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Abstract

We greatly appreciate the thoughtful comments offered by Drs Roy and Fortin regarding our recently published manuscript,1DuComb E.A. Tonelli B.A. Tuo Y. et al.Evidence for expanding invasive mediastinal staging for peripheral T1 lung tumors.Chest. 2020; 158: 2192-2199Abstract Full Text Full Text PDF Scopus (6) Google Scholar particularly given their work in this area. We concur with our colleagues that the prevalence of nodal disease in the population can impact the performance of any diagnostic test. It is therefore imperative to evaluate aggregate data, because that from any single-study data may be misleading. The sensitivity of PET-CT for noninvasive staging of the mediastinum, derived from 19 different studies, was found to be only 62% as aggregated by the American College of Chest Physicians (CHEST) guideline group.2Silvestri G.A. Gonzalez A.V. Jantz M.A. et al.Methods for staging non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines.Chest. 2013; 143: e211S-e250SAbstract Full Text Full Text PDF PubMed Scopus (950) Google Scholar Because of the perceived low risk of mediastinal metastasis from a peripheral cT1 lesion, the CHEST guidelines do not require a PET scan for those with peripheral stage cIA tumors. In the United States, PET-CT is also often not covered by insurance before tissue biopsy. Thus, patients in the National Lung Screening Trial, and many patients currently in the United States, with screen-detected peripheral cT1 lung cancers would not undergo PET-CT at all, and almost certainly not before bronchoscopic biopsy. The same CHEST guideline also includes an analysis of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) performance for identification of mediastinal metastasis. The aggregate sensitivity of EBUS-TBNA for mediastinal metastasis was 89%, and it was identical between the 22 studies that included cN1-N3 disease and the four that included patients with a radiologically normal mediastinum (cN0). We also agree that one must weigh the risks and benefits when considering whether to perform invasive staging. In our view, an 8% risk of incorrect staging and undertreatment of a potentially lethal malignancy outweighs the <1% risk of a complication from EBUS-TBNA.3Eapen G.A. Shah A.M. Lei X. et al.Complications, consequences, and practice patterns of endobronchial ultrasound-guided transbronchial needle aspiration: results of the AQuIRE registry.Chest. 2013; 143: 1044-1053Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar In our study, not only was there an increased risk of N2 disease, but over 5% of all lymph node metastases were to an N3 site, which greatly changes management.1DuComb E.A. Tonelli B.A. Tuo Y. et al.Evidence for expanding invasive mediastinal staging for peripheral T1 lung tumors.Chest. 2020; 158: 2192-2199Abstract Full Text Full Text PDF Scopus (6) Google Scholar For those with N2 disease, multiple studies have reported worse overall outcomes for stage IIIA patients who undergo primary resection vs those who undergo preoperative induction therapy.4Ramnath N. Dilling T.J. Harris L.J. et al.Treatment of stage III non-small cell lung cancer: diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines.Chest. 2013; 143: e314S-e340SAbstract Full Text Full Text PDF PubMed Scopus (334) Google Scholar Additionally, nonoperative patients with unrecognized N2 disease may inappropriately receive only definitive radiation therapy. As we advance our capabilities to diagnose and treat lung cancer, we must be forward thinking about the importance of accurate mediastinal staging. There are currently more than 100 active trials of neoadjuvant therapy for lung cancer. The clinical application of novel neoadjuvant therapies will require precise staging of disease. We concur with the reviewers that the central vs peripheral definition of T1 lung tumors is irrelevant for determining the risk of mediastinal metastasis. We would argue that thorough mediastinal staging would include invasive staging for all cT1 tumors. Evidence for Expanding Invasive Mediastinal Staging for Peripheral T1 Lung TumorsCHESTVol. 158Issue 5PreviewOur data indicate a high rate of N2 metastasis among T1 tumors and no significant relationship between tumor diameter or location. This suggests that patients with small, peripheral lung cancers may benefit from invasive mediastinal staging. Full-Text PDF Should We Expand Invasive Mediastinal Staging to Peripheral T1 Lung Tumors?CHESTVol. 159Issue 1PreviewWe read with great interest the DuComb et al1 article in CHEST (May 2020) on the impact of tumor location on radiologically occult mediastinal disease (OMD) in screening-detected cT1N0M0 non-small cell lung cancers (NSCLC) from the National Lung Screening Trial. They measured X, Y, and Z coordinates from the main carina to evaluate the centrality of tumors and found no association between tumor location and risk of N2/N3 disease. We congratulate them for their novel objective method but would like to discuss further their conclusions. Full-Text PDF