Predictors of hepatocellular carcinoma recurrence post thermal ablation

Percutaneous thermal ablation (PTA) is widely used as a curative option in subjects with early stage (BCLC-A) hepatocellularcarcinoma (HCC). Despite successful ablation with completeradiological response, the risk of HCC recurrence remains high. Our primary aim therefore was to evaluate factors predicting the recurrence of HCC post PTA.

METHODS: Multi-centre retrospective study of patients treated with PTA (Radiofrequency Ablation [RFA] and Microwave Ablation[MWA]) between Jan 2006 – Dec 2012. Subjects includedwere consecutive patients who had PTA with curative intent. Subjects who had other loco-regional therapies prior to PTA or with evidence of macrovascular invasion were excluded. Primary end point was the identification of factors predicting over-all intrahepatic recurrence (IHR) using uni and multivariate analysis. IHR included both recurrence due to local tumour progression [LTP] and intrahepatic distant recurrence [IDR]. Secondary endpoints were rate of IHR (both LTP and IDR),recurrence free survival and the adverse event rate (
RESULTS: Ninety-three subjects [mean age (±SD): 62.7 (±10.1) years, 77.4%males] were included in the study. 91.2% had cirrhosis and HCV (29%), HBV (18.3%) accounted for majority of the liver disease. 11.8% had more than one nodule and the overall mean (±SD) tumour diameter was 26.1 (13.3) mm. 73.1% had RFA and the mean (±SD) follow-up duration was 421.3(±396.9) days. Overall IHR rate was 55.9% during the follow-up period with LTP in 33.3%, IDR in 29% and 6.5% had both. Overall median (±SE) recurrence free survival was 422 (±48) days. Poorly differentiated HCC was the only independent predictor of overall IHR [HR (95% CI): 6.1 (1.9-19.2), p=0.002], LTP [9.8 (2.3-41.3, p=0.002] and IDR [5.3 (1.2-22.9),p=0.03]. There was a trend towards early IHR in patients having MWA compared to RFA [median (±SE) days: 399 (±32) v554 (±111) days, p=0.06). This was more evident in single tumours less than 30 mm where the recurrence was significantly earlier in those having MWA [median (±SE) days: 399 (±37) v568 (±120) days, p=0.02]. Overall, 11.8% had an adverse event and this was higher in the MWA group compared to RFA but, not significant (25% v 9.7%, p=0.14). There were no procedure related deaths in this cohort.

CONCLUSION: Poorly differentiated HCC is an important, independent predictor of overall IHR, LTP and IDR post PTA. Trends towards earlier recurrence in patients having MWA, together with a higher adverse event rates in the MWA group raise concerns about the efficacy and safety of this technique relative to RFA in real world settings and require further study.