From the Journals

Can lung cancer ID be as easy as breathing into an analyzer?


 

FROM ECLINICAL MEDICINE

A study published in May in The Lancet journal eClinicalMedicine reports that breathomics testing is one step closer to becoming a reality as a lung cancer screening tool.

The tool was successfully used to identify, in 84 patients, 16 lung cancer–related carcinogenic volatile compounds (VOCs), such as aldehydes, hydrocarbons, ketones, carboxylic acids, and furan – some of which are compounds used in the production of common household goods, such as furniture, carpeting, and wood floors.

“The test is anticipated to be highlighted for primary screening of lung cancer but not the final diagnosis,” according to study authors who were led by Peiyu Wang, MD, PhD, chair of social medicine and health at Peking (China) University.

While early diagnosis and treatment are critical for improving lung cancer survival, early detection of lung cancer is challenging because of the lack of clinical manifestations and specific biomarkers. Annual CT scans are costly and include radiation exposure, Dr. Wang and his associates wrote.

Breathomics testing is considered a promising method for detection and screening for lung cancer. It has been under study for years and in 2014, researchers from Belgium published a review in Cancer Epidemiology Biomarkers and Prevention documenting the use of VOCs as early diagnostic or prognostic biomarkers for mesothelioma.

Lung cancer breath biomarkers identified in various studies have been highly heterogeneous because of differing sample collection methods, varying patient conditions, testing environments, and analysis methods. As a result, there currently is no breathomics test for lung cancer screening, Dr. Wang said in an interview.

In terms of its potential as a lung cancer screening tool, “Clinicians may introduce this test for people with high risk for lung cancer, such as elderly smokers, or people with suspected symptoms. It may also be introduced for young populations with subjective or objective needs to screen for lung cancer. As the proportion of lung adenocarcinoma in nonsmoking young women is increasing, the test may be a good method for lung cancer screening in this population,” Dr. Wang said.

After adjusting for age, sex, smoking, and comorbidities, researchers found elevated levels for 16 VOCs in patients with lung cancer. A diagnostic model including the 16 VOCs achieved an area under the curve of 0.952, sensitivity of 89.2%, specificity of 89.1%, and accuracy of 89.1% in lung cancer diagnosis. A model including the top eight VOCs achieved an area under the curve of 0.931, sensitivity of 86.0%, specificity of 87.2%, and accuracy of 86.9%.

After selecting 28 VOCs as candidates through a literature review, Dr. Wang and associates conducted a prospective discovery study from Sept. 1 to Dec. 31, 2020, using high-pressure photon ionization time-of-flight mass spectrometry to evaluate their performance for lung cancer diagnosis. The validation study included 157 lung cancer patients (mean age 57.0 years; 54.1 percent female) and 368 volunteers (mean age 44.5 years; 31.3% female).

“The external validation confirmed good performance of these biomarkers in lung cancer detection,” the researchers stated. It helped, they added, to solve the heterogeneity among published studies, establishing both 16 VOCs and 8 VOCS for lung cancer screening.

The authors stated that a large gap exists between breathomics research and clinical practices in lung cancer detection and screening. While the validated 16 VOCs, mainly aldehydes and hydrocarbon, showed potential for promoting this lung cancer screening strategy, more scientific studies are warranted to investigate the underlying mechanisms of identified lung cancer VOCs.

Dr. Wang declared no competing interests.

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