Volatile organic compounds analysis as a potential novel screening tool for colorectal cancer: A systematic review and meta-analysis

The purpose of this meta-analysis was to assess the usefulness of volatile organic compounds (VOC) as a potential novel biomarker for colorectal cancer (CRC). We systematically searched PubMed, Embase, Web of Science, and Cochrane Library databases for observational studies (published before November 25th, 2019; no language restrictions) comparing the VOC analysis between patients with CRC and healthy controls. We evaluated the pooled sensitivity, specificity, diagnostic odds ratio, positive and negative likelihood ratio, as well as summary receiver operating characteristic curve and area under the curve. We identified a total of 10 observational studies that included 381 patients with CRC and 436 healthy controls. Bivariate analysis yielded a pooled sensitivity of 0.82 (95% confidence interval [CI] = 0.77–0.86), specificity of 0.79 (95% CI = 0.71–0.85), positive likelihood ratio of 3.8 (95% CI = 2.8–5.3), and negative likelihood ratio of 0.23 (95% CI = 0.17–0.30). The area under the curve was 0.87 (95% CI = 0.84–0.90). The pooled diagnostic odds ratio was 17 (95% CI = 10–28). Sensitivity analysis indicated that the pooled results were stabilized. The Deeks’ funnel plot asymmetry test (P = .41) suggested no potential publication bias. Our pooled data confirmed the associations between VOC analysis and CRC, highlighting the usefulness of VOC analysis as a potential novel screening tool for CRC. However, standardization of VOC collection and analysis methods for CRC screening is required in future research.