Lung cancer breath test looking more promising

Date: Jun-05-2014A study presented at a scientific meeting suggests we are getting closer to having a

reliable, non-invasive breath test for lung cancer. Led by the University of Colorado Cancer

Center in Denver, the study shows how a device that uses a gold nanoparticle sensor can not only

tell whether exhaled breath has come from a patient with COPD or lung cancer, but it can also

sense whether the cancer is in early or advanced stages.

The study is the work of Fred R. Hirsch, professor of medical oncology at the University of

Colorado School of Medicine, and colleagues, and was presented at the 50th Annual Meeting of the

American Society for Clinical Oncology (ASCO) in Chicago, IL.

Prof. Hirsch says a breath test for lung cancer could "totally revolutionize lung cancer

screening and diagnosis. The perspective here is the development of a non-traumatic, easy, cheap

approach to early detection and differentiation of lung cancer."

This is not the first time that the promise of a breath test for lung cancer, and other

cancers, has hit the headlines. For example, as far back as 2007, Medical News Today

reported a prototype breath test for

lung cancer that used a colorimetric sensor array to analyze the chemical fingerprint of

exhaled breath.

And more recently, in 2013, news came of a nanosensor test for stomach cancer

developed by some of the same researchers involved in this latest study.

Considerable challenge to overcome is generation of false positives

However, there is a big difference between showing that the method is feasible, and whether it

will work in clinical settings.

The metabolism of people with lung cancer is different to that of healthy people, and this is reflected in the chemical signature of their breath. Researchers say we are closer to a breath test for lung cancer.

For example, in the prototype tested in 2007, there was a high

rate of false positives - the test also picked out people without lung cancer. It is also

important that the test distinguishes between cancer and other conditions, which is what this

latest study undertakes to do.

Prof. Hirsch says there is a need for improved screening and diagnostic tools for lung cancer,

following the release of new lung

cancer screening guidelines from the US Preventive Task Force. They showed that screening via

low-dose computed tomography can reduce disease mortality by 20%.

He explains that the metabolism of people with lung cancer is different to that of healthy

people and this is reflected in the chemical signature of their breath. Thus, it should be possible

to differentiate among people with lung cancer, healthy subjects and also those with other lung

conditions like chronic obstructive pulmonary disease (COPD).

However, he points out that the challenge to tool developers is that the more sensitive you try

to make the screening tool, the higher the chance that you will pick up false positives. In the

case of lung cancer, this is detecting non-cancerous lung nodules, as he explains:

"You detect many, many nodules in those screenings and unfortunately, around 90% of them

are benign. So you need to find out how to better distinguish malignant from benign modules. The

goal of this tool is to use breath biomarkers to distinguish malignant from benign screen-detected

nodules."

Nanosensor distinguished among COPD, advanced and early lung cancer

The device that they tested requires subjects to blow up a balloon that is then connected to a

very sensitive gold nanoparticle sensor that traps and analyzes the volatile organic compounds

(VOCs) in the exhaled breath sample. The team that developed the device includes researchers from

the University of Colorado Cancer Center working with the Nobel-Prize-winning Technion University

in Haifa, Israel.

The study enrolled 358 patients in Israel, Denver and Florida. Of them, 213 were lung cancer

patients, including 62 with early stage and 143 with advanced stage disease. The other 145

patients did not have cancer.

A preliminary analysis of 80 lung cancer patients (64 with advanced stage) and 31 patients with

COPD, showed that the nanosensor array distinguished significantly between COPD and lung cancer

(accuracy of 85%), COPD and advanced lung cancer (accuracy of 82%), and early and advanced lung

cancer (accuracy of 79%).

Prof. Hirsch sees the device going further than initial screening or diagnosis. For instance,

it could measure changes in patients' breath signatures over time to see how well they respond to

treatment. They are already working on such an application at the Cancer Center.

Another possibility is to make a simple, cheap and rapid test that helps doctors identify a

patient's lung cancer subtype to ensure earlier and faster selection of appropriate targeted

therapy.

He pictures a future possible scenario: "imagine standing in the grocery store and having high

risk people blow into a balloon or a USB device, and the profile of the organic compounds in their

breath would tell you if they are at risk for developing or having lung cancer, which then could

lead to further, focused tests."

Written by Catharine Paddock PhD

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.