Kelly Butler, Dr. Reham Abdel-Wahab
Cholangiocarcinoma (CCA) is often detected at an advanced stage that is difficult to treat. Early detection is an important area of research, and scientists are working to develop new tools to detect CCA in its early, more treatable stages.
A recent paper laid the necessary groundwork for diagnostic breath tests, which require distinct features in the breath of CCA patients vs. healthy individuals. The study thus compared exhaled breath samples from 30 recently diagnosed CCA patients with the same number of samples from control participants. The control group included individuals with an increased risk of CCA due to pre-existing conditions such as benign biliary stricture and non-alcoholic fatty liver disease.
The authors identified six compounds that were significantly different in the breath samples of the two groups. Four of these compounds (acetone, isopropyl alcohol, 1,4-pentadiene, and N, N-dimethylacetamide) were found at higher levels in samples from CCA patients. The remaining two (allyl methyl sulfide and dimethyl sulfide) were found at lower levels. Within the CCA group, 1,4-pentadiene was more abundant in breath samples from patients with extrahepatic vs. intrahepatic tumors.
These early-stage results are promising and suggest that breath compounds could serve as biomarkers for early detection of CCA—potentially even distinguishing between intrahepatic and extrahepatic subtypes. However, further research is needed using larger sample sizes, additional CCA subtypes, and a variety of disease stages. Validating the breath test in patients with early-stage cancer will be essential, as the CCA patients included in this study were already diagnosed and likely had advanced diseases.
If breath tests can detect early-stage CCA, they could be reasonably used as practical and non-invasive screening tools in various clinical settings. An effective screening method for CCA is urgently needed and could significantly improve patient outcomes through early detection. The Cholangiocarcinoma Foundation is thus focusing significant efforts on developing early detection tools, which could help improve outcomes for individuals with CCA.
Reference: Kabir KMM, Donald WA. Cancer breath testing: a patent review. Expert Opin Ther Pat. 2018
Mar;28(3):227-239. doi: 10.1080/13543776.2018.1423680. Epub 2018 Jan 6. PMID: 29297703.
Kelly Butler is an NIH Postbac Research Fellow and the Founding Director of SAFE
Reham Abdel-Wahab is the Cholangiocarcinoma Foundation's Director of Research and Chief Scientific Officer.