Breath Test May Detect Esophagogastric Cancer

A breath analysis test to diagnose esophagogastric cancer demonstrated a sensitivity of 80 percent and specificity of 81 percent of a single breath test, reported the Imperial College London.

This compared with the diagnostic accuracy generated by an endoscopy referral, which had a sensitivity of 59 percent, and specificity of 81 percent. 

Unlike other diagnostic methods, this test is non-invasive.

The test looks for chemical compounds in exhaled breath that are unique to patients with oesophageal and gastric cancer.  

These cancers produce a distinctive smell of volatile organic compounds (VOC), chemicals that contain carbon and are found in all living things, which can help doctors detect early signs of the disease.  

These researchers were able to identify and quantify the number of VOCs in breath samples by using a mass spectrometer, an analytical instrument used to identify what chemicals are present in a sample.

This multi-center, clinical trial included 335 patients, which 172 patients were previously diagnosed with esophagogastric cancer. 

“There is a real need for early detection of cancer when symptoms are non-specific and shared by benign diseases. Our breath test could be used as a first-line test before invasive investigations,” said Professor George Hanna, lead author of the study. 

“Early detection of cancer gives patients more treatment options and save more lives.”

The test was used to establish the diagnostic accuracy of a previously identified set of volatile organic compounds in the breath that were abnormally regulated with the presence of esophagogastric cancer.

The researchers said this test can be used to help clinicians decide whether patients need further investigations.

They believe that in the future clinicians would order a breath test in the same way as routine blood tests.

Gastric and oesophageal cancers are mostly diagnosed at a late stage when curative treatment might not be possible. As a result, the long-term survival rate is about 15 percent in the UK.

Doctors diagnose oesophageal and gastric cancers by carrying out an endoscopy. 

This is a procedure where the inside of the body is examined using a probe with a light source and video camera at the end via the mouth and down the gullet.  

However, the procedure is invasive and only two percent of patients who are referred for an endoscopy by GPs are diagnosed with oesophageal or gastric cancer.  

There are more than 15,000 new cases of gastric and oesophageal cancers in the UK and those cancers account for 15 percent of cancer-related deaths globally.

In addition, an endoscopy procedure costs the NHS around £400-£600. 

The team are undertaking further investigations to improve the test and will conduct a larger clinical trial to validate the results in GP surgeries where the test is intended to be used and to see if the test can diagnose other cancers in the body such as the pancreas.

This research was funded by the NIHR Imperial College Biomedical Research Centre (BRC), NIHR-doctorate fellowship and Rosetress and Stoneygate Trusts. No conflicts of interest were disclosed.