Less Invasive Way to Stage Lung Cancer Shows Promise
TUESDAY Feb. 5, 2008 -- Less invasive approaches for determining how far lung cancer has spread may be better than traditional, invasive procedures.
Although the finding, published in the Feb. 6 issue of the Journal of the American Medical Association, needs to be confirmed, it may point to a new era for people with lung cancer or suspected lung cancer.
"Currently, most patients in the U.S. who have lung cancers get a surgical procedure to determine if the cancer has spread to the lymph nodes," explained study author Dr. Michael Wallace, a professor of medicine at the Mayo Clinic College of Medicine in Jacksonville, Fla. "This study suggests that a less invasive set of procedures are highly accurate and less invasive than surgical procedures, and therefore might be an alternative."
Lung cancer is the number one cancer killer in the United States. While early detection is key, proper staging, which primarily involves determining if the malignancy has spread to the lymph nodes, is important for therapy and prognosis.
For people whose cancer is still confined to the lungs and certain lymph nodes, surgery is the recommended treatment. But the benefit of surgery is less clear for patients whose cancer has spread further.
"If the cancer has already spread to the lymph nodes in the middle of chest, you can't cure it [with surgery], so it's very important to know if it has spread to those lymph nodes," explained Norman Edelman, chief medical officer for the American Lung Association. "This so-called mediastinoscopy [which requires general anesthesia] is considered the gold standard although . . . there are some nodes that are hard to get this way."
"Could this replace mediastinoscopy? Yes, it could, but right now the doctors would have to make a judgment," added Edelman. "We don't have the absolute final answer, but it's promising."
Edelman pointed out, however, that the minimally invasive techniques described in this paper may not be available in many local hospitals.
Current noninvasive techniques such as computed tomography (CT) or positron emission tomography (PET) have high false-positive and false-negative results, respectively.
This study compared the accuracy of three different minimally invasive methods of staging and combinations thereof: traditional transbronchial needle aspiration (TBNA), endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA), and transesophageal endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA).
"These procedures are endoscopic, meaning there's no cutting involved through the skin, and they're done as outpatients under twilight sedation," Wallace explained. "Individuals come in and go home on the same day. Essentially, there is no recovery other than just letting the sedation wear off."
A total of 138 patients with suspected lung cancer were involved; 30 percent had malignant lymph nodes.
EBUS-FNA was more sensitive (meaning it picked up more malignancies) than TBNA, detecting 69 percent of malignant lymph nodes versus 36 percent.
The combination of EBUS-FNA and EUS-FNA had 93 percent estimated sensitivity and a 97 percent negative predictive value (proportion of patients with negative results who are actually negative), compared with either method used alone.
The combination, which had both higher sensitivity and higher negative predictive value, may be a substitute for current, invasive techniques, the authors stated.
If mediastinoscopy had been done only when the combination results were negative, the more invasive surgical procedure would have been avoided in 28 percent of patients, the study showed.
If the combination had completely replaced mediastinoscopy, 97 percent would have been correctly labeled as negative.
"It is really focused on less invasive ways to stage the cancers as opposed to earlier detection methods, but it allows us to better select patients who will benefit from surgery to do it in a less invasive way and, importantly, to avoid surgical procedures in patients where the tumor has already spread who wouldn't benefit from the surgery," Wallace said.
Wallace reported that he had received research grants from different makers of equipment relevant to endoscopic ultrasound.
The American Lung Association has more on lung cancer.
Posted: February 2008
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