Features of extrahepatic metastasis after radiofrequency ablation for hepatocellular carcinoma.

BACKGROUND

Extrahepatic metastasis (EHM) of hepatocellular carcinoma (HCC) is associated with poor outcomes. However, the clinical features and risk factors of EHM of HCC after radiofrequency ablation (RFA) remain unclear.

AIM

To elucidate the characteristics and risk factors of EHM after RFA for HCC.

METHODS

From January 2008 to December 2017, we retrospectively enrolled 661 patients who underwent RFA as first-line treatment for HCC at 2 tertiary hospitals. The inclusion criteria were age ≥ 18 years, a diagnosis of HCC, and treatment-naivety. Abdominal computed tomography (CT) or magnetic resonance imaging (MRI) and alpha-fetoprotein measurements were routinely performed at 1 mo after RFA and followed-up at intervals of 3-6 mo. Univariate analyses were performed using the chi-squared test or Student's -test, and univariate and multivariate analyses were performed logistic regression, as appropriate.

RESULTS

EHM was diagnosed in 44 patients (6.7%) during a median follow-up period of 1204 days. The 10-year cumulative rate of HCC recurrence and EHM was 92.7% and 33.7%, respectively. Initial recurrence was most often intrahepatic, and the rate of extrahepatic recurrence at initial recurrence was only 1.2%. The median time to the diagnosis of EHM was 2.68 years, and 68.2% of patients developed EHM within 2 years of the first recurrence, regardless of recurrence-free survival and 75.0% of patients developed EHM within 5 years after first recurrence. EHM was mostly diagnosed abdominal CT/MRI in 33 (75.0%) and 38 of 44 patients (86.4%) with EHM had either positive abdominal CT scan results or serum AFP level elevation. In multivariate analysis, recurrence-free survival < 2 years, ablation zone/tumor size < 2, and alpha-fetoprotein level > 400 IU/mL were associated with a high EHM risk.

CONCLUSION

EHM occurs following multiple intrahepatic recurrences after RFA and combined contrast-enhanced abdominal CT and serum AFP were useful for surveillance. Patients especially with high-risk factors require close follow-up for EHM.