Breath test a promising tool for early detection of gastric and oesophegeal cancers
A recent study presented at the European Cancer Congress 2017 (ECCO 2017) in Amsterdam, the Netherlands, shows promise with a breath test measuring five chemicals in the detection of possible gastric and oesophageal cancers.
The study included 335 breath samples from patients, of which 163 were diagnosed with gastric and oesophageal cancers and 172 showed gastrointestinal symptoms but were without cancer. The patients were from four centres in the UK: St. Mary’s Hospital London, Imperial College Healthcare NHS Trust, University College London Hospital and the Royal Marsden Hospital London. Researchers measured five volatile organic compounds (butyric, petanoic and hexanoic acids, butanal and decanal) in the patients’ breath samples to generate a receiver operating characteristic (ROC) curve value of 0.85±0.02, which translated to 80 percent sensitivity and 81 percent specificity. [ECCO 2017, abstract 6LBA]
“This means that the breath test is good at picking up those who have cancer [sensitive] and also good at identifying patients without cancer [specific]. Because cancer cells are different from healthy ones, they produce a different mixture of chemicals. This study suggests that we may be able to detect these differences indicating which patients are likely to have cancers of the oesophagus and stomach and which do not,” explained Dr Sheraz Markar, from the Department of Surgery and Cancer, Imperial College London, UK, one of the investigators of the study.
“At present, the only way to diagnose gastric and oesophageal cancer is with endoscopy. This method is expensive, invasive and is associated with some complications,” Markar added. “A breath test could be used as a noninvasive, first-line test to reduce the number of negative endoscopies, which will benefit healthcare systems in the long run.”
The five volatile organic compounds were measured using a method known as selected ion flow-tube mass spectrophotometry (SIFT-MS). Quality assurance assessments, done to ensure accuracy of the results obtained, were performed by calibration to water, taking samples from ambient room air and cross-platform validation using Thermal Desorption Gas Chromatography Mass Spectrometry (TD-GC-MS). [BMJ Open 2016;6:e009139]
“Four of the five volatile organic compounds were significantly dysregulated in the group of patients with gastric and oesophageal cancers compared with the control group. This association with gastric and oesophageal cancers persisted after adjustment for confounders, including patient age, medical comorbidities and medications,” Markar reported.
Future directions of the project involve evaluation of the breath test in a larger trial in patients who are undergoing endoscopy for upper gastrointestinal symptoms but are not yet diagnosed with cancer. The research team also started exploring the use of this breath test in other types of cancer, such as colorectal and pancreatic cancers.
“The technology used in this study shows great potential for early diagnosis of gastric and oesophageal cancers, which may lead to improved survival. Patients with gastric and oesophageal cancers usually present late and have high cancer-related mortality rates,” Markar concluded.
Around 951,600 new gastric cancer cases and 723,100 gastric cancer deaths were reported globally in 2012, making it the second most common cause of cancer-related mortality. In the same year, an estimated 455,800 new cases of oesophageal cancer and 400,200 oesophageal cancer deaths were reported worldwide, ranking it sixth among all cancers in terms of mortality. [CA Cancer J Clin 2015;65:87-108; J Carcinog 2014;13:14; World J Gastroenterol 2013;19:5598-5606]