KEYSTONE, COLO. — Management of a solitary pulmonary nodule 1 cm or less in size in a patient at intermediate risk for lung cancer remains an enormous challenge and considerable burden on the health care system.
“This is where all the money is,” Dr. Ali I. Musani observed at a meeting on allergy and respiratory diseases.
More than 150,000 patients per year in the United States present to physicians with a solitary pulmonary nodule (SPN). It's an incidental finding on 1 in 500 chest x-rays. The prevalence of an SPN on a screening CT in individuals at increased risk for lung cancer because of smoking history or occupational exposure is 13%.
In deciding what to do about these lesions, size matters.
“If a nodule is more than 1 cm and up to 2 cm, that's the ideal size for me, because that's where all my sampling technologies come into play. If a nodule is 1 cm or less, we still don't have very good technologies to biopsy them. If you start taking all these out, even in the high-risk population, the vast majority are going to be benign. So if they're worried, take it out; otherwise, follow by CT scan,” said Dr. Musani, director of interventional pulmonology at National Jewish Health.
The standard recommendation for follow-up is 2 years of watchful waiting with CT every 6 months, looking for the lesion growth that would trigger a biopsy. When Dr. Musani is concerned about the possibility of bronchoalveolar carcinoma, however, that recommendation goes out the window.
“In recent years bronchoalveolar carcinoma has become very, very common. These cancers grow very slowly; 2 years of stability really means nothing. So if I see features of bronchoalveolar carcinoma on the CT, I don't care about the American College of Chest Physicians or American Thoracic Society recommendations, I keep doing CTs for 4 or 5 years,” he said at the meeting, which was sponsored by the National Jewish Medical and Research Center.
A key problem is the lack of an established screening tool for lung cancer, despite the readily identifiable risk factors for the malignancy. More than three-quarters of lung cancers are diagnosed at stage III or IV, with a 5-year survival rate of only 15%. In contrast, lung cancers diagnosed at stage I have an 88% 10-year survival rate, so early diagnosis with the help of screening CT offers great hope.
CT is reliable for localizing and characterizing a lung lesion, but a biopsy is still essential for diagnosis. A variety of tools is available for this purpose, including transthoracic needle aspiration (TTNA), standard bronchoscopy, sputum cytology, and surgical biopsy. Each has its disadvantages.
The most exciting diagnostic development of late is electromagnetic navigation bronchoscopy.
This proprietary technology, marketed by superDimension Inc., utilizes a $20,000 software package to convert a high-resolution CT into a three-dimensional road map for real-time navigation using a steerable endoscopic catheter guided by GPS-like technology while the patient lies in an electromagnetic field. This provides minimally invasive access to SPNs located deep in the lungs, well beyond the reach of standard bronchoscopy. Once at the target, biopsy needles and forceps are passed through the catheter channel.
Dr. Musani's personal experience with the superDimension i-Logic electronic navigation bronchoscopy system has been quite favorable.
“I want to see data on 1- to 2-cm lesions. That's the real challenge,” the pulmonologist noted.
Dr. Musani disclosed serving on the speakers bureaus for Cardinal Health, Olympus, and superDimension.
iLogic provides a three-dimensional road map for real-time navigation using a steerable endoscopic catheter guided by GPS-like technology.
Source Images courtesy superDimension, Inc