Hotter breath linked to lung cancer

MUNICH, Germany — A preliminary study of exhaled breath suggests that temperatures higher than 34°C may be a strong indicator of the presence of lung cancer. In a sample of 82 patients who presented with clinical suspicion of lung cancer, 96% of patients had the disease.

"Airway inflammation and angiogenesis play a key role in the pathogenesis of lung cancer," Giulia Scioscia, MD, a fellow in pulmonary medicine at Hospital Clínic i Provincial de Barcelona, said at a news conference here at the European Respiratory Society (ERS) International Congress 2014. "Exhaled breath temperature has been proven to be an indicator of airway inflammation and increased vascularity. The aim of our research is to determine possible correlations of exhaled breath with progression, metastasis or other clinical outcomes of patients with cancers."

The researchers aimed to find breath temperature values that correlate with lung cancer. They analyzed 82 consecutive participants with a radiologic suspicion of lung cancer using the X-Halo (Delmedica Investments) breath thermometer. Lung cancer was later diagnosed in 40 people. A total of 42 did not have lung cancer and served as controls. All patients underwent standard diagnostic and staging procedures.

The team compared breath temperatures in patients with lung cancer and controls in various categories, including by sex, age, smoking habit, and the presence or absence of chronic obstructive pulmonary disease. In each category, people with cancer had statistically significantly higher breath temperatures than controls.

The researchers then used a receiver operating characteristic curve to determine an ideal temperature threshold for signaling lung cancer. That analysis showed that values above 34°C would be a good cutoff. Most — 96% — who had breath temperatures in that range were found to have lung cancer.

Pilot Study
The researchers stressed that this was a pilot study. "It's not sensitive enough," coauthor Giovanna Elisiana Carpagnano, MD, from the University of Foggia in Italy, said at the news conference. However, Dr. Carpagnano added that it could eventually become part of a screening panel. The researchers plan to explore the test in patients with other inflammatory conditions to get a better idea of its performance.

"I think the data are quite interesting," chair of the ERS lung cancer group Fernando Gamarra, MD, from Klinikum St. Elisabeth Straubing in Germany said. It's also novel. "I'm not aware that anybody has done it before," he added. Dr. Gamarra said he thinks that the researchers will have to account for other factors that could affect breath temperature, such as whether the person is currently smoking, the velocity with which a person exhales, or overall size. Large people may have higher breath temperatures, he pointed out.

It also remains to be seen if the approach could work consistently in early-stage cancers, which is the population that would most benefit from screening. The current study drew from patients already presenting at a hospital, and so they tended to have more advanced disease, although the researchers did note higher temperatures even in early cancers. "I would like to see a study in a limited group, say just in patients with stage 1 or 2," Dr. Gamarra said.