(dailyRx News) While the prevalence of a number of cancers is declining, some types are on the rise. The incidence of one of the more difficult forms of liver cancer to treat has tripled over the past 30 years. And researchers are beginning to know why.
Hepatitis C infection wreaks havoc on the liver, leaving tissue scarred and permanently damaged. Researchers now believe it's the rise in cases of hepatitis C that's behind the greatest increases in hepatocellular carcinoma (HCC) - liver cancer. Obesity also plays a role in this trend.
A study from the Mayo Clinic led by Ray Kim, M.D., a specialist in Gastroenterology and Hepatology, reviewed several decades of data from the Rochester Epidemiology Project. This review uncovered a couple of interesting facts:
- The overall incidence of HCC is higher than what the National Cancer Institute (NCI) estimates - 6.9 cases are found in 100,000 individuals vs. NCI's estimate of 5.1 per 100,000.
- Two decades ago, liver cancer typically resulted from tissue scarring caused by alcohol consumption or cirrhosis.
- HCC is now developing after an individual is infected with the hepatitis C virus.
“The liver scarring from hepatitis C can take 20 to 30 years to develop into cancer,” Dr. Kim says. “We’re now seeing cancer patients in their 50s and 60s who contracted hepatitis C 30 years ago and didn’t even know they were infected,” he said.
Along with liver diseases, 11 percent of HCC cases were associated with obesity, especially fatty liver disease. Dr. Kim believes that due to the nation's burgeoning obesity crisis, rates of liver cancer "may dramatically increase in the foreseeable future.”
“It’s a small percentage of cases overall,” Dr. Kim says. “But with the nationwide obesity epidemic, we believe the rates of liver cancer may dramatically increase in the foreseeable future.”
Another study led by Mayo Clinic researcher Abdirashid Shire, Ph.D, examined Somali immigrants. Hepatitis B, also a risk factor for HCC, is common in that country. Researchers were surprised to learn that even in this population, though, hepatitis C was the primary cause of liver cancer.
Both studies suggest individuals at greatest risk for liver cancer - people who have had hepatitis C and those who were born in countries where hepatitis is more frequent - should be screened for liver cancer, which is most treatable when it's detected early.
These two studies were funded by the National Institutes of Health and the Mayo Clinic Center for Translational Science Activities.
Findings from this research were published in the January issue of Mayo Clinic Proceedings.