The term "cholangiocarcinoma" was originally used only for intrahepatic bile duct (adeno)carcinomas, but is now regarded as inclusive of intrahepatic, perihilar, and distal extrahepatic tumors of the bile ducts. A rise in incidence of intrahepatic cholangiocarcinoma has been recently reported in Western countries but comparatively little is known about recent cholangiocarcinoma incidence trends in East and South-Eastern Asia.We compared age-adjusted incidence rates of both intrahepatic and extrahepatic cholangiocarcinomas, as well as coding practices, using data from 18 cancer registries in Asia and 4 selected registries in Western countries. Intrahepatic cholangiocarcinoma incidence rates were calculated after reallocation of cases with unknown or unspecified histology among liver cancer cases.Age-adjusted incidence rates of intrahepatic cholangiocarcinoma varied by more than 60-fold by region. The highest rates were found in Khon Kaen, Thailand, where 90% of liver tumors were cholangiocarcinomas. The next highest rates were found in the People's Republic of China, followed by the Republic of Korea. The highest age-adjusted incidence rate for extrahepatic cholangiocarcinoma was found in Korea. Coding practices for perihilar (Klatskin tumor) or unspecified sites of cholangiocarcinoma differed from one cancer registry to the other. The proportion of Klatskin tumors among cholangiocarcinomas was less than the one reported in clinical settings.Developing a consistent and uniform topographical classification for acceptable coding practice to all health professionals is necessary. In addition, epidemiological research on risk factors according to anatomical location (intrahepatic versus extrahepatic) and the macroscopic appearance and/or new histological classification of cholangiocarcinoma is also needed.
Cancer is a major cause of death in children worldwide, and the recorded incidence tends to increase with time. Internationally comparable data on childhood cancer incidence in the past two decades are scarce. This study aimed to provide internationally comparable local data on the incidence of childhood cancer to promote research of causes and implementation of childhood cancer control.
Cholangiocarcinoma is relatively rare, but high incidence rates have been reported in Eastern Asia, especially in Thailand. The etiology of this cancer of the bile ducts appears to be mostly due to specific infectious agents. In 2009, infections with the liver flukes, Clonorchis sinensis or Opistorchis viverrini, were both classified as carcinogenic to humans by the International Agency for Research on Cancer for cholangiocarcinoma. In addition, a possible association between chronic infection with hepatitis B and C viruses and cholangiocarcinoma was also noted. The meta-analysis of published literature revealed the summary relative risks of infection with liver fluke (both Opistorchis viverrini and Clonorchis sinensis), hepatitis B virus, and hepatitis C virus to be 4.8 (95% confidence interval [95% CI]: 2.8-8.4), 2.6 (95% CI: 1.5-4.6), and 1.8 (95% CI: 1.4-2.4), respectively - liver fluke infection being the strongest risk factor for cholangiocarcinoma. Countries where human liver fluke infection is endemic include China, Korea, Vietnam, Laos, and Cambodia. The number of infected persons with Clonorchis sinensis in China has been estimated at 12.5 million with considerable variations among different regions. A significant regional variation in Opistorchis viverrini prevalence was also noted in Thailand (average 9.6% or 6 million people). The implementation of a more intensive preventive and therapeutic program for liver fluke infection may reduce incidence rates of cholangiocarcinoma in endemic areas. Recently, advances have been made in the diagnosis and management of cholangiocarcinoma. Although progress on cholangiocarcinoma prevention and treatment has been steady, more studies related to classification and risk factors will be helpful to develop an advanced strategy to cure and prevent cholangiocarcinoma.
Head and neck cancers (ICD-9 categories 140-149 and 161) are common in several regions of the world where tobacco use and alcohol consumption is high. The age standardized incidence rate of head and neck cancer (around 1990) in males exceeds 30/100, 000 in regions of France, Hong Kong, the Indian sub-continent, Central and Eastern Europe, Spain, Italy, Brazil, and among US blacks. High rates (> 10/100,000) in females are found in the Indian sub-continent, Hong Kong and Philippines. The highest incidence rate reported in males is 63.58 (France, Bas-Rhin) and in females 15.97 (India, Madras). The variation in incidence of cancers by subsite of head and neck is mostly related to the relative distribution of major risk factors such as tobacco or betel quid chewing, cigarette or bidi smoking, and alcohol consumption. Some degree of misclassification by subsites is a clear possibility in view of the close proximity of the anatomical subsites. While mouth and tongue cancers are more common in the Indian sub-continent, nasopharyngeal cancer is more common in Hong Kong; pharyngeal and/or laryngeal cancers are more common in other populations. While the overall incidence rates show a declining trend in both sexes in India, Hong Kong, Brazil and US whites, an increasing trend is observed in most other populations, particularly in Central and Eastern Europe, Scandinavia, Canada, Japan and Australia. The overall trends are a reflection of underlying trends in cancers of major subsites which seem to be related to the changing prevalence of risk factors. The five year relative survival varies from 20-90% depending upon the subsite of origin and the clinical extent of disease. While primary prevention is the potential strategy for long term disease control, early detection and treatment may have limited potential to improve mortality in the short term.