Breath Analysis Offers Noninvasive Method to Detect Early Lung Cancer
Researchers at the University of Louisville School of Medicine are using breath analysis to detect the presence of lung cancer. Preliminary data indicate that this noninvasive tool offers the sensitivity of PET scanning and has almost twice the specificity of PET for distinguishing patients with benign lung disease from those with early-stage cancer. Michael Bousamra II, MD, Associate Professor in the Department of Cardiovascular and Thoracic Surgery, presented the results of the study at the American Association for Thoracic Surgery 2014 Annual Meeting on April 29, 2014.
A reliable, noninvasive diagnostic method imposes less physical and financial burden on patients who actually have no significant disease, while rapid and accurate diagnosis expedites treatment for patients who truly have lung cancer. According to the investigators, although the breath test would not replace CT as a primary screening tool, it would be particularly helpful in conjunction with a positive CT scan result.
Study Details
Investigators used specially coated silicon microchips to collect breath samples from 88 healthy controls, 107 patients with lung cancer, 40 individuals with benign pulmonary disease, and 7 with metastatic lung cancer.
Previous work had pinpointed four specific substances, known as carbonyl compounds, in breath samples as elevated cancer markers that distinguish patients with lung cancer from those with benign disease. The carbonyl compounds found in the breath are thought to reflect chemical reactions occurring in malignant lung tumors. In this study, the authors compared the findings from the breath analyses to the results from PET scans.
Similar Sensitivity, Higher Specificity
The investigators found that the sensitivity and specificity of breath analysis depended upon how many of the elevated cancer markers were elevated. For example, having three or four elevated cancer markers was diagnostic of lung cancer in 95% of those with this result. The majority of patients with benign pulmonary disease had either zero or one elevated cancer marker while those with stage IV cancer were most likely to have three or four. The number of elevated cancer markers could be used to differentiate benign disease from both early- and advanced-stage lung cancer. Interestingly, three of the four elevated markers returned to normal levels after cancer resection.
When it came to differentiating early-stage lung cancer from benign pulmonary disease, breath analysis and PET scanning had similar sensitivities (82.8% and 90.3%, respectively). However, breath analysis had a much higher specificity than PET (75% vs 38.7%, respectively) for distinguishing benign disease, which means that it was much more accurate at identifying those who did not have cancer. This would be an important feature for patients with benign disease, since having a breath analysis rather than PET scan could mean avoiding an unnecessary invasive biopsy procedure later on.
“This breath analysis method presents the potential for a cheaper and more reliable diagnostic option for patients found to have bulky disease on a CT scan. If the breath analysis is negative, the patient may, in some instances, be followed with repeated exams without necessitating a biopsy. But a positive breath analysis would indicate that the patient may proceed to definitive biopsy, thus expediting treatment,” said Dr. Bousamra.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
