Opisthorchiasis and cholangiocarcinoma in Southeast Asia: an unresolved problem

Abstract

Thomas Hughes,1,* Thomas O’Connor,1,* Anchalee Techasen,2,3 Nisana Namwat,2,3 Watcharin Loilome,2,3 Ross H Andrews,2–4 Narong Khuntikeo,3,5 Puangrat Yongvanit,3,6 Paiboon Sithithaworn,3,7 Simon D Taylor-Robinson1 1Division of Digestive Health, Department of Surgery and Cancer, Imperial College London, London, UK; 2Department of Biochemistry, Faculty of Medicine, Liver Fluke and Cholangiocarcinoma Centre, 3Cholangiocarcinoma Screening and Care Program (CASCAP), Khon Kaen University, Khon Kaen, Thailand; 4Faculty of Medicine, St Mary’s Campus, Imperial College, London, UK; 5Department of Surgery, 6Department of Biochemistry, 7Department of Parasitology, Faculty of Medicine, Liver Fluke and Cholangiocarcinoma Centre, Khon Kaen University, Khon Kaen, Thailand *These authors contributed equally to this work Abstract: The prevalence of cholangiocarcinoma (CCA) in Southeast Asia is much higher than other areas of the world. Eating raw, fermented, or undercooked cyprinid fish, infected with the liver fluke, Opisthorchis viverrini sensu lato (sl), results in chronic biliary inflammation, periductal fibrosis, and increased cancer risk. There may be associated glomerulonephritis. The process of infection is difficult to disrupt because eating practices have proven extremely difficult to change, and the life cycle of the fluke cannot be broken due to high prevalence in canine and feline reservoir hosts. Fecal analysis and enzyme-linked immunosorbent assay tests can be used to diagnose opisthorchiasis. Diagnosis of CCA is complex, partly due to the lack of definitive imaging characteristics but also due to the difficulty of obtaining samples for cytology or histology. This cancer has proven to be resistant to common chemotherapy treatments and so the two avenues of treatment available are surgical resection and liver transplantation, both requiring early detection of the tumor for the best chances of success. Late presentation of symptoms reduces the chances of successful surgical intervention. While liver fluke infections can be treated with praziquantel, individuals will often become reinfected, and multiple reinfections can be more harmful than a singular, long-term infection. A key research on the detection and characterization of novel biomarkers in all parts of the carcinogenic pathway for early diagnosis is needed. Keywords: Opisthorchis viverrini, CCA, Thailand, Laos, treatment, parasite, carcinogen, public health, helminth

Keywords

• Opisthorchis viverrini
• opisthorchiasis
• cholangiocarcinoma
• Thailand
• treatment