A single breath test can screen for lung cancer and also detect its recurrence after tumor removal, according to a study posted online June 9, 2016 in the Annals of Thoracic Surgery. If validated, the breath test would be significantly less expensive and easier to administer than current lung cancer detection methods.
In earlier work, the investigators identified a “signature” of certain volatile organic compounds—specifically, four exhaled carbonyl compounds—in the breath of patients with lung cancer. Results from that research showed the breath test was 83% sensitive and 74% specific for detecting early-stage disease.
In this study, the researchers investigated whether the breath test could identify disease recurrence after surgical resection of lung cancer tumors. To find out, the researchers collected breath samples from 31 lung cancer patients before and after surgery, and compared their carbonyl compound levels with samples from 187 healthy patients with no known lung disease.
After surgical resection in the lung cancer patients, their measures of all four carbonyl compounds were significantly lower, and three of the four compounds were at the same levels as those of the control subjects.
“The rapid normalization of almost all of the four compounds after surgery provides strong evidence that they are directly produced by the tumor environment,” said Erin M. Schumer, MD, MPH, of the Department of Cardiovascular and Thoracic Surgery at University of Louisville (U of L) School of Medicine, in Louisville, KY. “This study confirms that the technology is accurate.”
The researchers acknowledged that they don’t yet understand the mechanism underlying the elevation of these compounds, nor can the test yet distinguish between such cancers as adenocarcinoma and squamous cell carcinoma.
Regardless, the researchers contend that using the breath test for monitoring patients would be easier and more accessible than the current recommended method of low-dose CT scanning, which can be inconvenient, expensive, and expose the patient to radiation.
“The [breath] test itself is cheap. It is around $30,” Dr. Schumer said.
To perform the simple test, the patient makes a single exhalation of breath (about 1L) into a Tedlar bag. The sample is then pumped out over a silicon microchip, which reacts to the carbonyl compounds. The chip is then analyzed by mass spectrometry for its carbonyl levels.
“The great potential with breath analysis is detecting lung cancer at any point, both as a primary screening tool and to follow patients after disease has been treated,” said Victor van Berkel, MD, PhD, Assistant Professor of Surgery in U of L’s Department of Cardiovascular and Thoracic Surgery. “The technology is pretty robust. Our next step is getting approval from the FDA.”
Dr. van Berkel and two other authors disclosed that they are founders of Breath Diagnostics. Dr. Schumer and the remaining authors declared no conflicts of interest.