Radiofrequency ablation versus stereotactic body radiotherapy for small hepatocellular carcinoma: a Markov model-based analysis

Abstract

The aim of this study is to compare radiofrequency ablation (RFA) with stereotactic body radiotherapy (SBRT) for hepatocellular carcinomas (HCC) smaller than 3 cm. A Markov cohort model was developed to simulate a cohort of patients aged 60-65 years with small HCCs who had undergone either RFA or SBRT and were followed up over their remaining life expectancy. The inclusion criteria were: (1) HCC ≤3 cm in diameter with ≤ 3 nodules; (2) absence of extrahepatic metastasis or portal/hepatic vein invasion; (3) Child-Pugh Class A or B. Twenty thousand virtual patients were randomly assigned to undergo RFA or SBRT. Predicted life expectancy was 6.452 and 6.371 years in the RFA and SBRT groups, respectively. The probability distributions of the expected overall survival were nearly identical. The 95% confidence intervals were 6.25-6.66 and 6.17-6.58 years for RFA and SBRT, respectively. The difference between RFA and SBRT was insignificant (P = 0.2884). Two-way sensitivity analysis demonstrated that if the tumor is 2-3 cm, SBRT is the preferred treatment option. Our Markov model has shown that expected overall survival of SBRT is nearly identical to RFA in HCCs smaller than 3 cm, but SBRT may have an advantage for tumors 2 cm and larger. A randomized trial is required to confirm these findings.

Keywords: Hepatocellular carcinoma; Markov; radiofrequency ablation; stereotactic.

Figure 1

Scenario for the Markov state transition model of HCC carcinomas less than 3 cm. Each circle represents a state of health. From the initial state, patients are randomized to undergo RFA or SBRT. Straight arrows represent the changes that may occur during each cycle or a very short time interval. In contrast, circular arrows mean that the patients may remain in the same Markov state for more than one cycle. HCC, hepatocellular carcinoma; RFA, radiofrequency ablation; SBRT, stereotactic body radiotherapy; NED, no evidence of disease; CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease.

Figure 2

Expected overall survival curves of patients with small HCCs treated with RFA or SBRT. HCC, hepatocellular carcinoma; RFA, radiofrequency ablation; SBRT, stereotactic body radiotherapy.

Figure 3

Validation of Markov model. Predicted survival curve after RFA and 95% confidence intervals (CI) from our Markov model is shown. The dots represent the survival outcomes of real studies that were marked on the survival curves. Almost all dots are positioned inside the 95% CI of the survival curve from the Markov model. CI, confidence interval; HCC, hepatocellular carcinoma; RFA, radiofrequency ablation.

Figure 4

Two‐way sensitivity analysis: 1‐year local recurrence rate after RFA or SBRT. The overall survival of patients with a 1‐year LR of 1% after SBRT was very similar to the survival of those with 1 year LR of 2% after RFA when other variable values remained constant at preset values. If the tumor size was confined from 2 cm to 3 cm, 1 year LR was 0.2109 and 0.0541 for RFA and SBRT, respectively, and SBRT was the preferred treatment option (white dot in the figure). LR, local recurrence rate; RFA, radiofrequency ablation; SBRT, stereotactic body radiotherapy.