This release discusses a study testing the efficacy of a test using the breath of lung cancer patients. Since patients with lung cancer are known to have specific chemicals in their breath — known as volatile organic compounds (VOCs) — which are caused by the disease, detecting them after the patients underwent surgery could indicate a recurrence of the disease. These chemicals are, in effect, markers for the presence of disease.
The release notes the study showed a reduction in the amount of these compounds after patients had undergone surgical resection of the lung, but doesn’t give any numerical information about the level of reduction, other than to say it is “significant.” The release provides a nice description of costs and describes the test’s potential benefit to reduce harm from repeat CTs.
Lung cancer is the leading cause of cancer death in the United States with 224,000 new diagnoses each year and 158,000 deaths, according to the American Cancer Society. Both early detection and successful monitoring of disease recurrence might reduce those numbers considerably.
Current monitoring for lung cancer recurrence after surgery is based on X-ray computed tomography (CT) scans. A breath test using chemical markers to detect recurrence could potentially be cheaper, simpler and less risky than repeat CT scans. However, it’s important to keep in mind that a positive breath test would still necessitate a follow-up CT scan and with almost every screening test, there is a risk of missed diagnosis.
The release does mention that the cost of materials to conduct the test is “around $20” which is considerably less than the cost of CT scan imaging which is now being used. It is unclear, however, how much patients would be actually charged. The release should’ve been clearer about the actual cost to patients.
The release provides a good narrative of the potential benefits of the breath test (lower cost, reduces exposure to repeat CT scans) but does not provide any quantification. The release notes that “The researchers found a significant decrease in overall carbonyl VOC levels following surgery; in fact, three of the four carbonyl VOCs normalized after surgery, matching levels of the control group.” We aren’t told what a “significant decrease” means or what a “normalized” level would be. The release would have been more complete if it had given us some idea of the test’s ability to accurately detect or rule out lung cancer recurrence.
The release points out that the test could potentially reduce harms by reducing a patient’s repeat exposure to radiation from CT scans. However, the harms of the test itself — i.e. false positive screens that cause substantial anxiety and necessitate additional testing — are not addressed.
As noted above under “Why This Matters,” the concern is that using this test to guide surveillance testing (whether to order the CT) could be a problem if the test is not actually very accurate when used in that role — false positive and particularly false negative results could lead to harms. We have no data (certainly not from the study in question) that could address these concerns.
All we know from the release is that VOC levels dropped after surgery and were comparable to levels in controls. The study provided no data on how well this test would perform for cancer surveillance — which would require prospectively evaluating the breath test against the standard CT tests to determine its predictive values. The news release might have more appropriately stated that the breath test is being evaluated as a tool to monitor for disease recurrence — not being used as a tool.
There’s no disease-mongering here.
The release earns a satisfactory here for providing both funding sources and pointing out that three of the seven researchers have ties to a medical equipment company which deals with breath analysis. The information, however, lies at the end of the story in a portion commonly referred to as “boilerplate” information, which readers often ignore. Incorporating such info into the body of the release better serves readers.
This release effectively points out that current practice uses periodic CT scans as the method of monitoring the potential recurrence of lung cancer in patients. It states that the breath analysis might be a substitute for the more expensive imaging procedure.
Early on the release states, “Now the test is being used to monitor for disease recurrence.” That sentence might confuse some readers into thinking the test is already in use. You have to read to the end to learn from a researcher’s quote that “Our next step is getting approval from the FDA.” So that’s a signal to readers that the test is not yet available, and may not be for some time. In addition, the comment about FDA approval doesn’t give us any sense of the hurdles/obstacles that remain before the test would be validated for clinical use.
The release doesn’t make a strong claim of novelty — and that’s appropriate.
A quick online search found that besides this research from the University of Louisville in Kentucky, at least two other institutions are developing breath tests for lung cancer detection: Georgia Institute of Technology and the Winship Cancer Institute of Emory University and the University of Leicester.
The release said “A subset of four VOCs—called carbonyl compounds because of their carbon base—have been discovered in the exhaled breath of lung cancer patients.” Discoveries sound novel. But this study, more than a decade old, describes the use of VOCs for lung cancer detection.
While the release doesn’t claim to be “first,” it might have mentioned related work that has been done in this field of research.
The release doesn’t use any unjustifiable or sensational language.