Cholangiocarcinoma (CCA) knows no geographic borders. Nevertheless, some geographical areas in the world are associated with increased risk for this type of cancer, according to recent research. At the 2020 virtual conference of the Cholangiocarcinoma Foundation, several experts presented global perspectives related to global trends in CCA.
Juan W. Valle, MB ChB, MSc, FRCP, Professor and Honorary Consultant in Medical Oncology, the Christie NHS Foundation Trust, Manchester, England, provided a clinician’s perspective on the epidemiology of CCA in Europe. Dr Valle presented the findings of a recent paper published in 2019.1 Bertuccio and colleagues examined the global trends in mortality rates from intrahepatic CCA, in men and women between 1995 and 2016.
Dr Valle presented an analysis of mortality rates globally for people with CCA, by age and by sex. The study showed that in the early 2000 years, the mortality rates for intrahepatic CCA were consistently below 1 patient per 100,000 population.
However, these rates increased over time. By 2014, the mortality rates for men with intrahepatic CCA increased to 1 to 2 per 100,000 men in most European countries; the rates also increased for women compared with the early 2000s, but overall, the death rates were lower for women than for men.
By contrast, the mortality rates for patients with extrahepatic CCA during the early 2000 years ranged from 0.4 to 0.9 per 100,000 population and has since decreased between the years 2010 to 2014.
Dr Valle addressed the question as to why the mortality rate for people with intrahepatic CCA has been increasing. He noted that the observed increase in mortality reflects the increase in the incidence of intrahepatic CCA over time. This increase, he noted, may be the result of improved diagnosis of CCA thanks to better imaging studies, but it is more likely that the diagnosis of intrahepatic CCAs has been confounded by a misdiagnosis.
In fact, the recent increase in incidence in intrahepatic CCA likely reflects increased understanding of CCA by physicians.
Samuel O. Antwi, PhD, MPH, Assistant Professor of Epidemiology, Mayo Clinic, Jacksonville, FL, presented an update on the epidemiologic data from the United States.
According to Dr Antwi, the incidence of intrahepatic and extrahepatic CCA in the United States is higher in men than in women (ratio, 1.2 to 1.5, respectively). Specifically, the highest incidence of the 2 subtypes of CCA is in Hispanic Americans (31% higher than other ethnic groups) as well as Asian-Americans. In addition, the overall 5-year survival rate is <10%, with poorer survival seen in African-Americans, Native Americans, and Hispanic Americans.
Dr Antwi pointed out that as in Europe, the incidence rate of intrahepatic CCA in the United States has also been increasing, and for the same reasons outlined by Dr Valle, with the rate of new cases of extrahepatic CCA remaining relatively stable.
Furthermore, in the United States, according to Dr Antwi, a diagnosis of CCA is rare before the age of 40 years. The majority of patients with CCA are diagnosed after age 60 years; overall, 27% of individuals are diagnosed with intrahepatic CCA and 19% are diagnosed with extrahepatic CCA before age 60 years in the United States.
The most common age of intrahepatic CCA diagnosis is approximately age 67, and age 72 years for extrahepatic CCA.
“It is difficult to compare epidemiologic data from the United States to other parts of the world, because the estimates were performed in different date ranges,” Dr Antwi said. “So, we are not looking at the same data, but one thing that can be claimed is that incidence rates across the globe do differ geographically, primarily due to the geographic diversity in risk factors,” he concluded.
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