In the early 1990s, the researchers conducted 2 trials of interferon therapy in patients with chronic hepatitis C and liver scarring. Patients in the trials received interferon injections 3 times a week for 26 to 88 weeks. For several years, the researchers followed these patients, as well as patients who declined antiviral therapy (median follow-up, 6.8 years). Every few months, the researchers tested the patients' blood for HCV and signs of liver inflammation, and they did liver ultrasonography to check for tumors. Additional tests, such as computed tomography and liver biopsies, were done to see whether any tumors were cancer. The researchers then compared outcomes among people who had and had not received antiviral treatment.