Current Perspectives on Opisthorchiasis Control and Cholangiocarcinoma Detection in Southeast Asia

Abstract

Similar to bile duct cancer or cholangiocarcinoma (CCA) in the western world, opisthorchiasis-associated CCA in Southeast Asia is an aggressive cancer with high mortality rates. It is known to cause a significant health burden in the opisthorchiasis region in Thailand and possibly throughout mainland Southeast. To reduce this health burden, a comprehensive prevention and control program for opisthorchiasis, as well as CCA, is required. In this review, our aim is to provide a brief update of the current situation regarding the natural history of opisthorchiasis and health burden of CCA in Southeast Asia. A comprehensive approach to tackling these issues being implemented in Thailand under the "Cholangiocarcinoma Screening and Care Program" is described. This comprehensive program consists of a three stage prevention and patient care program. The primary prevention component involves opisthorchiasis screening using a new and sensitive urine assay. The secondary prevention component involves screening for CCA and periductal fibrosis, with suspected CCA patients following the protocol for confirmation and appropriate treatment. Due to the eco-epidemiology of opisthorchiasis-induced CCA, the anticipated impacts and outcomes of the program include short-, medium-, and the long-term goals for the reduction of CCA incidence. To achieve long-term sustainable impacts, concerted efforts to raise social awareness and participating action by general public, non-government organizations, and government agencies are necessary. The strategic plans developed for this program can be expanded for use in other endemic areas as well as being a model for use in other chronic diseases.

Keywords: Opisthorchis viverrini; cholangiocarcinoma; primary prevention; screening; secondary prevention; tertiary care program.

Figure 1

Distribution of Opisthorchis viverrini (OV) in Southeast Asia.

Figure 2

Opisthorchiasis-associated cholangiocarcinoma. (A) Cholangiocarcinoma specimen showing adult worms in the bile duct (blue arrows). (B) Adult Opisthorchis viverrini recovered from the liver.

Figure 3

Ultrasound image and compute tomography in cholangiocarcinoma (CCA). (A) Ultrasound image shows a mild degree of dilatation of the intrahepatic bile duct left lobe of the liver (black arrows). (B) Portal phase computed tomography shows infiltrative tumor along left hepatic duct (white arrow) with dilatation of intrahepatic duct in left lobe (black arrow). Final diagnosis is perihilar periductal CCA stage II (AJCC 7th edition).