Systematic endoscopic staging of mediastinum to guide radiotherapy planning in patients with locally advanced non-small-cell lung cancer (SEISMIC): an international, multicentre, single-arm, clinical trial

BACKGROUND

Systematic mediastinal lymph node staging by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) improves accuracy of staging in patients with early-stage non-small-cell lung cancer (NSCLC). However, patients with locally advanced NSCLC commonly undergo only selective lymph node sampling. This study aimed to determine the proportion of patients with locally advanced NSCLC in whom systematic endoscopic mediastinal staging identified PET-occult lymph node metastases, and to describe the consequences of PET-occult disease on radiotherapy planning.

METHODS

This prospective, international, multicentre, single-arm, international study was conducted at seven tertiary lung cancer centres in four countries (Australia, Canada, the Netherlands, and the USA). Patients aged 18 years or older with suspected or known locally advanced NSCLC underwent systematic endoscopic mediastinal lymph node staging before combination chemoradiotherapy or high-dose palliative radiotherapy. The primary endpoint was the proportion of participants with PET-occult mediastinal lymph node metastases shown following systematic endoscopic staging. The study was prospectively registered with Australian New Zealand Clinical Trials Registry, ACTRN12617000333314.

FINDINGS

From Jan 30, 2018, to March 23, 2022, 155 patients underwent systematic endoscopic mediastinal lymph node staging and were eligible for analysis. 58 (37%) of patients were female and 97 (63%) were male. Discrepancy in extent of mediastinal disease identified by PET and EBUS-TBNA was observed in 57 (37% [95% CI 29-44]) patients. PET-occult lymph node metastases were identified in 18 (12% [7-17]) participants, including 16 (13% [7-19]) of 123 participants with clinical stage IIIA or cN2 NSCLC. Contralateral PET-occult N3 disease was identified in nine (7% [2-12]) of 128 participants staged cN0, cN1, or cN2. Identification of PET-occult disease resulted in clinically significant changes to treatment in all 18 patients. In silico dosimetry studies showed the median volume of PET-occult lymph nodes receiving the prescription dose of 60 Gy was only 10·1% (IQR 0·1-52·3). No serious adverse events following endoscopic staging were reported.

INTERPRETATION

Our findings suggests that systematic endoscopic mediastinal staging in patients with locally advanced or unresectable NSCLC is more accurate than PET alone in defining extent of mediastinal involvement. Standard guideline-recommended PET-based radiotherapy planning results in suboptimal tumour coverage. Our findings indicate that systematic endoscopic staging should be routinely performed in patients with locally advanced NSCLC being considered for radiotherapy to accurately inform radiation planning and treatment decision making in patients with locally advanced NSCLC.

FUNDING

None.

The European Respiratory Society led training programme improves self-reported competency and increases the use of thoracic ultrasound

Thoracic ultrasound has become a well-implemented diagnostic tool for assessment and monitoring of patients with respiratory symptoms or disease. However, ultrasound examinations are user dependent and sufficient competencies are needed. The European Respiratory Society (ERS) hosts a structured and evidence-based training programme in thoracic ultrasound. This study aimed to explore and discuss the self-reported activity and self-reported competency of the participants during the ERS course. Online surveys were sent to the training programme participants before the second part of the course (practical part of the course), and before and 3 months after the third part of the course (final certification exam). A total of 77 participants completed the surveys. The self-reported frequency of thoracic ultrasound examinations increased during the course, and in the final survey more than 90% of the participants used thoracic ultrasound on weekly basis. The self-reported competency (on technical execution of the thoracic ultrasound examination and overall competency) also increased. The ERS thoracic ultrasound training programme forms the basis of broad theoretical knowledge and sufficient practical skills that seem to lead to behavioural changes, whereby a large proportion of the participants implemented ultrasound in their clinical practice.

Using the Endoscope for Endobronchial Ultrasound in the Esophagus

EUS-B is a procedure using the echoendobronchoscope in the esophagus and stomach. The procedure is a minimally invasive, safe, and feasible approach that pulmonologists can use to visualize and biopsy structures adjacent to the esophagus and stomach. EUS-B gives access to many structures of which some may also be reached by EBUS (mediastinal lymph nodes, lung or pleural tumors, pericardial fluid) while others cannot be reached such as retroperitoneal lymph nodes, ascites, and lesions in the liver, pancreas or left adrenal gland. The procedure is a pulmonologist- and patient- friendly version of the gastroenterologists' EUS using the thin EBUS endoscope that the pulmonologist already masters. Thus EUS-B training should be easy and a natural continuation of EBUS. With the patient under conscious sedation and in the supine position, the echoendoscope is introduced either through the nostril or mouth into the oropharynx. Then the patient is encouraged to swallow while the endoscope is slowly bent posteriorly and introduced into the esophagus and stomach. Using the ultrasonic image, the operator identifies the six landmarks by EUS-B and EUS: the left liver lobe, abdominal aorta (with the celiac trunk and superior mesenteric artery), left adrenal gland, and mediastinal lymph node stations 7, 4L, and 4R. Biopsies can be taken from suspected lesions under real-time ultrasonographic guidance- fine needle aspiration (EUS-B-FNA) using a technique similar to that used with EBUS-TBNA. The biopsy order is M1b-M1a-N3-N2-N1-T (M = metastasis, N = lymph node, T = tumor) to avoid iatrogenic upstaging. Pre- and post-procedural observation is similar to that of bronchoscopy. EUS-B is safe and feasible in the hands of experienced interventional pulmonologists and provides a significant expansion of the diagnostic possibilities in providing safe, fast, and thorough diagnosis and staging of lung cancer.

Dosimetric Impact of Systematic Mediastinal Staging via Endobronchial Ultrasound for Patients with Locally Advanced Lung Cancer: The SEISMIC Trial

PURPOSE/OBJECTIVE(S)

The SEISMIC trial aims to find the best method for mediastinal staging in patients with lung cancer receiving chemoradiotherapy. Currently, CT or PET-CT scans are standard in clinical practice, but histological evaluation of the mediastinum is performed on a case-by-case basis. The study will examine the effect of systematic histological evaluation using Endobronchial Ultrasound (EBUS) on radiotherapy target volumes. The hypothesis of this study is that differences in staging between the diagnostic PET-CT and EBUS would result in reduced tumor coverage and/or increased doses to organs at risk (OAR).

MATERIALS/METHODS

SEISMIC is a prospective multicenter international cohort study. Patients were enrolled from Australia, the Netherlands, USA and Canada after regional IRB approvals. Patients were treated with 4DCT simulation. Two iGTV and PTV target volumes were delineated for each patient with discordant staging according to both PET-CT and EBUS, as were OARs. Two VMAT plans were generated for each patient based on either PET-CT or EBUS target volumes using knowledge-based planning methodology. Plans aimed to achieve institutional guidelines for target coverage and OAR dose constraints, with a prescribed dose of 60 Gy in 30 fractions. Target coverage and OAR doses for the PET- and EBUS-defined volumes were compared.

RESULTS

In 156 patients, EBUS showed a larger extent of disease than PET in 18 (11.5%) and a smaller extent of lymph node (LN) involvement than PET in 49 (31.4%). Out of 67 patients with PET-EBUS discordant results, 25 underwent upfront radiotherapy and were included in the study. EBUS revealed PET-occult LN involvement in 11/25 patients (44%). In these patients, 10/11 patients received <95% of the prescribed dose to PET-occult LN iGTVs; the median [range] minimum dose to the EBUS iGTV was 9.2 Gy [0.1 - 57.9 Gy]. When planning based on EBUS LN involvement, all patients received ≥95% of the prescribed dose to the iGTV (the median [range] minimum dose to the EBUS iGTV was 58.9 Gy [58.1 - 60.5 Gy]). This resulted in increased median [range] doses to OARs; mean lung dose increased by 1.1 Gy [0.3 - 8.4 Gy], esophagus mean dose increased by 3.6 Gy [0.2 - 24.8 Gy], and mean heart dose increased by 0.5 Gy [-0.6 - 8.5 Gy].

CONCLUSION

Systematic endoscopic evaluation of the mediastinum had a significant effect on tumor coverage in a clinically meaningful proportion of cases and consequent plan adaptation impacted on organ-at-risk (OAR) doses. Results suggest systematic mediastinal LN staging should be considered in all patients prior to curative-intent radiotherapy.

CLINICAL TRIAL ID

ACTRN12617000333314.

Evidence-based training and certification: the ERS thoracic ultrasound training programme

Thoracic ultrasound has developed into an integral part of the respiratory physician's diagnostic and therapeutic toolbox, with high diagnostic accuracy for many diseases causing acute or chronic respiratory symptoms. However, it is vitally important that the operator has received the appropriate education and training to ensure a systematic and thorough examination, correct image interpretation, and that they then have the appropriate skills to integrate all the findings for patient benefit. In this review, we present the new European Respiratory Society thoracic ultrasound training programme, including a discussion of curriculum development, its implementation, and trainee evaluation. This programme enables participants to gain competence in thoracic ultrasound through structured, evidence-based training with robustly validated assessments and certification. The training programme consists of three components: an online, theoretical part (part 1), which is accessible all year; a practical course (part 2), with four courses held each year (two online courses and two on-site courses); and an examination (part 3) comprising an objective structured clinical examination (OSCE), which is hosted each year at the European Respiratory Society Congress.

Surprising impact of stromal TIL's on immunotherapy efficacy in a real-world lung cancer study

INTRODUCTION

Immune checkpoint inhibitors (ICI), such as anti-PD-1 agents, have become part of the standard of care treatment of advanced non-small cell lung cancer (NSCLC). Predictive biomarkers are needed to identify patients that benefit from anti-PD-1 treatments. Tumor infiltrating lymphocytes (TILs) and PD-L1 are major players in the ICI mechanism of action. In this study, we assess the impact of real-world clinicopathological variables, including TILs and PD-L1, on anti-PD-1 efficacy.

METHODS

We performed a monocenter retrospective study in advanced NSCLC treated with nivolumab or pembrolizumab between January 2015 and February 2019. The impact of baseline clinical and pathological variables was assessed by univariate and multivariate models. TILs, defined as CD8+T-cells, and PD-L1 were scored in tumor and stroma, and correlated with progression free survival (PFS) and overall survival (OS).

RESULTS

We included 366 patients of whom 141 were assessed for tumor and stromal TILs. The median follow-up time was 487 days. In the whole cohort, PFS was associated with high tumor PD-L1, high albumin and good performance. OS was associated with low LDH, high albumin, good performance and 'first-line treatment'. In the TILs subcohort, stromal TILs had the strongest impact on PFS and OS. Stromal TILs were a stronger marker for PFS and OS than tumoral TILs, tumoral PD-L1 or stromal PD-L1. Remaining factors for PFS and OS were albumin and albumin with LDH, respectively.

CONCLUSIONS

This real-world study on clinicopathological features shows that stromal CD8 + TILs were the strongest predictor for PFS and OS in patients with advanced NSCLC on anti-PD-1 therapy. Other predictors for PFS and OS included albumin and albumin together with LDH, respectively. This study highlights the pivotal role of the stromal compartment in the mechanisms of action of ICI, and the need for further studies aiming to overcome this stromal firewall.

Combined endobronchial and esophageal endosonography for the diagnosis and staging of lung cancer: European Society of Gastrointestinal Endoscopy (ESGE) Guideline, in cooperation with the European Respiratory Society (ERS) and the European Society of Thoracic Surgeons (ESTS)

This is an official guideline of the European Society of Gastrointestinal Endoscopy (ESGE), produced in cooperation with the European Respiratory Society (ERS) and the European Society of Thoracic Surgeons (ESTS). It addresses the benefit and burden associated with combined endobronchial and esophageal mediastinal nodal staging of lung cancer. The Scottish Intercollegiate Guidelines Network (SIGN) approach was adopted to define the strength of recommendations and the quality of evidence.The article has been co-published with permission in the European Journal of Cardio-Thoracic Surgery and the European Respiratory Journal. Recommendations 1 For mediastinal nodal staging in patients with suspected or proven non-small-cell lung cancer (NSCLC) with abnormal mediastinal and/or hilar nodes at computed tomography (CT) and/or positron emission tomography (PET), endosonography is recommended over surgical staging as the initial procedure (Recommendation grade A). The combination of endobronchial ultrasound with real-time guided transbronchial needle aspiration (EBUS-TBNA) and endoscopic (esophageal) ultrasound with fine needle aspiration, with use of a gastrointestinal (EUS-FNA) or EBUS (EUS-B-FNA) scope, is preferred over either test alone (Recommendation grade C). If the combination of EBUS and EUS-(B) is not available, we suggest that EBUS alone is acceptable (Recommendation grade C).Subsequent surgical staging is recommended, when endosonography does not show malignant nodal involvement (Recommendation grade B). 2 For mediastinal nodal staging in patients with suspected or proven non-small-cell peripheral lung cancer without mediastinal involvement at CT or CT-PET, we suggest that EBUS-TBNA and/or EUS-(B)-FNA should be performed before therapy, provided that one or more of the following conditions is present: (i) enlarged or fluorodeoxyglucose (FDG)-PET-avid ipsilateral hilar nodes; (ii) primary tumor without FDG uptake; (iii) tumor size ≥ 3 cm (Fig. 3a - c) (Recommendation grade C). If endosonography does not show malignant nodal involvement, we suggest that mediastinoscopy is considered, especially in suspected N1 disease (Recommendation grade C).If PET is not available and CT does not reveal enlarged hilar or mediastinal lymph nodes, we suggest performance of EBUS-TBNA and/or EUS-(B)-FNA and/or surgical staging (Recommendation grade C). 3 In patients with suspected or proven < 3 cm peripheral NSCLC with normal mediastinal and hilar nodes at CT and/or PET, we suggest initiation of therapy without further mediastinal staging (Recommendation grade C). 4 For mediastinal staging in patients with centrally located suspected or proven NSCLC without mediastinal or hilar involvement at CT and/or CT-PET, we suggest performance of EBUS-TBNA, with or without EUS-(B)-FNA, in preference to surgical staging (Fig. 4) (Recommendation grade D). If endosonography does not show malignant nodal involvement, mediastinoscopy may be considered (Recommendation grade D). 5 For mediastinal nodal restaging following neoadjuvant therapy, EBUS-TBNA and/or EUS-(B)-FNA is suggested for detection of persistent nodal disease, but, if this is negative, subsequent surgical staging is indicated (Recommendation grade C). 6 A complete assessment of mediastinal and hilar nodal stations, and sampling of at least three different mediastinal nodal stations (4 R, 4 L, 7) (Fig. 1, Fig. 5) is suggested in patients with NSCLC and an abnormal mediastinum by CT or CT-PET (Recommendation grade D). 7 For diagnostic purposes, in patients with a centrally located lung tumor that is not visible at conventional bronchoscopy, endosonography is suggested, provided the tumor is located immediately adjacent to the larger airways (EBUS) or esophagus (EUS-(B)) (Recommendation grade D). 8 In patients with a left adrenal gland suspected for distant metastasis we suggest performance of endoscopic ultrasound fine needle aspiration (EUS-FNA) (Recommendation grade C), while the use of EUS-B with a transgastric approach is at present experimental (Recommendation grade D). 9 For optimal endosonographic staging of lung cancer, we suggest that individual endoscopists should be trained in both EBUS and EUS-B in order to perform complete endoscopic staging in one session (Recommendation grade D). 10 We suggest that new trainees in endosonography should follow a structured training curriculum consisting of simulation-based training followed by supervised practice on patients (Recommendation grade D). 11 We suggest that competency in EBUS-TBNA and EUS-(B)-FNA for staging lung cancer be assessed using available validated assessment tools (Recommendation Grade D).