Breath Test Could Detect And Diagnose Stomach Cancer
The researchers hope the breath test will offer an easier screening tool than endoscopy, where a specially trained medical professional looks at the inside of the stomach via a tube inserted down the patient's gullet, and sometimes also retrieves a biopsy sample of the stomach lining.
Senior author Hossam Haick, a professor in the Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, at Technion, the Israel Institute of Technology, says in a press statement:
"The promising findings from this early study suggest that using a breath test to diagnose stomach cancers, as well as more benign complaints, could be a future alternative to endoscopies - which can be costly and time consuming, as well as unpleasant to the patient."
He cautions, however, that the findings of the pilot study are still at "an early stage", and serve more to confirm the idea that a breath test for stomach cancer is worth investigating further.
"Indeed, we're already building on the success of this study with a larger-scale clinical trial," says Haick.
Haick has been studying the effectiveness of nanoparticle sensors as a way to detect minute traces of disease biomarkers for a while. The sensors use materials that are thousands of times smaller than the thickness of human hair, and capable of detecting just a handful of molecules.
In 2011, the British Journal of Cancer reported how a nanosensor "nose" developed by Haick and his team successfully distinguished patients with head and neck or lung cancer from healthy controls by analyzing patterns of molecules in their exhaled breath.
For this latest pilot study, the researchers used nanomaterial-based sensors to analyze breath samples from 130 patients who had undergone endoscopy, some with biopsy. 37 of the patients had been diagnosed with stomach cancer, 32 had ulcers, and 61 had less severe stomach complaints.
The nanomaterial sensors showed an over 90% success rate in distinguishing the patients with stomach cancer from those with more benign complaints.
Plus, they were more than 90% accurate at distinguishing early from late stage stomach cancers.
In their background to the study, the researchers explain how there is a high demand, especially in the developing world, for "a simple and non-invasive test for selecting the individuals at increased risk that should undergo the endoscopic examination".
The procedure uses a method called "discriminant factor analysis (DFA) pattern recognition", to detect specific combinations of different exhaled chemicals and find recurring patterns in people with the same stomach complaint.
The analysis takes into account possible confounding factors such as effects from alcohol and tobacco consumption.
The researchers conclude that:
"Although this pilot study does not allow drawing far-reaching conclusions, the encouraging preliminary results presented here have initiated a large multicentre clinical trial to confirm the observed patterns for GC [gastric cancer] and benign gastric conditions."
Kate Law, director of clinical research at Cancer Research UK, says, "Any test that could help diagnose stomach cancers earlier would make a difference to patients' long-term survival."
"Only 1 in 5 people are able to have surgery as part of their treatment as most stomach cancers are diagnosed at stages that are too advanced for surgery," says Law.
Every year in the UK, around 7,000 people develop stomach cancer, and most are in the advanced stage when they are diagnosed.
One of the reasons for late diagnosis is because early stage symptoms are vague and similar to more benign conditions.
The early symptoms of stomach cancer, also called gastric cancer, include: indigestion, heartburn, stomach ache, and feeling very full after eating.
When the cancer reaches a more advanced stage, blood starts to appear in the stools, they become black, and the person also loses weight and lacks appetite.
As well as creating new options for disease diagnosis, nanotechnology is also opening new avenues in drug delivery, gene therapy, and many areas of research, development and clinical application.
Written by Catharine Paddock PhD