Stereotactic body radiation therapy in hepatocellular carcinoma: Optimal treatment strategies based on liver segmentation and functional hepatic reserve.

AIM: To discuss current dosage for stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) patients and suggest alternative treatment strategies according to liver segmentation as defined by the Couinaud classification.
BACKGROUND: SBRT is a safe and effective alternative treatment for HCC patients who are unable to undergo liver ablation/resection. However, the SBRT fractionation schemes and treatment planning strategies are not well established.
MATERIALS AND METHODS: In this article, the latest developments and key findings from research studies exploring the efficacy of SBRT fractionation schemes for treatment of HCC are reviewed. Patients' characteristics, fractionation schemes, treatment outcomes and toxicities were compiled. Special attention was focused on SBRT fractionation approaches that take into consideration liver segmentation according to the Couinaud classification and functional hepatic reserve based on Child-Pugh (CP) liver cirrhosis classification.
RESULTS: The most common SBRT fractionation schemes for HCC were 3 × 10-20 Gy, 4-6 × 8-10 Gy, and 10 × 5-5.5 Gy. Based on previous SBRT studies, and in consideration of tumor size and CP classification, we proposed 3 × 15-25 Gy for patients with tumor size <3 cm and adequate liver reserve (CP-A score 5), 5 × 10-12 Gy for patients with tumor sizes between 3 and 5 cm or inadequate liver reserve (CP-A score 6), and 10 × 5-5.5 Gy for patients with tumor size >5 cm or CP-B score.
CONCLUSIONS: Treatment schemes in SBRT for HCC vary according to liver segmentation and functional hepatic reserve. Further prospective studies may be necessary to identify the optimal dose of SBRT for HCC.