Normal liver sparing by proton beam therapy for hepatocellular carcinoma: Comparison with helical intensity modulated radiotherapy and volumetric modulated arc therapy

Optimal time of tumour response evaluation and effectiveness of hypofractionated proton beam therapy for inoperable or recurrent hepatocellular carcinoma

“…In a recent meta-analysis [ 16 ], survival rates for charged particle therapy were increased compared with those for CRT but similar to those for SBRT, and toxicity tends to be lower for charged particle therapy compared with CRT and SBRT. Similarly, our previous study demonstrated that better dose localisation properties of protons compared with photons made it possible to more effectively spare normal liver tissue in PBT compared with RT with photons [ 31 ]. Although the present study included several unfavourable prognostic characteristics (e.g., recurrent tumours and advanced stage), 47 of 49 (95.9%) patients who had recurrent disease received post-PBT treatment to the PBT site and/or other sites; moreover, treatment-related toxicities were minimal, with no grade ≥3 toxicity.…”

“…Figure 1 illustrates the definition of target volumes. The gross tumour volume (GTV) included all detectable primary tumours as determined by contrast-enhanced AIP-CT images during the exhalation phase, and the clinical target volume (CTV) was regarded as GTV [ 6 – 8 , 10 , 31 , 32 ]. The gated internal target volume (ITV) was obtained by summing the GTVs in each CT image during the exhalation phases.…”

“…The prescribed dose of PTV was 66 GyE (EQD2, 91.3 GyE 10 ) in 10 fractions based on results of our previous [ 6 , 7 ] and other studies [ 29 , 33 ]. The details of the normal tissue constraints have been described previously [ 6 , 31 ]: the maximum dose to the spinal cord could not exceed 27 GyE; the relative volumes of the total and remaining normal liver that received doses of 27 GyE ( TL V27 and RNL V27) were below 60% and 50%, respectively; the absolute volumes of the oesophagus and stomach that received at least 37 GyE were ≤2 cm 3 ; and the absolute volumes of the small and large bowel that received at least 35 GyE were ≤2 cm 3 . At each treatment fraction, digital orthogonal fluoroscopy was used to position patient and to verify the isocenter, and irradiation was performed during the exhalation phase using RPM system.…”

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: Current Trends and Controversies

“… 84 A study by Kim et al showed similar dose reduction to the liver with a considerable reduction in liver volume receiving 5 to 45 Gy. 85 A University of Pennsylvania study by Gandhi et al showed that both tumor location and size were correlated with the dosimetric superiority of PBT-SBRT over photon-based SBRT. 86 Proton beam therapy generally provided dosimetric advantages in liver sparing for tumors >3 cm and located in the dome or central liver as well as for most tumors >5 cm.…”

Differential gene expression in primary fibroblasts induced by proton and cobalt-60 beam irradiation

“…Proton beam therapy is becoming increasingly available for cancer treatment. Proton beams deliver a more conformal dose distribution compared with conventional photon radiotherapy, resulting in diminished medium and low dose baths to normal tissue [1][2][3][4]. Protons deposit little dose in the entrance region, while maximum dose deposition is at the characteristic Bragg peak immediately before the protons halt, thus virtually avoiding any exit-dose [5].…”