A new research study investigating scientific publications from 1995 to 2019 found a rapid increase in those related to cholangiocarcinoma (CCA). The number of articles related to CCA grew from 108 in 1995 to 776 by 2019, according to Frontiers in Oncology.

In this study, clinical terms identified from the analysis of Medical Subject Headings (MeSH) terms were divided into 3 categories: diagnosis-related, treatment-related, and prognosis-related. Within the diagnosis-related category, the most common terms found were neoplasm staging, X-ray computed tomography, and endoscopic retrograde cholangiopancreatography.

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A total of 8276 studies were found over the 25-year time period searched using the MeSH term “cholangiocarcinoma” on PubMed. The abstracts of these articles were then analyzed using the Latent Dirichlet Allocation (LDA), a machine learning method used for natural language processing, to identify glossary terms for each article. Connections between the main glossary terms were then performed using the Louvain algorithm for cluster analysis.

In cluster analysis, the LDA divided terms into 3 main clusters including treatment management, diagnosis research, and basic research. Survival analysis, chemotherapy, and hepatectomy were the top 3 terms clustered within treatment management while differential diagnosis, positron emission tomography, and contrast-enhanced computed tomography were the top issues in diagnosis research. The basic research cluster covered the widest range of topics, including gene expression profile and microRNA expression. 

Hepatectomy, stents, and liver transplantation were the top terms related to treatment. Palliative care was also commonly found in articles, indicating the poor prognosis of CCA for many patients.

For prognosis terms, survival rate and risk factors were the most common terms. The authors indicated that disease-free survival has gradually increased in usage due to its more comprehensive indication of patient prognosis than survival rate.

However, the proportions of publication types did not show many changes in recent years except for a steady increase in the proportion of meta-analyses and a decrease in the already low proportion of clinical trials (7.24% at the highest to 1.42% in 2019).

“Notably, the basic research cluster showed a poor connection with other clusters, while the strongest connections appeared between survival analysis and expression profiles of microRNA and gene, indicating that a large amount of basic researches failed to translate to clinical therapies,” the authors said.


Zhang Z, Wang Z, Huang Y. A bibliometric analysis of 8,276 publications during the past 25 years on cholangiocarcinoma by machine learning. Front Oncol. 2021;11:687904. doi:10.3389/fonc.2021.687904