According to the Centers for Disease Control and Prevention (CDC), the incidence of hepatocellular carcinoma (HCC), the main type of liver cancer, is on the rise. Between 2003 and 2012, the number of new cases of HCC increased 38 percent.
“HCC is among the fastest rising cancers, if not the fastest,” says Alexandra Gangi, M.D., director of the gastrointestinal tumor program at Cedars-Sinai, in a telephone interview with HealthCentral. Moreover, she says, it’s rising faster in the U.S. than the rest of the world. In 2018, more than 41,000 people will be diagnosed with liver cancer.
Not only is the incidence of liver cancer rising, but the mortality rate is also rising at a time when the death rate of many other cancers is going down, says Theodore Welling, M.D., director of the liver tumor program at NYU Langone’s Perlmutter Cancer Center, in a telephone interview with HealthCentral. This is due to a rising epidemic in the causes of liver cancer.
What causes liver cancer?
“The greatest risk factor for liver cancer is liver disease,” Dr. Welling says. In fact, “about 90 percent of patients worldwide have some underlying liver disease.” Liver disease is any kind of cirrhosis (scarring) or presence of viral hepatitis (inflammatory liver disease), he says. Excessive alcohol consumption can cause liver cirrhosis, but so can other, non-alcohol related factors.
Metabolic disorders. According to CDC data, about 60 percent of liver cancers in the U.S. are due to risk factors we have some control over. Roughly, one-third of these are related to metabolic disorders, a category of diseases that include diabetes, impaired glucose tolerance, and obesity.
“Metabolic syndrome leads to fatty liver,” says Dr. Welling. Patients with fatty liver can develop fatty liver disease with inflammation, called NASH—nonalcoholic steatohepatitis. More and more people in the U.S. are affected by NASH and we’re also noting an increase in the numbers of liver cancers with NASH as the underlying disease, Dr. Welling says.
According to prospective studies, every incremental increase in body mass index, a measure of body fat, increases a person’s risk for developing liver cancer by about 5 percent. “We’re seeing an increase in all solid tumors with increasing rates of obesity,” says Dr. Gangi. “One of these is HCC.”
Hepatitis. Having hepatitis B and/or hepatitis C are also significant risk factors for liver cancer. Worldwide, hepatitis B causes more than half of all liver cancers, and hepatitis C causes about 20 percent of cases.
As Dr. Welling points out, we vaccinate children against hepatitis B in the U.S., so it’s not a leading cause of liver cancer, except in cities which have a high concentration of people migrating from countries where hepatitis B is common.
However, Dr. Gangi adds, nationally, hepatitis C is linked to developing HCC. She points out that hepatitis C-related increases in liver cancer are not due to a growing incidence of hepatitis C, but rather because many baby boomers (those born between 1946 and 1964) have undiagnosed and untreated hepatitis C infections. These infections have remained dormant for decades and are now being diagnosed because people have finally developed complications, such as liver tumors. Experts estimate about 3.5 million baby boomers have hepatitis C infections, most often from injection drug use, sex with an infected partner, or blood transfusions before blood banks began testing donated blood for hepatitis C in 1992.
Smoking. Finally, smoking is a significant risk factor for liver and many other types of cancer. Dr. Gangi says people who smoke are twice as likely to develop liver cancer. Fortunately, rates of smoking are going down in the U.S.
Preventing Liver Cancer
Preventing liver disease will significantly lower your risk for developing liver cancer.
“The important takeaway is that dietary modifications in the U.S. would be one of the things that would most contribute [to lowering risk for liver cancer],” says Dr. Gangi. “We have more people who are obese, who are not managing their weight appropriately and ultimately developing diabetes, obesity. These things are on the rise and we see a clear linear progression between that and HCC. All the things that are generally good for your health are also good for decreasing rates of liver cancer.”
Dr. Welling adds that regular screening in select groups is also important. “We have data showing if we have surveillance in high-risk groups [those with cirrhosis or known hepatitis], we can identify the disease at an earlier stage when we have more treatment options available,” he says.
The good news is that if you don’t have a history of liver disease, your risk of developing HCC is pretty low, less than 5 percent, says Dr. Welling.