randomized data to provide statistical proof of a survival advantage for patients undergoing extended resections for these neoplasms will likely never be possible.Therefore, we are left to critically analyze current documented experience to make clinical decisions on a case-by-case basis.It is clear that the operative morbidity and mortality of extended resections for locally advanced T4 tumors have significantly improved over time,yet the risks are still high. The indications for such procedures and the anticipated outcomes should be clearly weighed in terms of potential perioperative complications and expertise of the surgical team. Patients with T4 N0-1 have the best prognosis and with complete resection may have the potential for cure. The use of induction therapy and surgery for advanced T4 tumors may improve survival. Current data suggest that for tumors that invade the aorta, pulmonary artery,left atrium, or esophagus, resection should be considered in relation to multidisciplinary care.For properly selected patients receiving treatment at high volume, experienced centers, extended resections may be warranted.

Change of junctions between stations 10 and 4 in the new International Association for the Study of Lung Cancer Lymph Node Map: a validation study from a single, tertiary referral hospital experience

BACKGROUND

Some tumors previously staged as N2 disease, using the Mountain-Dresler/American Thoracic Society (MD-ATS) map are staged as N1 per the new International Association for the Study of Lung Cancer (IASLC) lymph node (LN) map. We aimed to evaluate the effectiveness of the IASLC LN map in stratifying prognosis in patients with non-small cell lung cancer (NSCLC) and LN metastasis in nodal stations 4 or 10.

METHODS

Of 2,086 patients undergoing curative surgical resection for NSCLC, we searched for patients who had LNs harboring cancer cells in nodal stations 10 or 4 (n = 531) and reclassified them into three different subgroups (N1 [N1 according to both the MD-ATS and IASLC maps], in-between [N2 according to the MD-ATS map but N1 by the IASLC map], and N2 [N2 according to both maps]) based on histopathologic results. We compared disease-free survival (DFS) among the three subgroups by using the Kaplan-Meier method and log-rank analysis.

RESULTS

Of 531 patients, 295 belonged to the N1 group, 66 patients belonged to in-between group, and 170 patients belonged to N2 group, according to the IASLC map. The cumulative DFS rates at 5 years for the N1, in-between, and N2 groups were 47%, 39%, and 29%, respectively. In multivariate analysis, LN ratio was identified as significant independent prognostic factor (hazard ratio, 2.877; 95% CI, 1.391-5.950; P = .004).

CONCLUSIONS

The changed definition between N1 and N2 diseases by the IASLC LN map works well, as expected, in stratifying patient prognosis. Positive LN ratio may be more valuable than the nodal stations involved in predicting patient survival in resectable NSCLC.

Current innovations in sentinel lymph node mapping for the staging and treatment of resectable lung cancer

Despite surgical resectability, early-stage lung cancer remains a challenge to cure. Survival outcomes are hindered by variable performance of adequate lymphadenectomy and the limitations of current pathologic nodal staging. Sentinel lymph node (SLN) mapping, a mainstay in the management of breast cancer and melanoma, permits targeted nodal sampling for efficient and accurate staging that can influence both intraoperative and adjuvant treatment decisions. Unfortunately, standard SLN identification techniques with blue dye and radiocolloid tracers have not been shown to be reproducible in lung cancer. In more recent years, intraoperative near-infrared image-guided lung SLN mapping has emerged as promising technology for the identification of the tumor-associated lymph nodes most likely to contain metastatic disease. Additionally, the clinical relevance of SLN mapping for lung cancer remains pressing, as the ability to identify micrometastatic disease in SLNs could facilitate trials to assess chemotherapeutic response and the clinical effect of occult nodal disease. This review outlines the status of lung cancer lymphatic mapping and techniques in development that may help close the gap between translational research in this field and routine clinical practice.

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.

Accuracy of positron emission tomography in identifying hilar (N1) lymph node involvement in non-small cell lung cancer: Implications for stereotactic body radiation therapy

PURPOSE

To assess the efficacy of preoperative positron emission tomography (PET) to stage the ipsilateral hilum in resected non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

All patients who underwent surgery for NSCLC between 1995 and 2008 were evaluated. Patients who underwent preoperative PET imaging at our institution and had hilar nodal sampling were included. Those whose primary tumors extended to the hilum or who received preoperative chemotherapy or radiation therapy were excluded. All PET studies were interpreted by an attending nuclear medicine radiologist and were scored as positive or negative in the hilum or peribronchial area based on visual analysis alone. A 2-sided Fisher exact test compared patient subgroups.

RESULTS

During the time interval, 1558 patients underwent surgery for NSCLC, of whom 484 were eligible for this analysis. The ipsilateral hilum was positive on preoperative PET in 107 patients. The median number of N1 lymph nodes sampled was 4 (range, 1-31). Positive ipsilateral N1 lymph nodes were identified pathologically in 91 patients (19%). Among the 91 patients with involved N1 lymph nodes, 40 were PET positive resulting in a sensitivity of 44%. Among 393 patients without pathologic involvement of hilar lymph nodes, 326 were PET negative resulting in a specificity of 83%. The positive predictive and negative predictive values were 37% and 86%, respectively.

CONCLUSIONS

Positron emission tomography appears to have limitations in staging the ipsilateral hilar lymph nodes. Invasive sampling is appropriate if treatment would differ based on the nodal status.

Survival analysis of patients with non-small cell lung cancer who underwent surgical resection following 4 lung cancer resection guidelines

Background

To compare survival of patients with non-small cell lung cancer (NSCLC) who underwent surgical resection and lymph node sampling based on guidelines proposed by the American College of Surgeons Oncology Group (ACOSOG), National Comprehensive Cancer Network (NCCN), the OSI Pharmaceutical RADIANT trial, and the International Association for the Study of Lung Cancer (IASLC).

Methods

Medical records of patients with NSCLC who underwent surgical resection from 2001 to 2008 at our hospital were reviewed. Staging was according to the 7^th edition of the AJCC TNM classification of lung cancer. Patients who received surgical resection following the IASLC, ACOSOG, RADIANT or NCCN resection criteria were identified.

Results

A total of 2,711 patients (1803 males, 908 females; mean age, 59.6 ± 9.6 years) were included. Multivariate Cox proportional hazards regression analysis indicated that increasing age, adenosquamous histology, and TNM stage II or III were associated with decreased overall survival (OS). Univariate analysis and log-rank test showed that surgical resection following the guidelines proposed by the IASLC, NCCN, ACOSOG, or RADIANT trial was associated with higher cumulative OS rates (relative to resection not following the guidelines). Multivariate analysis revealed that there was a significant improvement in OS only when IASLC resection guidelines (complete resection) were followed (hazard ratio = 0.84, 95% confidence interval 0.716 to 0.985, P = 0.032).

Conclusions

Surgical resection following the criteria proposed by IASLC, NCCN, ACOSOG, or the RADIANT trial was associated with a higher cumulative OS rate. However, significant improvement in OS only occurred when IASLC resection guidelines were followed.

Elevated serum C-reactive protein, carcinoembryonic antigen and N2 disease are poor prognostic indicators in non-small cell lung cancer

AIM

To assess the prognostic value of mediastinal lymph node metastases (N2 disease), carcinoembryonic antigen (CEA) levels and C-reactive protein (CRP) in non-small cell lung cancer (NSCLC), according to the 7th edition of the TNM classification.

METHODS

Newly diagnosed stage III-IV NSCLC were enrolled, including 75 patients with malignant pleural effusion. The relationship between serum CRP levels and other relevant variables such as sex, Eastern Cooperative Oncology Group status, smoking status, initial staging, N2 disease, serum albumin, white blood cell count, platelet count, CEA, comorbidity and pathology were analyzed. Univariate and multivariate analyses were performed to find prognostic markers using Cox's proportional hazards model.

RESULTS

Of the 127 patients enrolled, 55 (43%) had elevated CRP levels. There was a significant correlation between serum CRP level and platelet count (P = 0.011). Median overall survival (OS) in the normal CRP group was significantly longer than in the high CRP group (15.7 months vs 9.1 months, P = 0.013). Hypoalbuminemia (P = 0.047), higher CEA (P = 0.043) and N2 disease (P = 0.040) were additional prognostic factors on univariate analysis. On multivariate analysis an elevated CRP serum level (HR = 1.796; P = 0.005), higher CEA (HR = 1.563; P = 0.031) and N2 disease (HR = 1.723; P = 0.012) were independent prognostic factors for poor survival.

CONCLUSION

High levels of serum CRP and CEA, and N2 disease are independent prognostic indicators for the survival of patients with stage III-IV NSCLC.

The impact of a novel lung gross dissection protocol on intrapulmonary lymph node retrieval from lung cancer resection specimens

Although thorough pathologic nodal staging provides the greatest prognostic information in patients with potentially curable non-small cell lung cancer, N1 nodal metastasis is frequently missed. We tested the impact of corrective intervention with a novel pathology gross dissection protocol on intrapulmonary lymph node retrieval. This study is a retrospective review of consecutive lobectomy, or greater, lung resection specimens over a period of 15 months before and 15 months after training pathologist's assistants on the novel dissection protocol. One hundred forty one specimens were examined before and 121 specimens after introduction of the novel dissection protocol. The median number of intrapulmonary lymph nodes retrieved increased from 2 to 5 (P<.0001), and the 75th to 100th percentile range of detected intrapulmonary lymph node metastasis increased from 0 to 5 to 0 to 17 (P=.0003). In multivariate analysis, the extent of resection, examination period (preintervention or postintervention), and pathologic N1 (vs N0) status were most strongly associated with a higher number of intrapulmonary lymph nodes examined. A novel pathology dissection protocol is a feasible and effective means of improving the retrieval of intrapulmonary lymph nodes for examination. Further studies to enhance dissemination and implementation of this novel pathology dissection protocol are warranted.

Modern outcome and risk analysis of surgically resected occult N2 non-small cell lung cancer

BACKGROUND

This study was performed to assess the incidence, survival, and risk factors associated with unsuspected pathologic N2 disease in patients with resectable clinical N0-1 non-small cell lung cancer.

METHODS

Between January 2002 and December 2010, 1,821 patients with clinical N0-1 non-small cell lung cancer underwent pulmonary resection and mediastinal lymph node dissection. Clinical outcomes and risk factors for pathologic N2 disease were retrospectively analyzed for this cohort.

RESULTS

Unsuspected pathologic N2 disease was identified in 196 patients (10.8%). The most common type of resection was lobectomy (81.6%). Adjuvant therapy was administered in 177 patients (90.3%). The median follow-up time was 28 months (range, 1 to 101 months). N2 involvement was single-station in 121 (66.8%) and multiple-station in 65 (33.2%). The 5-year overall and disease-free survival rates were 56.1% and 35.0%, respectively. The 5-year survival rates of single-station and multiple-station N2 were 66.6% and 36.4%, respectively (p < 0.001). Adenocarcinoma, clinical N1, tumor size (>3 cm), and a right middle lobe tumor were identified as independent risk factors for unsuspected multiple-station N2 disease by multivariate analysis. Incidence of unsuspected multiple-station N2 disease in low-risk classes (aggregate score, 0 to ≤2) was only 5.5%.

CONCLUSIONS

The incidence of unsuspected N2 disease in our cohort was similar to that of previous reports. Survival outcomes were favorable for unsuspected single-station N2 disease but were poor for unsuspected multiple-station N2 disease. Clinical N0-1 non-small cell lung cancer patients with risk class of low score for unsuspected multiple-station N2 disease can be exempted from aggressive mediastinal staging.

Evaluation of the 7th edition of the TNM classification for lung cancer at a single institution

PURPOSE

To assess the utilities and drawbacks of the 7th edition of the TNM classification for lung cancer.

METHODS

Subjects included 1,469 patients who underwent pulmonary resection for primary non-small cell lung cancer. Survival characteristics were compared using the 6th and 7th editions of the staging system.

RESULTS

According to the 6th and 7th editions, respectively, the 5-year survival rates based on stages were as follows: pStage IA (81.0, 81.0 %), pStage IB (70.6, 72.0 %), pStage IIA (61.3, 59.7 %), pStage IIB (56.6, 47.2 %), pStage IIIA (43.4, 37.6 %), pStage IIIB (8.9, 14.9 %), and pStage IV (14.0, 8.0 %). According to the 6th edition, there was no significant difference between pStages IB and IIA (P = 0.268), or between pStages IIA and IIB (P = 0.622), or between pStages IIIB and IV (P = 0.737). According to the 7th edition, there were significant differences between each adjacent stage group, except between pStages IIIB and IV (P = 0.424). According to the 7th edition staging system, 5-year survival rates by T classification were as follows: pT1a, 81.6 %; pT1b, 75.9 %; pT2a, 60.1 %; pT2b, 44.7 %; pT3, 24.4 %; and pT4, 13.2 %; with significant differences between each adjacent pT classification. The 5-year survival rates by M classification were as follows: M0, 57.2 %, M1a, 9.1 %, M1b, 0 %, with a significant difference between M0 and M1a, but there was no significant difference between M1a and M1b.

CONCLUSION

The UICC 7th edition staging system is considered valid for non-small cell lung cancer patients and appears to be superior in defining different prognostic groups than the 6th edition.

Combined endobronchial and transesophageal approach of an ultrasound bronchoscope for mediastinal staging of lung cancer

Background

We evaluated the utility of a combined approach using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and transesophageal bronchoscopic ultrasound-guided fine-needle aspiration (EUS-FNA-B/E) for mediastinal staging of lung cancer.

Methods

An EBUS-TBNA database was analyzed retrospectively. EUS-FNA-B/E was performed after EBUS-TBNA when mediastinal lymph nodes were not accessible using EBUS-TBNA or when tissue sampling using EBUS-TBNA alone was inadequate.

Results

During the study period, 44 patients were enrolled. EBUS-TBNA and EUS-FNA-B/E were performed on 79 and 52 lymph nodes, respectively. The sensitivity, specificity, and accuracy of mediastinal N-staging using EBUS-TBNA alone were 79%, 100%, and 84%, respectively. The sensitivity, specificity, and accuracy of mediastinal N-staging using a combination of EBUS-TBNA and EUS-FNA-B/E were 100%, 100%, and 100%, respectively. Significant differences in sensitivity (P = 0.008) and accuracy (P = 0.004) of mediastinal N-staging were evident when EBUS-TBNA alone and the combined procedure were compared. The nodal stage shifted higher after use of the EUS-FNA-B/E procedure in six cases (13%). No serious complication associated with the procedures was noted.

Conclusions

Use of a combination of EBUS-TBNA and EUS-FNA-B/E can afford better sensitivity and accuracy of mediastinal N-staging compared with use of EBUS-TBNA alone. Such combined procedures should be considered for examination of lesions that are inaccessible or difficult to access by EBUS-TBNA.

Revised ESTS guidelines for preoperative mediastinal lymph node staging for non-small-cell lung cancer

Accurate preoperative staging and restaging of mediastinal lymph nodes in patients with potentially resectable non-small-cell lung cancer (NSCLC) is of paramount importance. In 2007, the European Society of Thoracic Surgeons (ESTS) published an algorithm on preoperative mediastinal staging integrating imaging, endoscopic and surgical techniques. In 2009, the International Association for the Study of Lung Cancer (IASLC) introduced a new lymph node map. Some changes in this map have an important impact on mediastinal staging. Moreover, more evidence of the different mediastinal staging technique has become available. Therefore, a revision of the ESTS guidelines was needed. In case of computed tomography (CT)-enlarged or positron emission tomography (PET)-positive mediastinal lymph nodes, tissue confirmation is indicated. Endosonography [endobronchial ultrasonography (EBUS)/esophageal ultrasonography (EUS)] with fine-needle aspiration (FNA) is the first choice (when available), since it is minimally invasive and has a high sensitivity to rule in mediastinal nodal disease. If negative, surgical staging with nodal dissection or biopsy is indicated. Video-assisted mediastinoscopy is preferred to mediastinoscopy. The combined use of endoscopic staging and surgical staging results in the highest accuracy. When there are no enlarged lymph nodes on CT and when there is no uptake in lymph nodes on PET or PET-CT, direct surgical resection with systematic nodal dissection is indicated for tumours ≤ 3 cm located in the outer third of the lung. In central tumours or N1 nodes, preoperative mediastinal staging is indicated. The choice between endoscopic staging with EBUS/EUS and FNA or video-assisted mediastinoscopy depends on local expertise to adhere to minimal requirements for staging. For tumours >3 cm, preoperative mediastinal staging is advised, mainly in adenocarcinoma with high standardized uptake value. For restaging, invasive techniques providing histological information are advisable. Both endoscopic techniques and surgical procedures are available, but their negative predictive value is lower compared with the results obtained in baseline staging. An integrated strategy using endoscopic staging techniques to prove mediastinal nodal disease and mediastinoscopy to assess nodal response after induction therapy needs further study.

Size and histologic characteristics of lymph node material retrieved from tissue discarded after routine pathologic examination of lung cancer resection specimens

Redissection of discarded lung resection specimens after routine pathology examination reveals missed lymph node metastasis. We sought to determine if size can be used to grossly select lymph nodes for microscopic examination. This is a prospective cohort study of lymph nodes retrieved from discarded lung resection specimens. The association between size and histologic characteristics of retrieved material was compared by the Wilcoxon-Mann-Whitney test. We retrieved 1094 grossly 'lymph node-like" tissue from 112 remnant lung resection specimens, of which 345 (32%) proved not to be lymph nodes and 71 (9%) of 749 lymph nodes had metastasis. Metastasis was present in discarded nodes in 26 (23%) of 112 patients. The non-lymph node tissue was significantly smaller than lymph nodes (P < .0001); lymph nodes with metastases were significantly larger than those without metastases (P < .0001). However, there was significant size overlap between the 3 types of grossly lymph node-like tissue. Thirty-two percent of nodes with metastasis were less than 1 cm; 15% of patients had at least 1 lymph node less than 1 cm with metastasis. The size difference between lymph nodes with and without metastasis is clinically unhelpful because of broad overlap. Size is insufficiently discriminatory and cannot be relied on to select materials for histologic examination. A third of grossly retrieved material was non-lymph node tissue. This probably occurs during routine pathologic examination and likely contributes to the low N1 lymph node count.

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.

[Lymphatic spread of lung cancer: anatomical lymph node chains unchained in zones]

Lung cancer is characterized by its lymphophilia. Its metastatic spread mainly occurs by tumor cells lymphatic drainage into the blood circulation. Initially, the lymph node TNM classification was based on clinical and therapeutic considerations, particularly concerning N2 involvement. The goals were to avoid futile exploratory thoracotomies without lung resection, to provide more accurate data from mediastinoscopy, and to take into account the radiation therapy fields. Since 1997, the international lymph node classification was more used to analyse the disparities within N1 and N2 groups. However, this attempt did not succeed in clarifying the lymphatic metastazing process, and was not progressing any more. Anatomy not being considered, it did not permit to grasp the anatomical and physiological significances of N2 and N3 involvement. In effect, this classification is now confined in zones and is lacking the anatomical and physiological descriptions that characterise the lymphatic pathways draining the lungs and their tumoral pathology. The stations proposed in numbers in cartographies should have gained in accuracy and in prognostic value if they had been expressed in their anatomical counterparts.

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.

Comparison of endobronchial ultrasound and/or endoesophageal ultrasound with transcervical extended mediastinal lymphadenectomy for staging and restaging of non-small-cell lung cancer

BACKGROUND

To compare the diagnostic yield of endobronchial ultrasound (EBUS) and/or endoesophageal ultrasound (EUS) with transcervical extended mediastinal lymphadenectomy (TEMLA) for primary staging and repeated staging (restaging) of non-small-cell lung cancer (NSCLC).

METHODS

In this retrospective study, all consecutive patients undergoing primary staging and restaging after neoadjuvant chemo- or chemo-radiotherapy for NSCLC with EBUS, EUS, or EBUS combined with EUS (CUS) with fine needle aspiration biopsy and cytological examination and subsequent TEMLA from January 1, 2007 to December 31 2010, were included.

RESULTS

Primary staging was performed in 623 patients: EBUS in 351, EUS in 72, and CUS in 200 patients. TEMLA was performed for primary staging in 276 patients. There was no mortality and morbidity after EBUS or EUS. One patient died after TEMLA and morbidity rate after TEMLA was 7.2%. There was a significant difference between EBUS or EUS and TEMLA for sensitivity (87.8% and 96.2%; p < 0.01) and negative predictive value (82.5% and 99.6%; p < 0.01) in favor of TEMLA. In the restaging group, endoscopic staging was performed in 88 patients and TEMLA in 78 patients. There was a significant difference between EBUS or EUS and TEMLA for sensitivity (64.3% and 100%; p < 0.01) and negative predictive value (82.1% and 100%; p < 0.01) in favor of TEMLA.

CONCLUSIONS

The results of this largest reported series comparing the endoscopic and surgical primary staging and restaging of NSCLC showed a significantly higher diagnostic yield of TEMLA when compared with that of EBUS or EUS.

The role of segmental nodes in the pathological staging of non-small cell lung cancer

Background

Segmental nodes are not examined routinely in current clinical practice for lung cancer, the role of segmental nodes in pathological staging of non-small cell lung cancer after radical resection was investigated.

Methods

A total of 113 consecutive non-small cell lung cancer patients who underwent radical resection between June 2009 and December 2011 were retrospectively reviewed. All the operations were performed by the same group of surgeons. N2 nodes, hilar nodes, interlobar nodes and some lobar nodes were collected during surgery. The removed lung lobes were dissected routinely along lobar and segmental bronchi to collect lobar nodes and segmental nodes. The collected lymph nodes were separately labeled for histological examination.

Results

The detection rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 61.1%, 85.0%, 75.2% and 80.5%, respectively. The metastasis rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 5.3%, 10.5%, 16.8% and 14.2%, respectively. There were 68 cases of N0 disease, 16 cases of N1 disease and 29 cases of N2 disease. If an analysis of segmental lymph nodes had been omitted, six patients (37.5% of N1 disease) would have been down-staged to N0, and two cases of multiple-zone N1 disease would have been misdiagnosed as single-zone N1 disease, one patient would have been misdiagnosed as N2 disease with skip metastases.

Conclusion

Segmental nodes play an important role in the accurate staging of non-small cell lung cancer, and routinely dissecting the segmental bronchi to collect the lymph nodes is feasible and may be necessary.

Number of lymph nodes associated with maximal reduction of long-term mortality risk in pathologic node-negative non-small cell lung cancer

BACKGROUND

Forty-four percent of patients with pathologic node negative (pN0) non-small cell lung cancer (NSCLC) die within 5 years of curative-intent surgical procedures. Heterogeneity in pathologic nodal examination practice raises concerns about the accuracy of nodal staging in these patients. We hypothesized a reciprocal relationship between the number of lymph nodes examined and the probability of missed lymph node metastasis and sought to identify the number of lymph nodes associated with the lowest mortality risk in pN0 NSCLC.

METHODS

We analyzed resections for first primary pN0 NSCLC in the United States Surveillance, Epidemiology, and End Results (SEER) database from 1998 to 2009, with survival updated to December 31, 2009.

RESULTS

In 24,650 eligible patients, there was a significant sequential reduction in mortality risk with examination of more lymph nodes. The lowest mortality risk occurred in those with 18 to 21 lymph nodes examined. The hazard ratio for all-cause mortality was 0.65 and the 95% confidence interval (CI) was 0.57 to 0.73; for lung cancer-specific mortality, hazard ratio was 0.62 and CI was 0.53 to 0.73 (p<0.001 for both). The median number of lymph nodes examined was only 6.

CONCLUSIONS

Lymph node evaluation falls far short of optimal in patients with resected pN0 NSCLC, raising the odds of underestimation of long-term mortality risk and failure to identify candidates for postoperative adjuvant therapy. This represents a major quality gap for which corrective intervention is warranted.

Towards optimal pathologic staging of resectable non-small cell lung cancer

Pathologic nodal staging is the most accurate means of determining prognosis of patients with resectable non-small cell lung cancer (NSCLC), but confusion prevails about the optimal pre-operative and surgical lymph node examination procedures for candidates of curative-intent resection. The landmark American College of Surgeons Oncology Group Z0030 trial revealed no difference in the survival of patients with clinical T1 or T2, N0 or N1 (hilar node-negative), M0 NSCLC who either had a fastidious, pre-defined systematic hilar and mediastinal lymph node sampling procedure, or who received a complete mediastinal lymph node dissection. We place the results of this major trial into a contemporary clinical practice context, and discuss problems associated with apparent misunderstanding of the lessons from this trial, especially in light of evidence of prevailing sub-optimal nodal examination practices. We also discuss evolving knowledge about the origin of the quality gap in pathologic nodal staging and the emerging literature on corrective interventions.

Dual intervention to improve pathologic staging of resectable lung cancer

BACKGROUND

Detection of lymph node metastasis is of immense prognostic value in patients with resectable non-small cell lung cancer (NSCLC), but routine pathologic nodal staging is suboptimal. To determine the impact on the rate of detection of nodal metastasis, we tested dual intervention with a prelabeled lymph node specimen collection kit to improve intraoperative node dissection and a fastidious gross dissection of the lung resection specimen for intrapulmonary lymph nodes.

METHODS

We matched dual-intervention cases with controls staged using standard surgical specimen collection and pathologic examination protocols. Controls were hierarchically matched for extent of resection, laterality, surgeon, pathologist, and T stage. All statistical comparisons were made with exact conditional logistic regression, to account for the matched case-control design.

RESULTS

One hundred dual-intervention cases were matched with 100 controls. The dual interventions resulted in approximately a 3-fold increase in the number of lymph nodes examined and the number of lymph nodes with metastasis detected; they also increased the proportion of patients with lymph node metastasis from 21% to 35% (p = 0.02). There were strong trends toward higher aggregate stage distribution, and eligibility for postoperative adjuvant chemotherapy in the dual-intervention cases.

CONCLUSIONS

The combination of interventions improved the thoroughness and accuracy of pathologic nodal staging. A prospective randomized trial to test the survival impact of the dual interventions is warranted.

Endobronchial ultrasound-guided transbronchial needle aspiration for differentiating N0 versus N1 lung cancer

BACKGROUND

The aim of this study was to assess the value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for differentiating cN0 versus cN1 non-small cell lung cancer.

METHODS

A retrospective review of EBUS-TBNA results in patients with potentially resectable clinical N0 or N1 non-small cell lung cancer based on computed tomography and positron emission tomography was performed. Systematic mediastinal and hilar lymph node sampling was performed by EBUS-TBNA. Lymph nodes larger than 5 mm in short axis or suspicious nodes were targeted. In the absence of N2 or N3 disease, patients underwent resection with lymph node dissection.

RESULTS

A total of 981 patients underwent EBUS-TBNA during the study period, of which 163 patients met the study criteria. There were 94 cN0 and 69 cN1 patients. A total of 453 lymph nodes (338 mediastinal and 115 N1 lymph nodes, average 2.8 nodes/patient) were sampled. Endobronchial ultrasound upstaged 9 (5.5%) patients to N2 disease, but was falsely negative in the mediastinum in 7 (4.3%) patients. In cN0 patients, EBUS confirmed N0 in 87 (53.4%) and upstaged in 7 (4.3%, N1 in 1, N2 in 6). In cN1 patients, EBUS confirmed N1 in 19 (11.7%), downstaged in 47 (28.8%), and upstaged in 3 (1.8%). The sensitivity, specificity, diagnostic accuracy, and negative predictive value of EBUS-TBNA to accurately differentiate between N0 and N1 disease was 76.2%, 100%, 96.6%, and 96.2%, respectively. The accuracy of mediastinal staging was 95.7%.

CONCLUSIONS

Endobronchial ultrasound-guided transbronchial needle aspiration can accurately access the hilar and interlobar lymph nodes in patients with potentially resectable lung cancer. Accurate assessment of cN0 versus cN1 by EBUS-TBNA may be used to guide induction therapy before surgery.

Outcome of platinum-based chemotherapy for non-small-cell lung cancer patients with pleural dissemination detected during surgery

Pleural dissemination detected by computed tomography (CT) is considered to be unfavorable for patients with non-small-cell lung cancer (NSCLC). However, the prognosis of NSCLC patients who are diagnosed with pleural dissemination at the time of surgery has yet to be adequately elucidated. To assess the outcomes of platinum-based chemotherapy in NSCLC patients in whom pleural dissemination was detected during exploratory thoracotomy with or without a videoscope, the clinical records of NSCLC patients who were admitted to Shizuoka Cancer Center between September, 2002 and April, 2009 were reviewed. A total of 19 patients were included in this study, 12 males and 7 females, with a median age of 65 years. All patients were diagnosed with adenocarcinoma and 6 were epidermal growth factor receptor (EGFR) gene mutation-positive. The median number of treatment cycles of first-line platinum-based chemotherapy was 4 (range, 1-6 cycles) and the objective response rate was 21% [95% confidence interval (CI): 8.5-43]. The median progression-free and overall survival were 10.4 (95% CI: 6.3-18.4) and 50.5 months (95% CI: 32.5-98.0), respectively. Of the 18 patients with reported disease progression, 9 (50%) developed locoregional tumor progression. In conclusion, NSCLC patients in whom pleural dissemination is detected during surgery tend to have a favorable prognosis for survival. Systemic chemotherapy and additional local treatment may improve their clinical outcomes.