Feasibility of volatile organic compound in breath analysis in the follow-up of colorectal cancer: A pilot study.

Background: Colorectal carcinoma (CRC) has a worldwide incidence of 1.4 million patients and a large share in cancer-related mortality. After curative treatment, the risk of recurrence is 30-65%. Early detection may result in curative treatment. However, current follow-up (FU) examinations have low sensitivity ranging from 49 to 85% and are associated with high costs. Therefore, the search for a new diagnostic tool is justified. Analysis of volatile organic compound in exhaled air through an electronic nose (eNose) is a promising new patient-friendly diagnostic tool. We studied whether the eNose under investigation, the Aeonose™, is able to detect local recurrence or metastases of CRC.

Methods: In this cross-sectional study we included 62 patients, all of whom underwent curative treatment for CRC in the past 5 years. Thirty-six of them had no metastases and 26 had extraluminal local recurrence or metastases of CRC, detected during FU. Breath testing was performed and machine learning was used to predict extraluminal recurrences or metastases, and based on the receiver operating characteristics (ROC)-curve both sensitivity and specificity were calculated.

Results: The eNose identified extra luminal local recurrences or metastases of CRC with a sensitivity and specificity of 0.88 (CI 0.69-0.97) and 0.75 (CI 0.57-0.87), respectively, with an overall accuracy of 0.81.

Discussion: This eNose may be a promising tool in detecting extraluminal local recurrences or metastases in the FU of curatively treated CRC. However, a well-designed prospective study is warranted to show its accuracy and predictive value before it can be used in clinical practice.