Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX; Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Mexico.
Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX.
Chest. 2021 Apr;159(4):1642-1651. doi: 10.1016/j.chest.2020.10.041. Epub 2020 Oct 23.
Systematic endobronchial ultrasound (EBUS)-guided lung cancer staging starts with hilar N3 nodes, proceeding sequentially to mediastinal N3, N2, and N1 nodes, with sampling of all enlarged nodes (size, ≥ 5 mm) by EBUS. However, procedure time is limited by patient comfort when moderate sedation is used. It is unclear if EBUS staging should start with hilar N3 nodes or whether starting with mediastinal N3 nodes suffices. Knowing the probability of hilar N3 nodes with PET-CT scan negative findings harboring occult metastasis can inform this decision.
What proportion of patients with hilar N3 nodes showing negative PET-CT scan findings have malignancy by EBUS?
This retrospective observational, single-center cohort study included consecutive patients with clinical-radiographic T1-3, N0-3, M0 non-small cell lung cancer undergoing systematic EBUS staging with biopsy of hilar N3 nodes with negative PET-CT scan findings. The primary outcome was the proportion of patients with malignant hilar N3 nodes showing negative PET-CT scan findings. Based on expert opinion, a threshold probability of malignancy of less than 5% was considered sufficient to skip hilar N3 nodes. We used the binomial exact test to compare the observed proportion vs threshold probability of 5%.
Of 1,737 consecutive patients undergoing EBUS staging, 1,567 showed negative PET-CT scan findings of the hilar N3 nodes. These nodes were enlarged by EBUS and were sampled in 739 patients. Malignancy was found in the hilar N3 nodes of 5 of 739 patients (0.68%; 95% CI, 0.22%-1.57%). The proportion was significantly less than the threshold probability (P < .001). Patients with positive PET scan results of the mediastinal N3 nodes were at higher risk of having occult hilar N3 nodal metastasis (P = .003), found in 3 of 46 patients (6.5%; 95% CI, 1.4%-17.9%) with positive PET scan results of the mediastinal N3 nodes.
When using moderate sedation, because time is limited, it is reasonable to start with the mediastinal N3 nodes if the hilar and mediastinal N3 nodes show negative PET scan results. Patients with positive PET scan findings of the mediastinal N3 nodes probably should undergo hilar N3 node sampling.
系统性支气管内超声（EBUS）引导下肺癌分期从肺门 N3 淋巴结开始，依次进行纵隔 N3、N2 和 N1 淋巴结，对所有肿大的淋巴结（大小，≥5mm）进行 EBUS 取样。然而，当使用中度镇静时，患者的舒适度限制了操作时间。目前尚不清楚 EBUS 分期是否应该从肺门 N3 淋巴结开始，或者仅从纵隔 N3 淋巴结开始是否足够。了解 PET-CT 扫描阴性发现的肺门 N3 淋巴结中隐匿性转移的概率可以为这一决策提供信息。
PET-CT 扫描阴性发现的肺门 N3 淋巴结中，有多少比例的患者存在恶性肿瘤？
本回顾性观察性、单中心队列研究纳入了连续的临床-影像学 T1-3、N0-3、M0 非小细胞肺癌患者，这些患者接受了系统的 EBUS 分期，对 PET-CT 扫描阴性发现的肺门 N3 淋巴结进行了活检。主要结局是肺门 N3 淋巴结显示阴性 PET-CT 扫描结果的患者中恶性肿瘤的比例。根据专家意见，认为恶性肿瘤的概率低于 5%就足以跳过肺门 N3 淋巴结。我们使用二项精确检验比较了观察到的比例与 5%的阈值概率。
在 1737 例连续接受 EBUS 分期的患者中，1567 例患者的肺门 N3 淋巴结 PET-CT 扫描结果为阴性。这些淋巴结通过 EBUS 增大，并在 739 例患者中进行了取样。在 739 例患者中有 5 例（0.68%；95%CI，0.22%-1.57%）在肺门 N3 淋巴结中发现了恶性肿瘤。这一比例明显低于阈值概率（P<0.001）。纵隔 N3 淋巴结 PET 扫描结果阳性的患者存在隐匿性肺门 N3 淋巴结转移的风险更高（P=0.003），在 46 例纵隔 N3 淋巴结 PET 扫描结果阳性的患者中有 3 例（6.5%；95%CI，1.4%-17.9%）发现了这种转移。
当使用中度镇静时，由于时间有限，如果肺门和纵隔 N3 淋巴结的 PET 扫描结果均为阴性，那么从纵隔 N3 淋巴结开始是合理的。纵隔 N3 淋巴结 PET 扫描结果阳性的患者可能需要进行肺门 N3 淋巴结取样。
