Impact of EBUS-TBNA in addition to [18F]FDG-PET/CT imaging on target volume definition for radiochemotherapy in stage III NSCLC

Impact of mediastinal tumor burden and lymphatic spread in locally advanced non-small-cell lung cancer: A secondary analysis of the multicenter randomized PET-Plan trial

PURPOSE

The aim of this secondary analysis of the prospective randomized phase 2 PET-Plan trial (ARO-2009-09; NCT00697333) was to evaluate the impact of mediastinal tumor burden and lymphatic spread in patients with locally advanced non-small-cell lung cancer (NSCLC).

METHODS

All patients treated per protocol (n = 172) were included. Patients received isotoxically dose-escalated chemoradiotherapy up to a total dose of 60-74 Gy in 30-37 fractions, aiming as high as possible while adhering to normal tissue constraints. Radiation treatment (RT) planning was based on an 18F-FDG PET/CT targeting all lymph node (LN) stations containing CT positive LNs (i.e. short axis diameter > 10 mm), even if PET-negative (arm A) or targeting only LN stations containing PET-positive nodes (arm B). LN stations were classified into echelon 1 (ipsilateral hilum), 2 (ipsilateral station 4 and 7), and 3 (rest of the mediastinum, contralateral hilum). The endpoints were overall survival (OS), progression-free survival (PFS), and freedom from local progression (FFLP).

RESULTS

The median follow-up time (95 % confidence interval [CI]) was 41.1 (33.8 - 50.4) months. Patients with a high absolute number of PET-positive LN stations had worse OS (hazard ratio [HR] = 1.09; 95 % CI 0.99 - 1.18; p = 0.05) and PFS (HR = 1.12; 95 % CI 1.04 - 1.20; p = 0.003), irrespective of treatment arm allocation. The prescribed RT dose to the LNs did not correlate with any of the endpoints when considering all patients. However, in patients in arm B (i.e., PET-based selective nodal irradiation), prescribed RT dose to each LN station correlated significantly with FFLP (HR=0.45; 95 % CI 0.24-0.85; p = 0.01). Furthermore, patients with involvement of echelon 3 LN stations had worse PFS (HR = 2.22; 95 % CI 1.16-4.28; p = 0.02), also irrespective of allocation.

CONCLUSION

Mediastinal tumor burden and lymphatic involvement patterns influence outcome in patients treated with definitive chemoradiotherapy for locally advanced NSCLC. Higher dose to LNs did not improve OS, but did improve FFLP in patients treated with PET-based dose-escalated RT.

Overestimation of contralateral hilar lymph node metastasis in non-metastatic non-small cell lung cancer and its predictive model: HAM

BACKGROUND AND PURPOSE

Metastasis of non-metastatic non-small cell lung cancer (NMNSCLC) to contralateral hilar lymph nodes (CHLN) eliminates the opportunity for radical therapy. This study aims to analyze whether CHLN metastasis in NMNSCLC is commonly overestimated in clinical practice and to establish a predictive model for enhanced precision.

METHODS AND MATERIALS

We conducted a retrospective analysis of 834 pathologically confirmed NMNSCLC patients. Monitoring of treatment responses and regular ≥ 1 year CT follow-up was used to determine the nature of CHLN. Lasso regression was used to select predictive factors, and a multivariate binary logistic regression model (HAM) was constructed. Internal validation was performed using ten-fold cross-validation.

RESULTS

The CHLN metastasis rate was 4.4% among the NMNSCLC patients. The positive predictive value (PPV) and sensitivity for PET-CT diagnosis were 36.8% and 67.5%, while for CT they are 44.8% and 70.2%, respectively. The five optimal predictive factors (emphysema or bullae, central-type lung cancer, short diameter of CHLN, calcification and SUVmax) were used to develop the HAM model. The Area under curve (AUC) values for PET-CT, CT, and HAM model were 0.81, 0.83, and 0.96, respectively. The F1 scores for PET-CT and CT were 0.48 and 0.55, respectively, while the maximum F1 score of our model was 0.73, with corresponding PPV and sensitivity of 66.7%, and 81.1%, respectively.

CONCLUSIONS

CHLN metastasis is rare in NMNSCLC patients. PET-CT diagnosis significantly overestimates CHLN metastasis and the HAM model improves clinical decision-making in this study. Prospective studies are needed to confirm these conclusions.

Can We Offset Local Recurrence in Locally Advanced Non-Small Cell Lung Cancer? The Merry-Go-Round of Radiation Dose Escalation and Stubborn Outcomes

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

C-reactive protein as robust laboratory value associated with prognosis in patients with stage III non-small cell lung cancer (NSCLC) treated with definitive radiochemotherapy

To evaluate the prognostic value of biomarkers from peripheral blood obtained as routine laboratory assessment for overall survival in a cohort of stage III non-small cell lung cancer (NSCLC) patients treated with definitive radiochemotherapy at a high-volume cancer center. Seven blood biomarkers from 160 patients treated with definitive radiochemotherapy for stage III NSCLC were analyzed throughout the course treatment. Parameters were preselected using univariable and multivariable proportional hazards analysis and were assessed for internal validity using leave-one-out cross validation. Cross validated classifiers including biomarkers in addition to important clinical parameters were compared with classifiers containing the clinical parameters alone. An increased C-reactive protein (CRP) value in the final week of radiotherapy was found as a prognostic factor for overall survival, both as a continuous (HR 1.099 (1.038-1.164), p < 0.0012) as well as categorical variable splitting data at the median value of 1.2 mg/dl (HR 2.214 (1.388-3.531), p < 0.0008). In the multivariable analysis, the CRP value-maintained significance with an HR of 1.105 (1.040-1.173) and p-value of 0.0012. The cross validated classifier using CRP at the end of radiotherapy in addition to clinical parameters separated equally sized high and low risk groups more distinctly than a classifier containing the clinical parameters alone (HR = 2.786 (95% CI 1.686-4.605) vs. HR = 2.287 (95% CI 1.407-3.718)). Thus, the CRP value at the end of radiation therapy has successfully passed the crucial cross-validation test. The presented data on CRP levels suggests that inflammatory markers may become increasingly important during definitive radiochemotherapy, particularly with the growing utilization of immunotherapy as a consolidation therapy for stage III NSCLC.

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.

[Prevention, Diagnosis, Therapy, and Follow-up of Lung Cancer - Interdisciplinary Guideline of the German Respiratory Society and the German Cancer Society - Abridged Version]

The current S3 Lung Cancer Guidelines are edited with fundamental changes to the previous edition based on the dynamic influx of information to this field:The recommendations include de novo a mandatory case presentation for all patients with lung cancer in a multidisciplinary tumor board before initiation of treatment, furthermore CT-Screening for asymptomatic patients at risk (after federal approval), recommendations for incidental lung nodule management , molecular testing of all NSCLC independent of subtypes, EGFR-mutations in resectable early stage lung cancer in relapsed or recurrent disease, adjuvant TKI-therapy in the presence of common EGFR-mutations, adjuvant consolidation treatment with checkpoint inhibitors in resected lung cancer with PD-L1 ≥ 50%, obligatory evaluation of PD-L1-status, consolidation treatment with checkpoint inhibition after radiochemotherapy in patients with PD-L1-pos. tumor, adjuvant consolidation treatment with checkpoint inhibition in patients withPD-L1 ≥ 50% stage IIIA and treatment options in PD-L1 ≥ 50% tumors independent of PD-L1status and targeted therapy and treatment option immune chemotherapy in first line SCLC patients.Based on the current dynamic status of information in this field and the turnaround time required to implement new options, a transformation to a "living guideline" was proposed.

Preoperative Hilar and Mediastinal Lymph Node Staging in Patients with Suspected or Diagnosed Lung Cancer: Accuracy of 18F-FDG-PET/CT:A Retrospective Cohort Study of 138 Patients

The aim of this study was to evaluate the diagnostic accuracy of integrated 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG-PET/CT) in hilar and mediastinal lymph node (HMLN) staging of suspected or proven lung cancer, and to investigate potential risk factors for false negative and false positive HMLN metastases. We retrospectively analyzed 162 consecutive patients with suspected or pathologically proven non-small cell lung cancer (NSCLC). The receiver operating characteristic (ROC) curve was generated to determine the diagnostic efficacy of 18F-FDG-PET/CT. Univariate and multivariate analyses were conducted to detect risk factors of false positives and false negatives. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of integrated 18F-FDG-PET/CT in detecting HMLN metastases were 59.1% (26/44), 69.1% (65/94), 47.3% (26/55), 78.3% (65/83), and 65.9% (91/138), respectively. The ROC curve showed an area under the curve (AUC) of 0.625 (95%-CI 0.468-0.782). The incidence of false negative and false positive HMLN metastases was 21.7% (18/83) and 52.7% (29/55), respectively. Our data shows that integrated 18F-FDG-PET/CT staging provides lower specificity and sensitivity. This confirms the ESTS guideline on lymph node staging for PET-positive HMLN. Yet it advocates more invasive staging even for PET-negative HMLN.

[The role of endoscopy in exploration of the mediastinum, indications and results]

Since 2005, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a standard pulmonological tool. The procedure is safe and well tolerated by patients, with minimal morbidity and almost no mortality. A previous review on the technique was published in 2012. However, over the last ten years, a number of new studies have been published on "benign" (sarcoidosis, tuberculosis…) as well as "malignant" diseases (lung cancer, metastases of extra-thoracic cancers, search for mutations and specific oncogenic markers…). These developments have led to expanded indications for EBUS-TBNA, with which it is indispensable to be familiar, in terms of "staging" as well as "diagnosis". In view of optimizing lymph node sampling, several publications have described and discussed EBUS exploration by means of newly available tools (biopsy forceps, larger needles…), and proposed interpretation of the images thereby produced. Given the ongoing evolution of linear EBUS, it seemed indispensable that information on this marvelous tool be updated. This review is aimed at summarizing the novel elements we have found the most important.

Prediction of malignant lymph nodes in NSCLC by machine-learning classifiers using EBUS-TBNA and PET/CT

Accurate determination of lymph-node (LN) metastases is a prerequisite for high precision radiotherapy. The primary aim is to characterise the performance of PET/CT-based machine-learning classifiers to predict LN-involvement by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in stage-III NSCLC. Prediction models for LN-positivity based on [¹⁸F]FDG-PET/CT features were built using logistic regression and machine-learning models random forest (RF) and multilayer perceptron neural network (MLP) for stage-III NSCLC before radiochemotherapy. A total of 675 LN-stations were sampled in 180 patients. The logistic and RF models identified SUV_max, the short-axis LN-diameter and the echelon of the considered LN among the most important parameters for EBUS-positivity. Adjusting the sensitivity of machine-learning classifiers to that of the expert-rater of 94.5%, MLP (P = 0.0061) and RF models (P = 0.038) showed lower misclassification rates (MCR) than the standard-report, weighting false positives and false negatives equally. Increasing the sensitivity of classifiers from 94.5 to 99.3% resulted in increase of MCR from 13.3/14.5 to 29.8/34.2% for MLP/RF, respectively. PET/CT-based machine-learning classifiers can achieve a high sensitivity (94.5%) to detect EBUS-positive LNs at a low misclassification rate. As the specificity decreases rapidly above that level, a combined test of a PET/CT-based MLP/RF classifier and EBUS-TBNA is recommended for radiation target volume definition.

Systematic endoscopic staging of mediastinum to determine impact on radiotherapy for locally advanced lung cancer (SEISMIC): protocol for a prospective single arm multicentre interventional study

Background

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is established as the preferred method of mediastinal lymph node (LN) staging in non-small cell lung cancer (NSCLC). Selective (targeted) LN sampling is most commonly performed however studies in early stage NSCLC and locally advanced NSCLC confirm systematic EBUS-TBNA evaluation improves accuracy of mediastinal staging. This study aims to establish the rate of detection of positron emission tomography (PET)-occult LN metastases following systematic LN staging by EBUS-TBNA, and to determine the utility of systematic mediastinal staging for accurate delineation of radiation treatment fields in patients with locally advanced NSCLC.

Methods

Consecutive patients undergoing EBUS-TBNA for diagnosis/staging of locally advanced NSCLC will be enrolled in this international multi-centre single arm study. Systematic mediastinal LN evaluation will be performed, with all LN exceeding 6 mm to be sampled by TBNA. Where feasible, endoscopic ultrasound staging (EUS-B) may also be performed. Results of minimally invasive staging will be compared to FDG-PET. The primary end-point is proportion of patients in whom systematic LN staging identified PET-occult NSCLC metastases. Secondary outcome measures include (i) rate of nodal upstaging, (ii) false positive rate of PET for mediastinal LN assessment, (iii) analysis of clinicoradiologic risk factors for presence of PET-occult LN metastases, (iv) impact of systematic LN staging in patients with discrepant findings on PET and EBUS-TBNA on target coverage and dose to organs at risk (OAR) in patients undergoing radiotherapy.

Discussion

With specificity of PET of 90%, guidelines recommend tissue confirmation of positive mediastinal LN to ensure potentially early stage patients are not erroneously denied potentially curative resection. However, while confirmation of pathologic LN is routinely sought, the exact extent of mediastinal LN involvement in NSCLC in patient with Stage III NSCLC is rarely established. Studies examining systematic LN staging in early stage NSCLC report a significant discordance between PET and EBUS-TBNA. In patients with locally advanced disease this has significant implications for radiation field planning, with risk of geographic miss in the event of PET-occult mediastinal LN metastases. The SEISMIC study will examine both diagnostic outcomes following systematic LN staging with EBUS-TBNA, and impact on radiation treatment planning.

Trial registration

ACTRN12617000333314, ANZCTR, Registered on 3 March 2017.

Effectiveness of durvalumab consolidation in stage III non-small-cell lung cancer: focus on treatment selection and prognostic factors

The pivotal PACIFIC trial defined durvalumab consolidation as the new standard of care in patients with stage III non-small-cell lung cancer treated with definitive radiochemotherapy. The authors characterized the durvalumab effect after induction chemotherapy according to the ESPATUE trial and definitive radiochemotherapy. All consecutive patients with stage III non-small-cell lung cancer receiving definitive radiochemotherapy between January 2017 and February 2020 were included. Primary end points were progression-free survival and overall survival. Altogether, 160 patients (75 PD-L1-positive, 62 PD-L1-negative, 23 unknown) received definitive radiochemotherapy, 146 (91%) of whom received prior induction chemotherapy. Durvalumab consolidation showed high effectiveness overall and in the good-risk group according to the PACIFIC trial (log-rank test: p < 0.005). Hazard ratios for progression-free survival and overall survival were at the lower limits of those in the PACIFIC trial. These results were robust to adjustment for potential confounders by propensity score weighting. Eastern Cooperative Oncology Group (ECOG) performance status was the most important pretreatment prognostic factor.

Patterns of nodal spread in stage III NSCLC: importance of EBUS-TBNA and 18F-FDG PET/CT for radiotherapy target volume definition

Purpose

The aim of this study was to compare the pattern of intra-patient spread of lymph-node (LN)-metastases within the mediastinum as assessed by ¹⁸F-FDG PET/CT and systematic endobronchial ultrasound-guided transbronchial-needle aspiration (EBUS-TBNA) for precise target volume definition in stage III NSCLC.

Methods

This is a single-center study based on our preceding investigation, including all consecutive patients with initial diagnosis of stage IIIA-C NSCLC, receiving concurrent radiochemotherapy (12/2011–06/2018). Inclusion criteria were curative treatment intent, ¹⁸F-FDG PET/CT and EBUS-TBNA prior to start of treatment. The lymphatic drainage was classified into echelon-1 (ipsilateral hilum), echelon-2 (ipsilateral LN-stations 4 and 7) and echelon-3 (rest of the mediastinum, contralateral hilum). The pattern of spread was classified according to all permutations of echelon-1, echelon-2, and echelon-3 EBUS-TBNA findings.

Results

In total, 180 patients were enrolled. Various patterns of LN-spread could be identified. Skip lesions with an involved echelon distal from an uninvolved one were detected in less than 10% of patients by both EBUS-TBNA and PET. The pattern with largest asymmetry was detected in cases with EBUS-TBNA- or PET-positivity at all three echelons (p < 0.0001, exact symmetry test). In a multivariable logistic model for EBUS-positivity at echelon-3, prognostic factors were PET-positivity at echelon-3 (Hazard ratio (HR) = 12.1; 95%-CI: 3.2–46.5), EBUS-TBNA positivity at echelon-2 (HR = 6.7; 95%-CI: 1.31–31.2) and left-sided tumor location (HR = 4.0; 95%-CI: 1.24–13.2). There were significantly less combined ipsilateral upper (LN-stations 2 and 4) and lower (LN-station 7) mediastinal involvements (16.8% of patients) with EBUS-TBNA than with PET (38.9%, p < 0.0001, exact symmetry test). EBUS-TBNA detected a lobe specific heterogeneity between the odds ratios of LN-positivity in the upper versus lower mediastinum (p = 0.0021, Breslow-Day test), while PET did not (p = 0.19).

Conclusion

Frequent patterns of LN-metastatic spread could be defined by EBUS-TBNA and PET and discrepancies in the pattern were seen between both methods. EBUS-TBNA showed more lobe and tumor laterality specific patterns of LN-metastases than PET and skipped lymph node stations were rare. These systematic relations offer the opportunity to further refine multi-parameter risk of LN-involvement models for target volume delineation based on pattern of spread by EBUS-TBNA and PET.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01904-4.