Identifying the optimal criteria of radiotherapeutic parameters for patients with unresectable locally advanced hepatocellular carcinoma

The purpose of this study is to identify the optimal criteria of the radiotherapeutic parameters in patients with unresectable locally advanced hepatocellular carcinoma (HCC). 103 patients were enrolled in this study. All patients received RT delivered using the TomoTherapy Hi-Art system between March 2006 and February 2012. We evaluated the planning target volume (PTV), total dose (Gy(10)), and NTNL-V(BED20) (non-target normal liver volume receiving more than a biologically effective dose of 20 Gy(8)) as significant radiotherapeutic parameters associated with hepatic function deterioration and local progression-free survival (PFS). A PTV of 279 cm(3) or 304 cm(3), a total dose of 60 Gy(10), and a NTNL-V(BED20) of 40.8% were identified as the optimal cut-off values of radiotherapeutic parameters to prevent hepatic function deterioration and prolong local PFS. Based on these findings, patients were divided in a favorable and an unfavorable prognosis group. The differences in median local PFS, overall survival, and incidence of deteriorated hepatic function between the two groups were 11.2 months, 11.1 months, and 71.7%, respectively (p < 0.001 in each case). In conclusion, we suggest that the optimal criteria of the radiotherapeutic parameters for patients with unresectable locally advanced HCC are: PTV ≤ 279 cm(3), total dose > 60 Gy(10), and NTNL-V(BED20) ≤ 40.8%.