Background and Objectives: Chronic hepatitis C virus infection affects about 71 million people worldwide. It is one of the most common chronic liver conditions associated with an increased risk of developing liver cirrhosis and cancer. The aim of this study was to evaluate changes in liver fibrosis and the risk of developing hepatocellular carcinoma after direct-acting antiviral drug therapy, and to assess factors, linked with these outcomes. Materials and Methods: 70 chronic hepatitis C patients were evaluated for factors linked to increased risk of de novo liver cancer and ≥ 20% decrease of ultrasound transient elastography values 12 weeks after the end of treatment. Results: The primary outcome was an improvement of liver stiffness at the end of treatment (p = 0.004), except for patients with diabetes mellitus type 2 (p = 0.49). Logistic regression analysis revealed factors associated with ≥ 20% decrease of liver stiffness values: lower degree of steatosis in liver tissue biopsy (p = 0.053); no history of interferon-based therapy (p = 0.045); elevated liver enzymes (p = 0.023–0.036); higher baseline liver stiffness value (p = 0.045) and absence of splenomegaly (p = 0.035). Hepatocellular carcinoma developed in 4 (5.7%) patients, all with high alpha-fetoprotein values (p = 0.0043) and hypoechoic liver mass (p = 0.0001), three of these patients had diabetes mellitus type 2. Conclusions: Liver stiffness decrease was significant as early as 12 weeks after the end of treatment. Patients with diabetes and advanced liver disease are at higher risk of developing non-regressive fibrosis and hepatocellular carcinoma even after successful treatment.