['Critical recurrences after radiofrequency ablation for hepatocellular carcinoma (HCC), such as intrahepatic metastases or dissemination, and extrahepatic metastases or seeding, which are difficult to treat radically, almost certainly lead to primary cancer death. The present study aimed to clarify whether the arterial tumor enhancement pattern on contrast-enhanced computed tomography (CECT) is associated with critical recurrence and cancer death after RFA for small HCC.', 'Between April 2001 and September 2011, 226 patients with initial small hypervascular HCC (≤3 cm in diameter and ≤3 tumors) were treated by RFA. Arterial tumor enhancement patterns on CECT before RFA were categorized by whether non-enhanced areas were included inside the tumor stain.', 'The heterogeneous enhancement group included 44 patients, and the homogeneous enhancement group included 182 patients. The cumulative 5-year critical recurrence rates of the heterogeneous and homogeneous enhancement groups were 42 and 22% (p = 0.005), respectively. Univariate analysis for factors related to critical recurrence showed significant differences in sex, arterial enhancement pattern, and response to antiviral therapy. These factors were independent on multivariate analysis. The cumulative 5-year primary cancer death rates of the heterogeneous and homogeneous enhancement groups were 29 and 13% (p = 0.002), respectively. Univariate analysis for factors related to primary cancer death showed significant differences in arterial enhancement pattern and response to antiviral therapy. These factors were independent on multivariate analysis.'] Is the arterial tumor enhancement pattern on contrast-enhanced computed tomography associated with primary cancer death after radiofrequency ablation for small hepatocellular carcinoma?