Effect of CyberKnife stereotactic body radiation therapy for hepatocellular carcinoma on hepatic toxicity

Abstract

ObjectiveTo evaluate the safety of CyberKnife stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) patients and identify the treatment-related risk factors of hepatic toxicity.Materials and methodsOne hundred and four HCC patients treated with CyberKnife SBRT were included in this study between August 2009 and December 2012. The average dose of prescribed radiation was 42.81±4.78 Gy (28–55 Gy) with the average fraction size of 8–16 Gy to the planning target volume. The average fractions were 3.31±0.81 (2–6 fractions). Response rates were determined, and the Child–Pugh (CP) score and class following CyberKnife SBRT were obtained to evaluate hepatic toxicity.ResultsSeventeen patients experienced progression in CP class and 24 patients experienced CTCAE V. 4.0 grade 2–3 hepatic toxicity during the five-month follow-up period, while no patient experienced grade 4 liver toxicity. Multivariate analysis indicated that only V25 was an independent factor in grade 2–3 hepatic toxicity (P=0.029, <0.05). Radiation-induced hepatic toxicity (RIHT), defined as an increase of at least two points within three months following CyberKnife SBRT, occurred in 13 of the 104 patients (13/104, 12.5%), and only the normal liver tissue was found to be associated with RIHT (P=0.008, <0.05).ConclusionCyberKnife SBRT is a feasible and safe treatment for HCC with regard to hepatic toxicity, while V25 and normal liver volume may be an independent factor of grade 2–3 hepatic toxicity and RIHT, respectively.

How small is TOO small? New liver constraint is needed— Proton therapy of hepatocellular carcinoma patients with small normal liver

“…The authors suggested that the volume of the liver receiving <18 Gy of radiation should be at least 800 cm 3 to minimize the risk of hepatic function deterioration [ 14 ]. Studies that investigated post-SBRT hepatic toxicities have suggested that NLV receiving >20 Gy or >25 Gy should be <48.5% or <31.5%, respectively [ 27 , 28 ]. In PBT, the characteristic Bragg peak results in energy release in a targeted area and then decreases drastically.…”

“…Introducing constraints by setting a limiting dose and absolute volume appears to be rational from the viewpoint of Radiation Oncology, because dose–volume histograms and common constraints are presented using these two parameters. However, none of the aforementioned studies have considered individual variations in body indexes and the necessary functional liver volume required [ 14 , 15 , 25 – 28 ]. In consideration of our patient group having relatively small NLV of <800 cm 3 , the feasibility of applying the aforementioned constraints to different patients becomes questionable.…”

“…By applying this concept to our patients, an assumption was made that the normal liver cells receiving <30 GyE are still functional [ 34 ]. In addition, constraints used in RT rarely consider individual liver volume variations and proper residual liver volume [ 14 , 15 , 25 – 28 ]. Because actual liver volumes are largely affected by tumor volume in patients with HCC, standard liver volume should be estimated using a formula.…”

CT‐guided liver beacon transponder implantation

“…However, due to the size, location, number of tumor lesions, individualized differences in patients, and early symptoms are more insidious, most patients have lost the opportunity for surgical resection at the initial diagnosis. [6][7][8] Although liver transplantation is currently considered to be the best treatment option for primary liver cancer, less than one-third of patients have liver transplantation conditions. 9,10 Radiofrequency ablation should not be used in patients with lesions adjacent to the bile duct, large blood vessels, or under the liver capsule.…”

Strategic application of radiotherapy for hepatocellular carcinoma

“…Clinical feasibility of CyberKnife system has been demonstrated in several studies, especially SBRT papers. CyberKnife SBRT has been proven to be a safe and effective noninvasive treatment for HCC [ 3 - 7 ]. CyberKnife system consists of a pair of fluoroscopes in the ceiling coupled to a small X-band linear accelerator mounted on robotic arm, which can move according to the movement of inserted fiducial markers.…”