Hanna GB, et al. - In order to assess the diagnostic accuracy of volatile organic compound (VOC) breath tests for cancer detection, researchers carried out a meta-analysis on studies that reported issues influencing the concentration of VOCs within exhaled breath in humans. Using the Embase and MEDLINE databases (January 1, 2000 to May 28, 2017) through the OVID platform, they identified 63 relevant publications and 3,554 patients. Researchers concluded that among the intended population in multicenter clinical trials, standardization of breath collection methods and masked validation of breath test accuracy for cancer diagnosis was needed. A framework to guide the conduct of future breath tests in cancer studies was proposed. According to this systematic review, factors that might influence variability in test results included breath collection method, patient physiologic condition, test environment, and method of analysis.