Role of exhaled hydrogen sulfide in the diagnosis of colorectal cancer.

Background: Colorectal cancer (CRC) is often accompanied by increased excretion of hydrogen sulfide (H₂S). This study aimed to explore the value of exhaled H₂S in the diagnosis of CRC.

Methods: A total of 80 people with normal colonoscopy results and 57 patients with CRC were enrolled into the present observational cohort study. Exhaled oral and nasal H₂S were detected by Nanocoulomb breath analyser. Results were compared between the two groups. Receiver operating characteristic (ROC) curves were analysed and area under the curves (AUCs) were calculated to assess the diagnostic value of exhaled H₂S. Meanwhile, the clinicopathological features, including gender, lesion location and tumour staging of patients with CRC, were also collected and analysed.

Results: The amount of exhaled H₂S from patients with CRC was significantly higher than that of those with normal colonoscopy results. The ROC curve showed an AUC value of 0.73 and 0.71 based on oral and nasal H₂S detection, respectively. The exhaled H₂S in patients with CRC was correlated with gender, lesion location and tumour progression, including depth of invasion, lymphatic metastasis and TNM (Tumor, Lymph Nodes, Metastasis) staging.

Conclusion: Exhaled H₂S analysis is a convenient and non-invasive detection method for diagnosing CRC, suggesting a potential role in population screening for CRC.