Early diagnosis of breast cancer from exhaled breath by gas chromatography‐mass spectrometry (GC/MS) analysis: A prospective cohort study

Background It has proved that there is an association between cancer and volatile organic compounds (VOCs) of exhaled breath. This study targets on verifying the existence of specific VOCs in breathing in breast cancer patients, especially those with ductal carcinoma in situ (DCIS). Methods There were a total of 203 participants included in the final analysis, which included 71 (35.0%) patients with histologically confirmed breast cancer (including 13 with DCIS, 31 with lymph node metastasis‐negative status, and 27 with lymph node metastasis‐positive status), 78 (38.4%) healthy volunteers, and 54 (26.6%) patients with histologically confirmed gastric cancer. Gas chromatography‐mass spectrometry and solid‐phase microextraction were used to analyze the breath samples for the presence of VOCs. Results There were significant differences in the volatile organic metabolites between the DCIS, lymph node metastasis‐negative breast cancer, and lymph node metastasis‐positive breast cancer groups compared with the healthy controls as well as between the breast cancer and gastric cancer patients. An overlapping set of seven VOCs, including ( S )‐1,2‐propanediol, cyclopentanone, ethylene carbonate, 3‐methoxy‐1,2‐propanediol, 3‐methylpyridine, phenol, and tetramethylsilane, was significantly different between the breast cancer patients and healthy individuals as well as between the breast cancer and gastric cancer patients. The combination of these seven compounds was considered as a biomarker for breast cancer. The sensitivity for predicting DCIS by this set of seven compounds was determined to be 80.77%, and the specificity was determined to be 100%. Conclusions This set of seven breast cancer‐specific VOCs can be regarded as one particular expiratory marker for DCIS and will help to establish new screening methods for early breast cancer.