Technique breathes new life into gastric cancer diagnosis

Mar 7 2013

A nanomaterial breath test can accurately distinguish gastric cancer from benign stomach disorders, preliminary results show.

The technique could offer an alternative to the current diagnostic standard of endoscopy which is limited by its invasiveness and poor availability.

"If found to be accurate enough the nanomaterial breath test presents a new possibility for screening a population for stomach cancer, which would hopefully lead to earlier diagnosis of the disease," said author Hossam Haick (Technion - Israel Institute of Technology, Haifa) in a press statement.

The researchers used breath samples from 130 patients with gastric complaints who had been diagnosed with gastric cancer (n=37), benign gastric ulcers (n=32), or less severe gastric conditions (n=61).

They analyzed the breath samples with an array of 14 nanomaterial-based VOC sensors to develop a "breath print" for gastric cancer.

The authors found that the nanomaterial-based sensors could not only distinguish gastric cancer from less severe conditions, but also determine the stage of the cancer.

The sensor was able to distinguish gastric cancer from benign conditions with a sensitivity of 89% and a specificity of 90%. The positive predictive value (PPV) was 79% and the negative predictive value (NPV) 96%.

Additionally, the test could separate early-stage (I and II) cancer from late stage (III and IV) with similar sensitivity and specificity, with a PPV of 94% and a NPV of 89%. It could also be used to distinguish ulceration or non-ulceration among benign gastric conditions, as well as endoscopic abnormalities in patients without ulceration. This could lead to an additional use in the diagnosis of gastritis, say the authors.

The authors explain that it is often the countries with the highest prevalence of gastric cancer that have the least accessibility to endoscopy. While conversely, countries with low prevalence often overuse the invasive technique to little clinical gain. There is therefore an urgent global need for alternatives, they say.

"Breath testing is fast, simple and non invasive," write Haick with co-authors Hu Liu (Anhui Medical University, Hefei, China) and colleagues in the British Journal of Cancer.

"Hence, the test would be highly acceptable to patients and would therefore be highly suited for identifying at-risk individuals that should undergo further endoscopic investigations, while avoiding unnecessary invasive procedures."

They add that they have begun a large clinical trial of the technique to validate their findings.

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