Cholangiocarcinoma (CCA) is an aggressive cancer arising from epithelial cells of the bile duct. Most patients with CCA have an unresectable tumor at the time of diagnosis. In Western countries, the risk of CCA increases in patients with primary sclerosing cholangitis, whereas liver fluke infection appears to be the major risk factor for CCA in Asian countries. A diagnosis of liver fluke infection often relies on stool samples, including microscopic examination, polymerase chain reaction-based assays, and fluke antigen detection. Tests of serum, saliva and urine samples are also potentially diagnostic. The presence of liver fluke along with exogenous carcinogens magnifies the risk of CCA in people living in endemic areas. The “liver fluke-cholangiocarcinoma” carcinogenesis pathways consist of mechanical damage to the bile duct epithelium, immunopathologic and cellular reactions to the liver fluke's antigens and excretory/secretory products, liver fluke-induced changes in the biliary tract microbiome and the effects of repeated treatment for liver fluke. A vaccine and novel biomarkers are needed for the primary and secondary prevention of CCA in endemic areas. Importantly, climate change exerts an effect on vector-borne parasitic diseases, and awareness of liver fluke should be enhanced in potentially migrated habitat areas.
Asian Continental Ancestry Group ; Bile Ducts ; Biliary Tract Neoplasms* ; Biliary Tract* ; Biomarkers ; Carcinogenesis ; Carcinogens ; Cholangiocarcinoma ; Cholangitis, Sclerosing ; Climate Change ; Clonorchiasis ; Diagnosis ; Ecosystem ; Epithelial Cells ; Epithelium ; Fasciola hepatica ; Humans ; Liver* ; Microbiota ; Opisthorchiasis ; Parasitic Diseases ; Risk Factors ; Saliva ; Secondary Prevention ; Trematoda

Background/Aims: Ultrasonography has a low sensitivity for detecting early-stage hepatocellular carcinoma (HCC) in cirrhotic patients. Non-contrast abbreviated magnetic resonance imaging (aMRI) demonstrated a comparable performance to that of magnetic resonance imaging without the risk of contrast media exposure and at a lower cost than that of full diagnostic MRI. We aimed to investigate the cost-effectiveness of non-contrast aMRI for HCC surveillance in cirrhotic patients, using ultrasonography with alpha-fetoprotein (AFP) as a reference. Methods: Cost-utility analysis was performed using a Markov model in Thailand and the United States. Incremental cost-effectiveness ratios were calculated using the total costs and qualityadjusted life years (QALYs) gained in each strategy. Surveillance protocols were considered cost-effective based on a willingness-to-pay value of $4,665 (160,000 Thai Baht) in Thailand and $50,000 in the United States. Results: aMRI was cost-effective in both countries with incremental cost-effectiveness ratios of $3,667/QALY in Thailand and $37,062/QALY in the United States. Patient-level microsimulations showed consistent findings that aMRI was cost-effective in both countries. By probabilistic sensitivity analysis, aMRI was found to be more cost-effective than combined ultrasonography and AFP with a probability of 0.77 in Thailand and 0.98 in the United States. By sensitivity analyses, annual HCC incidence was revealed as the most influential factor affecting cost-effectiveness.The cost-effectiveness of aMRI increased in settings with a higher HCC incidence. At a higher HCC incidence, aMRI would remain cost-effective at a higher aMRI-to-ultrasonography with AFP cost ratio. Conclusions Compared to ultrasonography with AFP, non-contrast aMRI is a cost-effective strategy for HCC surveillance and may be useful for such surveillance in cirrhotic patients, especially in those with high HCC risks.