The continuing evolution of lung cancer screening has created a need for new approaches to managing lung nodules. At the same time, new technologies such as serum biomarkers and robotic bronchoscopy offer the potential for improved diagnosis.
Bronchoscopy is also a potential vehicle to deliver ablative therapies that are now delivered percutaneously, but the potential is clouded by the low diagnostic yields of even the most advanced bronchoscopic procedures.
Presenters addressed these clinical controversies in the session Clinical Controversies in Lung Nodule Management: Rapid Fire on Tuesday.
Yields have varied over time and peaked at around 50% in 2015, said Kevin Haas, MD, assistant professor of clinical medicine at the University of Illinois. More recent yields have generally been lower. Recent data also suggest that standard bronchoscopy, with its multiple biopsy sites, may outperform endobronchial ultrasound (EBUS) with navigation.
“Sometimes, the airway system leads right to the lesion,” said Alexander Chen, MD, associate professor of medicine and surgery at Washington University School of Medicine. “And sometimes, the lesion is off to the side of the airway and easy to miss with more tightly focused techniques.”
Improvements in navigation might improve yields. So might robotic bronchoscopy. Robotic systems are no smaller than standard scopes, but design factors allow them to penetrate at least two generations lower into the airway and reach the pleura. The robotic scope has a stiff sheath that prevents it from prolapsing into the air space the way conventional scopes tend to do.
“Robotics give us the opportunity to rebuild the bronchoscope just the way we want it,” Dr. Chen said. “We can tie in some of the more promising tools and techniques we are developing.”
But don’t hold your breath for a robotic bronchoscope. The device works well in cadaver models. It works well in humans, too, with a 96% yield in a proof of concept trial.
“What we need now is a randomized controlled trial,” Dr. Chen said. “And it has to be powered to demonstrate superiority to some other procedure that we already use.”
There is also the possibility that serum biomarkers could help focus bronchoscopy to patients who are most likely to benefit from biopsy. Most patients with lung nodules are on a spectrum of probability of cancer, explained Gerard Silvestri, MD, MS, professor of medicine at the Medical University of South Carolina.
If the likelihood of cancer is less than 5%, surveillance is appropriate. If the likelihood of cancer is greater than 65%, treatment, usually surgery, is the appropriate option. Everyone in between needs a biopsy.
“There is a clear need for better testing,” Dr. Silvestri said. “You don’t want to do a procedure on a patient who doesn’t have disease. And you don’t want to miss cancer.”
Biomarkers, particularly something easy to obtain, such as a serum biomarker, could help. Rule out biomarkers, downgrade patients from surgery to biopsy. Rule in biomarkers, upgrade from surveillance to biopsy. Either way, a biopsy is appropriate.
Bronchoscopy is also venturing into treatment for early stage cancers. Multiple technologies are currently used percutaneously, including radio frequency ablation (RFA), microwave ablation (MWA), and cryotherapy. Brachytherapy is another potential treatment, though it is seldom used in current lung practice, noted Momen Wahidi, MD, MBA, FCCP, associate professor of medicine at Duke University Hospital.
“The vision is a bronchoscopic biopsy, handing the specimen to the on-site pathology lab, which confirms an adenocarcinoma, which you immediately treat with a bronchoscopic device,” he said “Biopsy, diagnosis, and treatment in a single visit.”
Percutaneous ablation procedures are occasionally used in the lung, but pneumothorax is a problem. And treatment outcomes are not as robust as those seen in liver and other tissues.
An early trial of CT-guided bronchoscopic RFA in 10 patients showed 82% local disease control, Dr. Wahidi reported, and 61.5% 5-year survival. EBUS guided bronchoscopic RFA works in a swine model and is being tested in patients.
“The concept of the death of bronchoscopy is interesting, but we are not there,” said Lonny Yarmus, DO, MBA, clinical chief of pulmonary and critical care and associate professor of medicine at Johns Hopkins Hospital. “There will always be a place for bronchoscopy.”