ENDOBROCHIAL US FOR NSCLC

CHICAGO — Radial probe endobronchial ultrasound (EBUS) is safe and represents an improvement over conventional biopsy methods, a new study suggests. It significantly increases the diagnostic yield of pulmonary node biopsy when compared with conventional methods.

"Pulmonary nodes can be identified using a conventional CT [computed tomography] scan as a reference and radial probe EBUS to confirm," reiterated Alexander Chen, MD, assistant professor of medicine at the Washington University School of Medicine in St. Louis, Missouri, to Medical Medscape News. Dr. Chen is an Alfred Soffer Research Award semifinalist at CHEST 2013.

The advent of lung cancer screening for high-risk patients will bring with it increased detection of peripheral pulmonary nodules. Dr. Chen began his talk by explaining that conventional bronchoscopic lung biopsy is used to biopsy these nodules but has performed poorly for the diagnosis of peripheral pulmonary lesions. New technologies such as radial probe EBUS have improved the diagnostic yield of bronchoscopy for peripheral lesions.

During radial probe EBUS, ultrasound is used to guide biopsy during peripheral bronchoscopy. The ultrasound provides real-time confirmation of target lesion localization and therefore improves identification of peripheral pulmonary nodules.

Although radial probe EBUS has been available for a decade, it remains highly underused as a tool for peripheral bronchoscopy. In this study, Dr. Chen sought to compare radial probe EBUS with conventional bronchoscopic lung biopsy.

Dr. Chen retrospectively reviewed 467 cases that involved use of radial probe EBUS. While 496 cases of peripheral bronchoscopy were screened, the study included the 467 cases that used only radical probe EBUS for diagnostic purposes. Biopsies were performed between January 1, 2008, and December 31, 2012, in a tertiary care university hospital.

Nodules were categorized by size, and fluoroscopy was used on every single case. Radial EBUS views were classified as "concentric" when the probe was surrounded by lesion or "eccentric" when lesion was adjacent to the probe.

Dr. Chen evaluated the diagnostic yield of radial probe EBUS for peripheral pulmonary lesions, including the ability of the probe to locate peripheral lesions. He also reported on the influence of radial probe position.

Dr. Chen reported a 69% overall diagnostic yield with 96% of all nodules successfully identified by using radial probe EBUS. There was a 2.8% complication of pneumothorax, with a chest tube required in 1.5% of cases.

Table. Diagnosis by Nodule Size

Size (cm)	Diagnosis, n/n (%)
1-2	83/144 (58)
2.1-3	99/137 (72)
3.1-4	54/70 (77)
4.1-5	41/47 (87)
>5.1	35/40 (88)
All	321/467 (69)

Dr. Chen noted discordance between the ability to locate peripheral lesions and the ability to obtain diagnostic material. This was because the radial probe position relative to the target lesion significantly influenced diagnostic yield. He suggested that smaller-caliber bronchoscopes may be as effective as techniques that use a guide sheath.

Asked for comment, Nicholas S. Stollenwerk, MD, assistant professor at University of California, Davis, and comoderator of the session, told Medscape Medical that this report was "a very well done study on a very important problem for doctors. It's real-time visualization — very impressive."

"This will be the largest study to date on a big controversial issue," said Lonny B. Yarmus, DO, assistant professor of medicine at Johns Hopkins University in Baltimore, Maryland.

The audience was equally enthusiastic, with one member calling it a "great talk — nice big series."

Dr. Chen has a consulting honorarium from Olympus. Neither Dr. Stollenwerk nor Dr. Yarmus has disclosed any relevant financial relationships.

CHEST 2013. Presented October 27, 2013.