A BREATH TEST TO FIND AND PREDICT STOMACH CANCER
A recent publication in the "Gut" journal describes a method that could be used to diagnose stomach cancer, and assess the risk for a specific person to have one. Approximately 24,590 people in US are annually diagnosed with this type of cancer. It usually manifests in elderly people around 69th year of life.
The disease is usually asymptomatic during its early development, making the diagnostics very difficult. In rare cases when it does cause the symptoms, those usually are loss of appetite, weight loss, stomach pains and nausea. Obviously, all of the listed symptoms can be easily ascribed to other medical conditions.
Thus, among five cases of stomach cancer only one gets a proper diagnosis before the disease spreads to the other organs. This fact means that additional tools are required to distinguish a disease in an early stage. Doing so can improve the overall treatment outcome dynamic.
The latest research of Prof. Hossam Haick and his team at IIT (Israel Institute of Technology) studied the potential of the nanoarray analysis for early warning cancer screenings. The technology is designed to measure the changes in the floating particles of gut compounds, which are exhaled by the patient.
The team pointed out, that the technology was initially designed to identify stomach cancer, and its ability to detect the early stages of the disease was still not assessed.
They hope, that the nanoarray analysis can potentialy become an 'accurate, noninvasive and low-cost' screening tool’.
The study by Prof. Haick included 484 subjects, 99 of whom had been previously diagnosed with stomach cancer, but had not received their chemotherapy or radiotherapy treatment yet.
The subjects were deprived of food for 12 hours and before sample collection and had to abstain smoking for at least 3 hours beforehand. The patients were also tested for Helicobacter pylori infection (a known cause for stomach cancer) and a thorough analysis of their drinking and smoking habits were conducted.
The first sample was analyzed using gas chromatography-mass spectrometry (GCMS), which measures the quantity of volatile organic components (VOCs) in the patient’s exhaled breath. The second sample was studied using the complex of nanoarray analysis and pattern recognition.
130 VOCs were distinguished in patient’s exhaled breath. By comparing the results of previously diagnosed patients with those, whose changes in VOC’s levels were deemed precancerous, the team came up with eight “breath-prints”.
When the nanoarray method was applied, the scientists found out, that it was able to distinguish the breath-print compositions in patients with confirmed stomach cancer, and in high and low rick groups. The results state that the method has 73% sensitivity, 98% specificity and 92% accuracy.
The researchers emphasize, that there were no changes in the results even after evaluating some distorting factors such as age, alcohol habits and use of proton pump inhibitors (gastric acid secretion reducers).
The GCMS method is unavailable for cancer screening because its complex and costly, but the nanoarray technique seems to be an easy and money saving alternative.
The scientists say that the attraction of this test lies in its noninvasiveness, ease of use (therefore high compliance would be expected), rapid predictiveness, insensitivity to confounding factors and potentially low cost.
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