Liver scarring from hepatitis C infection is driving a rise in liver cancer incidence, according to a new study from the Mayo Clinic.

Liver cancer has tripled in the U.S. over the last three decades, and what was once blamed primarily on cirrhosis from alcohol consumption appears to have additional risk factors, according to the research published in the January issue of Mayo Clinic Proceedings.

"The liver scarring from hepatitis C can take 20 to 30 years to develop into cancer," said W. Ray Kim, M.D., a specialist in Gastroenterology and Hepatology and principal investigator of one study. "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."

The research group looked at records in the Rochester Epidemiology Project, a database that accounts for Olmsted County, Minnesota’s entire inpatient and outpatient care, and found a higher overall incidence liver cancer, 6.9 per 100,000, than that estimated by the National Cancer Institute, 5.1 per 100,000.

The study was funded by the National Institutes of Health and the Mayo Clinic Center for Translational Science Activities.