Incidence rates of the two most common types of liver cancer, HCC and ICC, have increased in the United States.
According to a recent population-based study, incidence rates of the two most common types of liver cancer, hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), have increased in the United States; the study also found that metabolic syndrome significantly increases an individual’s risk of developing these liver cancers.
Data from the National Cancer Institute showed that, in the year 2010, there were 24,120 new cases of liver and intrahepatic bile duct cancer, and there were almost 19,000 deaths which occurred in the United States as a result of the diseases.
It is known that the major risk factors for HCC are chronic infection with hepatitis B and C viruses, as well as excessive alcohol consumption.
ICC is linked to primary sclerosing cholangitis and inflammatory bowel disease, but the cause of up to half of HCC and ICC remains unknown.
"There has been an increase in the incidence rates of liver cancer—HCC and ICC—in the U.S.," reported lead author Tania Welzel, M.D., with the National Cancer Institute and Klinikum der J.W. Goethe-Universität. "While metabolic syndrome is a recognized risk factor for HCC and may also modify ICC risk, the magnitude of this effect has not been investigated on a large scale in the U.S."
For this most recent study, Welzel and fellow researchers analyzed the link between metabolic syndrome and the risk of developing primary liver cancers in the general American population.
The researchers utilized the SEER-Medicare database in order to identify individuals diagnosed with HCC or ICC between the years of 1993 and 2005.
The researchers then selected a small 5% sample group of these individuals residing in geographic regions similar to SEER registries in order to compare findings.
According to the results of this comparison, the researchers identified a total of 3,649 HCC cases, 743 ICC cases, and 195,953 people without cancer and met study inclusion criteria.
The outcome of the study showed that metabolic syndrome was exhibited in 37% of individuals who went on to develop HCC, and was exhibited in 30% of individuals who went on to develop ICC, in comparison to 17% of individuals who developed neither cancer.
Further examination revealed that metabolic syndrome was significantly connected to an increased risk of HCC (odds ratio=2.13) and ICC (odds ratio=1.56).
They also determined that individual components of metabolic syndrome such as impaired fasting glucose level, dyslipoproteinemia, obesity, and hypertension were more frequently seen among participants who developed either HCC or ICC than among participants who did not.
"Our findings show a 2-fold increased risk for HCC and a 1.56-fold increased risk for ICC in those individuals with pre-existing metabolic syndrome," reported Welzel. "The risk of developing these primary liver cancers is significant for individuals with this condition. Due to the high prevalence of metabolic syndrome, even small increases in the absolute risk for HCC and ICC may contribute to the increasing liver cancer burden."
The authors went on to suggest that metabolic syndrome could be the cause of numerous idiopathic HCC or ICC cases in the United States. As such, global efforts to control the obesity and diabetes epidemics might also help to reduce the increasing rates of liver cancer.
This study was published in the August issue of Hepatology, a journal of the American Association for the Study of Liver Diseases.