- BACKGROUND: Direct-acting anti-viral therapy (DAA) has transformed hepatitis C virus (HCV) care, particularly in patients with decompensated cirrhosis. However, their impact on hepatocellular carcinoma (HCC) remains unclear. AIM: To use a national registry of patients with advanced liver disease to explore the relationship between DAA therapy and HCC. METHODS: All patients with de novo HCC post DAA therapy were frequency matched with patients who did not develop HCC. Demographic, clinical and laboratory data were obtained. Cross-sectional imaging and multidisciplinary team reports were reviewed for dates of HCC diagnosis and HCC progression. Patients were categorised by treatment outcome and time of HCC development. Data were examined by multivariable analysis and Kaplan-Meier estimation. RESULTS: Eighty patients with HCC were compared with 165 patients without HCC, treated between June 2014 and September 2015. Mean follow-up from start of DAA therapy was 32.4 months. Twenty-eight patients were diagnosed with early HCC (within 6 months of therapy) and 52 presented late. Baseline nonmalignant lesions (HR: 1.99), thrombocytopaenia (HR: 1.59) and diabetes (HR: 1.68) increased likelihood of HCC. Response to therapy was reduced in patients who developed liver cancer (SVR in patients with HCC = 54/80 (68%), SVR in patients without HCC = 143/165 (87%), P < 0.001, OR: 3.13, 95% CI: 1.64-5.99). We found no difference between tumour size, progression or survival between viraemic and nonviraemic patients. CONCLUSION: There is no alteration in prognosis or cancer progression following HCC development after HCV treatment. However, baseline nonmalignant liver lesions, diabetes and thrombocytopaenia increase the risk of HCC, and HCC is associated with a decreased SVR rate.