Using breath analysis as a screening tool to detect gastric cancer: a systematic review

Breath analysis has emerged as an experimental method of non-invasive screening of gastric cancer and identification of individuals suitable for confirmatory, diagnostic upper gastrointestinal endoscopy. We aimed to evaluate the accuracy and applicability of breath analysis for gastric cancer detection in adults.We searched MEDLINE, EMBASE, BIOSIS, CENTRAL, and Compendex up to 27 September 2020 for original studies analysing exhaled breath to detect gastric cancer in patients. Summary sensitivity and specificity analyses were obtained using a hierarchical bivariate method. Non-quantitative results were descriptively summarized. Risk of bias was assessed using the QUADAS-2 tool. This study protocol was pre-registered in PROSPERO (CRD42020139422).Twenty-four studies were included. Within these, breath analysis technologies most commonly used were mass spectrometry (MS)-based methods; other methods included volatile organic compound sensors and silicon nanowire field effect transistors. Fourteen studies (totaln= 3028) involving all technologies reported quantitative results, with sensitivities ranging from 67%-100% and specificities from 71%-98%. The summary sensitivity across six studies utilizing MS-based breath analysis methods was 82.4% (95% CI: 78%-86%); summary specificity was 91.3% (95% CI: 83%-96%). Based on these values, we estimated that screening with MS-based breath tests could lower the number needed to screen (NNS) by more than eight-fold in the 15 countries with the highest prevalence of gastric cancer.Breath analysis is a promising method for gastric cancer detection with good diagnostic performance and potential to decrease the NNS for endoscopy-based gastric cancer detection. However, due to the heterogeneity of breath analysis technologies, rigorous studies with standardized, reproducible methods are needed to evaluate the clinical applicability of these technologies.