‘Minimally Invasive’ Biopsy Methods May Provide An Accurate Approach For Disease Staging in Patients With Suspected Lung Cancer

An evaluation of several endoscopic biopsy methods suggests that a “minimally invasive” approach may accurately determine the stage of suspected lung cancer, according to a study in the February 6 issue of JAMA.

Lung cancer is the most common cancer-related cause of death in the United States. Determining the stage of the disease is a critical factor regarding therapy and prognosis, according to background information in the article.

“Noninvasive staging with chest computed tomography (CT) or positron emission tomography (PET) is associated with high rates of false-positive and false-negative results, respectively. The American College of Chest Physicians recommends invasive staging with tissue confirmation of suspected metastatic mediastinal [center part of the thoracic cavity] lymph nodes. Mediastinoscopy or thoracoscopy [a surgical procedure that requires incisions] has been the diagnostic standard, but less invasive methods have emerged as potential alternatives,” the authors write.

Such methods include blind transbronchial needle aspiration (TBNA), endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), and, more recently, endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA).

Michael B. Wallace, M.D., M.P.H., of Mayo Clinic, Jacksonville, Fla., and colleagues compared the diagnostic accuracy of these three methods (and their combinations). Among 138 patients with suspected lung cancer who met all study criteria, 42 (30 percent) had malignant lymph nodes.

The researchers found that EBUS-FNA had higher sensitivity than TBNA (69 percent vs. 36 percent), detecting 29 (vs. 15) of the 42 malignant lymph nodes. EUS plus EBUS had higher estimated sensitivity (93 percent [39/42]) than any of the other methods. Compared with either EUS-FNA or EBUS-FNA alone, the combination identified 10 more malignant lymph nodes, with sensitivity estimated to be 24 percent higher than either approach alone.

The percentage of malignant lymph nodes detected by each procedure (number malignant/total number sampled) was 15 percent for TBNA, 19.7 percent for EBUS-FNA, and 22 percent for EUS-FNA. EUS plus EBUS also had higher sensitivity for detecting lymph nodes in any mediastinal location and for patients without lymph node enlargement on chest CT.

“If mediastinoscopy had been performed only when results from EUS plus EBUS were negative, this surgical procedure would have been avoided in 28 percent (39/138) of patients in this study. If EUS plus EBUS had been used to completely replace mediastinoscopy (100 percent of patients), 97 percent would have been correctly labeled as negative,” the authors write.

“If these data are confirmed by other studies, they thus suggest that EUS plus EBUS may be an alternative method for surgical staging of the mediastinum in patients with suspected lung cancer.”

JAMA. 2008; 299[5]:540-546.