Mediastinal Staging with Endobronchial Ultrasound in Early-Stage Non-Small Cell Lung Cancer: Is It Necessary?

Herein we examine the need for minimally invasive mediastinal staging for patients with early-stage non-small cell lung cancer (NSCLC) using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Early NSCLC, stages 1 and 2, has a 5-year survival rate between 53 and 92%, whereas stages 3 and 4 have a 5-year survival of 36% and below. With more favorable outcomes in earlier stages, greater emphasis has been placed on identifying lung cancer earlier in its disease process. Accurate staging is crucial as it dictates both prognosis and therapy. Inaccurate staging can adversely impact surgical candidacy (if falsely "over-staged") or lead to inadequate treatment (if "under-staged"). Clinical staging utilizes noninvasive methods to evaluate the anatomic extent of disease; however, it remains controversial whether mediastinal staging of early NSCLC with radiological exams alone is sufficient. EBUS-TBNA has altered the landscape of invasive mediastinal staging and is a crucial component to improving confidence in lung cancer staging, specifically in early NSCLC. Radiographic occult lymph node metastasis identified upon review of surgical resection specimens of early NSCLC may support the argument to perform EBUS-TBNA in all cases of early-stage disease. Other data suggest that EBUS-TBNA could be spared in cases of peripheral cT1aN0 and cT1bN0 for which surgical resection with lymph node dissection is planned. By reviewing reported EBUS-TBNA outcomes in patients with early NSCLC, we aim to emphasize the necessity of staging with EBUS in this population.

Transcervical Extended Mediastinal Lymphadenectomy: Experience From a North American Cancer Center

BACKGROUND

Accurate staging of the mediastinum is a critical element of therapeutic decision making in non-small cell lung cancer. We sought to determine the utility of transcervical extended mediastinal lymphadenectomy (TEMLA) in staging non-small cell lung cancer for large central tumors and after induction therapy.

METHODS

A retrospective record review was performed of all patients who underwent TEMLA at our institution from 2010 to 2015. Clinical stage as assessed by positron emission tomography integrated with computed tomography (PET-CT), stage as assessed by TEMLA, final pathologic stage, lymph node yield, and clinical characteristics of tumors were assessed along with TEMLA-related perioperative morbidity. Accuracy of staging by TEMLA for restaging the mediastinum after neoadjuvant therapy was compared with that of PET-CT.

RESULTS

Of 164 patients who underwent TEMLA, 157 (95.7%) were completed successfully. Combined surgical resection along with TEMLA was performed in 138 of these patients, with 131 (94.2%) undergoing a video-assisted thoracoscopic resection. The recurrent laryngeal nerve injury rate was 6.7%. TEMLA was performed in 118 of 164 patients for restaging after neoadjuvant therapy, and 101 of these patients were also restaged by PET-CT. Based on TEMLA, 7 patients did not go on to have resection. Of the 101 patients who did have a resection, TEMLA was more accurate than PET-CT in staging the mediastinum (95% vs 73%, p < 0.0001). However, the pneumonia rate in this subgroup of patients was 13%.

CONCLUSIONS

TEMLA is a safe procedure and superior to PET-CT for restaging of the mediastinum after neoadjuvant therapy for non-small cell lung cancer. However, this increased accuracy comes with a high postoperative pneumonia rate.

Indications for invasive mediastinal staging in patients with early non-small cell lung cancer staged with PET-CT

PURPOSE/OBJECTIVE(S)

Appropriate use of invasive mediastinal staging in patients with clinically node-negative NSCLC staged by PET-CT is critical in selecting patients for curative-intent therapy such as surgery or SBRT, but little data exists to guide this decision-making. We examined a large population of patients with clinical stage I NSCLC referred for mediastinoscopy or EBUS to find risk factors for occult N2 lymph nodes and determine which patients benefit from invasive staging.

MATERIALS/METHODS

We identified consecutive clinical T1-2N0 NSCLC patients being evaluated for curative-intent therapy between 2011 and 2015. None had evidence of nodal disease by PET-CT; the endpoint was pathologic confirmation of occult N2 disease by EBUS or mediastinoscopy. Tumor size, location, histology, SUV_max, and radiographic appearance were evaluated as determinants of occult N2 disease. Two group comparisons of continuous variables were done with independent t-tests and categorical variables were compared with χ² or Fisher's exact test.

RESULTS

In 284 patients with PET-CT-staged clinical T1-2N0 disease, the prevalence of occult N2 metastases was 7.0%. The negative predictive value of PET-CT was 92.9% and the negative predictive value of mediastinoscopy/EBUS was 96.3%. T2 tumors were more likely to have occult N2 disease than T1 tumors (11.8% v 3.6% p=0.009). Pure solid tumors had greater involvement of N2 nodes than tumors with any ground glass component (12.6% v 3.1%, p<0.001). 17.5% of central tumor cases were found to have occult N2 metastases while 4.4% of patients with peripheral tumors (P<0.001). 33.3% of patients with solid central T2 tumors had occult N2 metastases whereas 2.0% of patients with peripheral T2 tumors with a ground glass component, 1.2% of patients with peripheral T1 tumors with a ground glass component and 3.6% of patients with peripheral T1 solid tumors had N2 metastases.

CONCLUSIONS

Invasive mediastinal staging should be strongly encouraged in central tumors and solid T2 tumors because the risk of occult nodal involvement is greater than 10% in these cohorts. However, for patients with peripheral T1 tumors or peripheral T2 tumors with a significant ground glass component, the yield of invasive staging after a negative PET-CT is very low and invasive staging may not be warranted.

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.

Mediastinoscopy: trends and practice patterns in the United States

OBJECTIVES

Historically, mediastinoscopy has been the gold standard for the staging of lung cancer. A practice gap exists as the result of a variation in knowledge concerning current trends and practice patterns of mediastinoscopy usage. In addition, there are regional variations in practice-based learning and patient care. Lessons learned during surgeries performed on patients with lung cancer and other advances such as positron emission tomography and endobronchial ultrasound could be universally applied to improve surgeons' management of patient care. The purpose of this study was to assess contemporary practices in the staging of lung cancer.

METHODS

We queried the Society of Thoracic Surgeons National Database for data regarding mediastinoscopy usage, yield, and variation, both by year and region.

RESULTS

Cases with mediastinoscopy, as a percentage of all cases performed in the database, have significantly decreased from 14.6% in 2006 to 11.4% in 2010 (P < 0.001). The 5-year median rate of mediastinoscopy in lung cancer patients at 163 centers was 15.3% (interquartile range 5.2%-31.7%), indicating significant variation among centers. The overall median center rate also decreased over time from 21.4% (2006) to 10.0% (2010).

CONCLUSIONS

With advances in minimally invasive procedures and imaging, mediastinoscopy usage has declined significantly. Our findings are likely to be relevant to both clinical practice and practice guidelines.

Clinical and surgical-pathological staging in early non-small cell lung cancer

Staging is of the utmost importance in the evaluation of a patient with non-small cell lung cancer (NSCLC) because it defines the actual extent of the disease. Accurate staging allows multidisciplinary oncology teams to plan the best surgical or medical treatment and to predict patient prognosis. Based on the recommendation of the International Association for the Study of Lung Cancer (IASLC), a tumor, node, and metastases (TNM) staging system is currently used for NSCLC. Clinical staging (c-TNM) is achieved via non-invasive modalities such as examination of case history, clinical assessment and radiological tests. Pathological staging (p-TNM) is based on histological examination of tissue specimens obtained with the aid of invasive techniques, either non-surgical or during the intervention. This review is a critical evaluation of the roles of current pre-operative staging modalities, both invasive and non-invasive. In particular, it focuses on new techniques and their role in providing accurate confirmation of patient TNM status. It also evaluates the surgical-pathological staging modalities used to obtain the true-pathological staging for NSCLC.

Staging the mediastinum: what is current best practice?

SUMMARY Staging of the mediastinum has long been a part of essential best practice in lung cancer management. This review aims to provide an overview of important key issues, such as anatomical considerations from the 2009 International Association for the Study of Lung Cancer lymph node map, as well as noninvasive and invasive staging techniques for the mediastinum. A suggested sequence of staging the mediastinum is provided, which is by no means prescriptive, but will evolve over time as more evidence is gathered regarding this important step in the clinical work-up of lung cancer patients.

Advances in bronchoscopy for lung cancer

Bronchoscopic techniques have seen significant advances in the last decade. The development and refinement of different types of endobronchial ultrasound and navigation systems have led to improved diagnostic yield and lung cancer staging capabilities. The complication rate of these minimally invasive procedures is extremely low as compared to traditional transthoracic needle biopsy and surgical sampling. These advances augment the safe array of methods utilized in the work up and management algorithms of lung cancer.