Some members had previously asked about a breath test to detect lung cancer, and at the time I was not familiar with this work. But research has been ongoing with a new test designed by Menssana Research to detect lung cancer (LC) by noting a pattern of volatile organic compounds (VOCs), essentially chemicals in exhaled breath, that characterizes people with lung cancer but isn’t seen in other people (recent summary papers here and here). In fact, VOCs are present in the air around us, and in the exhaled breath of people who don’t have cancer, but the technique used by the company involves using a complex computer analysis to detect patterns of VOC concentrations that are common to LC patients but not seen in people without cancer. Here’s the summary of their hypothesis for this work:
The test itself is simple, just involving a subject breathing for two minutes into a tube connected to a machine that collects these VOCs, and at the same time collecting a sample from the background air (which has its own VOC pattern, subtracted from the patient’s result). The pattern is analyzed, and if the result is “positive”, it corresponds to an approximately 81% likelihood of a person having lung cancer, and a negative result appears to rule out lung cancer approximately 85% of the time. This is in the same ballpark as in some CT scan studies of LC screening.
Interestingly, the results weren’t affected by cigarette smoking, and results weren’t more likely to be positive in patients with bulkier or more advanced disease than in patients with early stage disease. Importantly as well, LC patients who had undergone surgery continued to show a positive test, indicating that this isn’t an effective means of detecting recurrence, and also that whatever makes the test positive isn’t the tumor itself (and suggests to me that it may detect a very high risk setting in patients who test positive on the breath test but show no evidence of disease on scans).
This work remains investigational, and my center is participating in a breath test study, along with several centers in NYC and a few other places on the east coast, in which the test is being done on all sorts of patients to assess how well it discriminates in a larger population:
1) asymptomatic high risk patients (smokers, 50 and older)
2) high risk patients getting evaluated for a lung problem like cough or shortness of breath who haven’t been diagnosed with LC
3) patients with a tissue diagnosis of lung cancer (including resected or otherwise treated) or another lung problem like emphysema or pulmonary infection (I’m not sure why they’re lumping these patients with LC patients)
4) asymptomatic patients, not high risk, without significant medical problems
You can learn details about this study here.
Given the potential issues with CT screening, particularly the risk of false positives that can lead to anything from lots of anxiety to unnecessary invasive procedures, having the ability to add a level of confidence about a nodule being the real deal or more likely something unrelated to cancer would be a major step forward. Menssana is interested in using the breath test to help identify a group of patients who would be the highest yield to screen with CT, and I agree that the two studies together, in either order, could address many of the problems of each alone. I’ll be very interested in seeing the further development of this technology.