Long-term outcomes of proton beam therapy in patients with previously untreated hepatocellular carcinoma

Proton Beam Therapy for Treating Patients with Hepatocellular Carcinoma with Major Portal Vein Tumor Invasion: A Single Center Retrospective Study

Hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) has a poor prognosis and is generally not indicated for surgery. Proton beam therapy (PBT) may offer an alternative treatment. In this study, long-term outcomes were examined in 116 patients (median age 66 years, 100 males) with HCC with advanced PVTT (Vp3 or Vp4) who received PBT from April 2008 to March 2018. Of these patients, 63 received PBT as definitive treatment and 53 as palliative treatment. The representative dose was 72.6 Gy (RBE) in 22 fractions. Eight patients died in follow-up, including 72 due to tumor progression. The 5-year overall survival (OS) rate was 18.0% (95% CI 9.8-26.2%) and the 5-year local control (LC) rate was 86.1% (74.9-97.3%). In multivariate analyses, performance status and treatment strategy were significantly associated with OS. The median follow-up period for survivors with definitive treatment was 33.5 (2-129) months, and the 5-year OS rate was 25.1% (12.9-37.3%) in these cases. The median survival time after definitive irradiation was >20 months. The 5-year OS rate was 9.1% (0-19.7%) for palliative irradiation. These results compare favorably with those of other therapies and suggest that PBT is a useful option for cases of HCC with advanced PVTT that cannot undergo surgery, with an expected survival benefit and good local control. Determining the optimal indication for this treatment is a future challenge.

Impact of iodinated oil in proton therapy on relative stopping power of liver post-cTACE

Objective. Conventional transarterial chemoembolization (cTACE) is a common treatment for hepatocellular carcinoma (HCC), often with unsatisfactory local controls. Combining cTACE with radiotherapy shows a promise for unresectable large HCC, with proton therapy preserving healthy liver tissue. However, the proton therapy benefits are subject to the accuracy of tissue relative stopping power (RSP) prediction. The RSP values are typically derived from computed tomography (CT) images using stoichiometric calibration. Lipiodol deposition significantly increases CT numbers in liver regions of post-cTACE. Hence, it is necessary to evaluate the accuracy of RSP in liver regions of post-cTACE.Approach. Liver, water, and iodinated oil samples were prepared. Some liver samples contained iodinated oil. The water equivalent path length (WEPL) of sample was measured through the pullbacks of spread-out Bragg peak (SOBP) depth-dose profiles scanned in a water tank with and without sample in the beam path. Measured RSP values were compared to estimated RSP values derived from the CT number based on the stoichiometric calibration method.Main results. The measured RSP of water was 0.991, confirming measurement system calibration. After removing the RSP contribution from container walls, the pure iodinated oil and liver samples had RSP values of 1.12 and 1.06, while the liver samples mixed with varying oil volumes (5 ml, 10 ml, 15 ml) showed RSP values of 1.05, 1.05 and 1.06. Using the stoichiometric calibration method, pure iodinated oil and liver samples had RSP values of 2.79 and 1.06. Liver samples mixed with iodinated oil (5 ml, 10 ml, 15 ml) had calculated RSP values of 1.21, 1.34, and 1.46. The RSP discrepancy reached 149.1% for pure iodinated oil.Significance.Iodinated oil notably raises CT numbers in liver tissue. However, there is almost no effect on its RSP value. Proton treatment of post-cTACE HCC patients can therefore be overshooting if no proper measures are taken against this specific effect.

Current perspectives on radiotherapy in hepatocellular carcinoma management: a comprehensive review

This review examines the transformative role of external beam radiotherapy (EBRT) in managing hepatocellular carcinoma (HCC), spotlighting the progression from traditional EBRT techniques to advanced modalities like intensity-modulated radiotherapy (RT), stereotactic body RT (SBRT), and innovative particle therapy, including proton beam therapy and carbon ion RT. These advancements have significantly improved the precision and efficacy of RT, marking a paradigm shift in the multimodal management of HCC, particularly in addressing complex cases and enhancing local tumor control. The review underscores the synergistic potential of integrating RT with other treatments like transarterial chemoembolization, systemic therapies such as sorafenib, and emerging immunotherapies, illustrating enhanced survival and disease control outcomes. The efficacy of RT is addressed for challenging conditions, including advanced HCC with macrovascular invasion, and RT modalities, like SBRT, are compared against traditional treatments like radiofrequency ablation for early-stage HCC. Additionally, the review accentuates the encouraging outcomes of particle therapy in enhancing local control and survival rates, minimizing treatment-related toxicity, and advocating for continued research and clinical trials. In conclusion, the integration of RT into multimodal HCC treatment strategies, coupled with the emergence of particle therapy, is crucial for advancing oncologic management, emphasizing the need for relentless innovation and personalized treatment approaches.

Role of Stereotactic Body Radiation Therapy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC)is a common type of liver cancer with a poor prognosis, especially in patients with advanced stages or underlying liver disease. While surgical resection, liver transplantation, and ablation therapies have traditionally been the mainstay of treatment for HCC, radiation therapy has become increasingly recognized as an effective alternative, particularly for those who are not surgical candidates. Stereotactic Body Radiation Therapy (SBRT) is a highly precise form of radiation therapy that delivers very high doses of radiation to the tumor while sparing surrounding healthy tissue. Several studies have reported favorable outcomes with SBRT in HCC treatment. Moreover, SBRT can be used to treat recurrent HCC after prior treatment, offering a potentially curative approach in select cases. While SBRT has demonstrated its efficacy and safety in treating HCC, future studies are needed to further investigate the potential role of SBRT in combination with other treatments for HCC.

Current evidence and the potential role of proton beam therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death, and external beam radiation therapy has emerged as a promising approach for managing HCC. Proton beam therapy (PBT) offers dosimetric advantages over X-ray therapy, with superior physical properties known as the Bragg peak. PBT holds promise for reducing hepatotoxicity and allowing safe dose-escalation to the tumor. It has been tried in various clinical conditions and has shown promising local tumor control and survival outcomes. A recent phase III trial demonstrated the non-inferiority of PBT in local tumor control compared to current standard radiofrequency ablation in early-stage HCC. PBT also tended to show more favorable outcomes compared to transarterial chemoembolization in the intermediate stage, and has proven effective in-field disease control and safe toxicity profiles in advanced HCC. In this review, we discuss the rationale, clinical studies, optimal indication, and future directions of PBT in HCC treatment.

Feasibility of additional radiotherapy in patients with advanced hepatocellular carcinoma treated with atezolizumab plus bevacizumab

BACKGROUND/AIM

Radiotherapy (RT) is an effective local treatment for hepatocellular carcinoma (HCC). However, whether additional RT is safe and effective in patients with advanced HCC receiving atezolizumab plus bevacizumab remains unclear. This retrospective cohort study aimed to evaluate the feasibility of additional RT in these patients.

METHODS

Between March and October 2021, we retrospectively analyzed seven patients with advanced HCC who received RT during treatment with atezolizumab plus bevacizumab. The median prescribed RT dose was 35 Gy (range, 33-66). Freedom from local progression (FFLP), progression-free survival (PFS), and overall survival (OS) after RT were analyzed.

RESULTS

The median follow-up duration after RT was 14.2 months (range, 10.0-18.6). Of the seven patients, disease progression was noted in six (85.7%), the sites of disease progression were local in two (28.6%), intrahepatic in four (57.1%), and extrahepatic in four (57.1%). The median time of FFLP was not reached, and PFS and OS times were 4.0 (95% confidence interval [CI], 3.6-4.5) and 14.8% (95% CI, 12.5-17.2) months, respectively. The 1-year FFLP, PFS, and OS rates were 60% (95% CI, 43.8-76.2), 0%, and 85.7% (95% CI, 75.9-95.5), respectively. Grade 3 or higher hematologic adverse events (AEs) were not observed, but grade 3 nonhematologic AEs unrelated to RT were observed in one patient.

CONCLUSIONS

The addition of RT may be feasible in patients with advanced HCC treated with atezolizumab plus bevacizumab. However, further studies are required to validate these findings.

Proton beam therapy for hepatocellular carcinoma with bile duct invasion

AIM

Hepatocellular carcinoma (HCC) with bile duct invasion (BDI) (BDIHCC) has a poor prognosis. Moreover, due to the paucity of reports, there is no consensus regarding optimal management of this clinical condition yet. The aim of this study was to clarify the efficacy and safety of proton beam therapy (PBT) for BDIHCC.

METHODS

Between 2009 and 2018, 15 patients with BDIHCC underwent PBT at our institution. The overall survival (OS), local control (LC), and progression-free survival (PFS) curves were constructed using the Kaplan-Meier method. Toxicities were assessed using the Common Terminology Criteria of Adverse Events version 4.0.

RESULTS

The median follow-up time was 23.4 months (range, 7.9-54.3). The median age was 71 years (range, 58-90 years). Many patients were Child A (n = 8, 53.3%) and most had solitary tumors (n = 11, 73.3%). Additionally, most patients had central type BDI (n = 11, 73%). The median tumor size was 4.0 cm (range, 1.5-8.0 cm). The 1-, 2-, and 3-year OS rates were 80.0%, 58.7% and 40.2%, respectively, and the corresponding LC and PFS rates were 93.3%, 93.3%, and 74.7% and 72.7%, 9.7%, and 0.0%, respectively. Acute grade 1/2 dermatitis (n = 7, 46.7%), and grades 2 (n = 1, 6.7%) and 3 (n = 1, 6.7%) cholangitis were observed. Late toxicities such as grade 3 gastric hemorrhage and pleural effusion were observed. No toxicities of grade 4 or higher were observed.

CONCLUSIONS

PBT was feasible with tolerable toxicities for the treatment of BDIHCC.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Proton Beam Therapy and Photon-Based Magnetic Resonance Image-Guided Radiation Therapy: The Next Frontiers of Radiation Therapy for Hepatocellular Carcinoma

External beam radiation therapy (EBRT) has increasingly been utilized in the treatment of hepatocellular carcinoma (HCC) due to technological advances with positive clinical outcomes. Innovations in EBRT include improved image guidance, motion management, treatment planning, and highly conformal techniques such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT). Moreover, proton beam therapy (PBT) and magnetic resonance image-guided radiation therapy (MRgRT) have expanded the capabilities of EBRT. PBT offers the advantage of minimizing low- and moderate-dose radiation to the surrounding normal tissue, thereby preserving uninvolved liver and allowing for dose escalation. MRgRT provides the advantage of improved soft tissue delineation compared to computerized tomography (CT) guidance. Additionally, MRgRT with online adaptive therapy is particularly useful for addressing motion not otherwise managed and reducing high-dose radiation to the normal tissue such as the stomach and bowel. PBT and online adaptive MRgRT are emerging technological advancements in EBRT that may provide a significant clinical benefit for patients with HCC.

2022 KLCA-NCC Korea Practice Guidelines for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Long-Term Results of Proton Therapy for Hepatocellular Carcinoma Using Four-Dimensional Computed Tomography Planning without Fiducial Markers

We report here the long-term results of marker-less respiratory-gated proton therapy (PT), without fiducial markers for hepatocellular carcinoma (HCC), which was planned using a four-dimensional computed tomography technique. Local tumor control (LTC) and overall survival (OS) were estimated using the Kaplan-Meier method. Toxicity was graded per CTCAE v5.0. Patients (n = 105; median age 73 years, range 38-90 years) with 128 lesions were treated. The median radiation dose was 66 gray relative biological effectiveness (GyRBE) (range, 52.8-82.5 GyRBE) delivered in 2.0 to 6.6 GyRBE fractions, depending on lesion volume, the involved liver, and the patient's condition. The median follow-up of surviving patients was 63 months (range, 1-126 months), and the 5-year LTC and OS rates were 93.2% and 40.4%, respectively. Univariate and multivariate analyses identified tumors near the gastrointestinal tract as an independent risk factor for local recurrence and revealed that hepatic reserve, tumor stage, performance status, operability, sex, and portal vein thrombosis were independent risk factors for OS. Acute and late treatment-related grade 3 toxicities were experienced by eight patients (7.6%). Adverse events ≥ grade 4 were not evident. Marker-less respiratory-gated PT for HCC is a safe and effective treatment without severe complications.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Proton Beam Therapy for Treatment-Naïve Hepatocellular Carcinoma and Prognostic Significance of Albumin-Bilirubin (ALBI) Grade

To evaluate the efficacy of proton beam therapy (PBT) as an initial treatment in treatment-naïve hepatocellular carcinoma (HCC) patients and to assess the prognostic significance of albumin-bilirubin (ALBI) grade, 46 treatment-naïve HCC patients treated with PBT were analyzed. The ALBI grade distribution was grade 1 in 11 (23.9%) patients, grade 2 in 34 (73.9%) patients, and grade 3 in 1 (2.2%) patient. The median duration of follow-up was 56.5 months (95% confidence interval [CI], 48.2−64.7). Among the 46 patients, disease progression was observed in 23 (50%) patients: local progression in 3 (6.5%) patients; intrahepatic progression in 22 (47.8%); and extrahepatic progression in 5 (10.9%). The 5-year freedom from local progression (FFLP), progression-free survival (PFS), and overall survival (OS) rates were 92.7% (95% CI, 84.7−100.7), 43.3% (95% CI, 28.2−58.4), and 69.2% (95% CI, 54.9−83.5), respectively. In multivariate analysis, there were no independent factors for FFLP (p > 0.05 each), but tumor stage and ALBI grade were independent factors for PFS and OS (p < 0.05 each). PBT could result in comparable OS in treatment-naïve HCC patients to other recommended first-line treatments, and ALBI grade, in addition to tumor stage, could be useful for predicting OS.

The American Brachytherapy Society consensus statement for permanent implant brachytherapy using Yttrium-90 microsphere radioembolization for liver tumors

PURPOSE

To develop a multidisciplinary consensus for high quality multidisciplinary implementation of brachytherapy using Yttrium-90 (90Y) microspheres transarterial radioembolization (90Y TARE) for primary and metastatic cancers in the liver.

METHODS AND MATERIALS

Members of the American Brachytherapy Society (ABS) and colleagues with multidisciplinary expertise in liver tumor therapy formulated guidelines for 90Y TARE for unresectable primary liver malignancies and unresectable metastatic cancer to the liver. The consensus is provided on the most recent literature and clinical experience.

RESULTS

The ABS strongly recommends the use of 90Y microsphere brachytherapy for the definitive/palliative treatment of unresectable liver cancer when recommended by the multidisciplinary team. A quality management program must be implemented at the start of 90Y TARE program development and follow-up data should be tracked for efficacy and toxicity. Patient-specific dosimetry optimized for treatment intent is recommended when conducting 90Y TARE. Implementation in patients on systemic therapy should account for factors that may enhance treatment related toxicity without delaying treatment inappropriately. Further management and salvage therapy options including retreatment with 90Y TARE should be carefully considered.

CONCLUSIONS

ABS consensus for implementing a safe 90Y TARE program for liver cancer in the multidisciplinary setting is presented. It builds on previous guidelines to include recommendations for appropriate implementation based on current literature and practices in experienced centers. Practitioners and cooperative groups are encouraged to use this document as a guide to formulate their clinical practices and to adopt the most recent dose reporting policies that are critical for a unified outcome analysis of future effectiveness studies.

Proton Therapy in the Management of Hepatocellular Carcinoma

Simple Summary

Radiation therapy is among the locoregional therapy modalities used to treat unresectable or medically inoperable hepatocellular carcinoma (HCC). Proton radiation therapy plays a major role in the treatment of HCC, especially when liver toxicity is a concern. The aim of this review is to provide a concise and comprehensive summary on the use of proton therapy in the management of HCC.

Abstract

Proton radiation therapy plays a central role in the treatment of hepatocellular carcinoma (HCC). Because of the near-zero exit dose and improved sparing of normal liver parenchyma, protons are being used even in challenging scenarios, including larger or multifocal liver tumors, and those associated with vascular tumor thrombus. There is a mounting level of evidence that suggests that protons are superior to photons in terms of survival and toxicity outcomes, specifically the progression to liver failure. A randomized controlled trial comparing protons to photons is currently underway to verify this hypothesis.

Hypofractionation in Hepatocellular Carcinoma - The Effect of Fractionation Size

The use of stereotactic body radiotherapy (SBRT) in hepatocellular carcinoma (HCC) has increased over the years. Several prospective studies have demonstrated its safety and efficacy, and randomised trials are underway. The advancement in technology has enabled the transition from three-dimensional conformal radiotherapy to highly focused SBRT. Liver damage is the primary limiting toxicity with radiation, with the incidence of grade 3 varying from 0 to 30%. The reported radiotherapy fractionation schedule for HCC, and in practice use, ranges from one to 10 fractions, based on clinician preference and technology available, tumour location and tumour size. This review summarises the safety and efficacy of various SBRT fractionation schedules for HCC.

External Beam Radiation Therapy for Primary Liver Cancers: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations for the indications and technique-dose of external beam radiation therapy (EBRT) in hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHC).

METHODS

The American Society for Radiation Oncology convened a task force to address 5 key questions focused on the indications, techniques, and outcomes of EBRT in HCC and IHC. This guideline is intended to cover the definitive, consolidative, salvage, preoperative (including bridge to transplant), and adjuvant settings as well as palliative EBRT for symptomatic primary lesions. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Strong recommendations are made for using EBRT as a potential first-line treatment in patients with liver-confined HCC who are not candidates for curative therapy, as consolidative therapy after incomplete response to liver-directed therapies, and as a salvage option for local recurrences. The guideline conditionally recommends EBRT for patients with liver-confined multifocal or unresectable HCC or those with macrovascular invasion, sequenced with systemic or catheter-based therapies. Palliative EBRT is conditionally recommended for symptomatic primary HCC and/or macrovascular tumor thrombi. EBRT is conditionally recommended as a bridge to transplant or before surgery in carefully selected patients. For patients with unresectable IHC, consolidative EBRT with or without chemotherapy should be considered, typically after systemic therapy. Adjuvant EBRT is conditionally recommended for resected IHC with high-risk features. Selection of dose-fractionation regimen and technique should be based on disease extent, disease location, underlying liver function, and available technologies.

CONCLUSIONS

The task force has proposed recommendations to inform best clinical practices on the use of EBRT for HCC and IHC with strong emphasis on multidisciplinary care. Future studies should focus on further defining the role of EBRT in the context of liver-directed and systemic therapies and refining optimal regimens and techniques.

A Phase 2 Study of Image-Guided Proton Therapy for Operable or Ablation-Treatable Primary Hepatocellular Carcinoma

PURPOSE

Because most previous data on proton therapy for hepatocellular carcinoma (HCC) were retrospectively collected from inoperable or previously treated cases, our aim was to evaluate the outcome of image-guided proton therapy (IGPT) for operable or radiofrequency ablation-treatable primary HCC.

METHODS AND MATERIALS

This phase 2 study prospectively investigated the efficacy and safety of IGPT and quality of life (QoL) after IGPT for operable/ablatable HCC. The primary endpoint was overall survival, and the secondary endpoints were local control, incidence of grade ≥3 adverse events, and changes in QoL. Toxicities were evaluated with Common Terminology Criteria for Adverse Events, version 4.0. QoL scores were assessed with European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, version 3.0, and Quality of Life Questionnaire-Hepatocellular Carcinoma/Primary Liver Cancer Module. IGPT was performed using respiratory-gated techniques.

RESULTS

Forty-five patients (median age: 68 years; range, 36-80 years) were enrolled between June 2013 and February 2016; 38 were considered operable and 14 were indicated for radiofrequency ablation. The major underlying liver diseases were hepatitis B (n = 16), hepatitis C (n = 13), alcoholic hepatitis (n = 3), and nonalcoholic fatty liver disease (n = 13). The Child-Pugh score was A5 in 32 patients, A6 in 9 patients, and B7 in 4 patients. Thirty-seven patients with a peripherally located tumor were given 66 Gy relative biological effectiveness in 10 fractions, and 8 patients with a centrally located tumor received 72.6 Gy relative biological effectiveness in 22 fractions. The median follow-up period of surviving patients was 60 months (range, 42-75 months). Two- and 5-year overall survival rates were 84% (95% confidence interval [CI], 74%-95%) and 70% (95% CI, 56%-84%), respectively, and local control rates were 95% (95% CI, 89%-100%) and 92% (95% CI, 84%-100%), respectively. Grade 3 radiation-induced liver disease was observed in 1 patient. No significant changes were noted in QoL scores 1 year after treatment, except for body image.

CONCLUSIONS

Although the primary endpoint did not meet statistical significance as planned in the study design, IGPT is a safe and effective treatment for solitary primary HCC and may become a treatment option.

Frontiers of therapy for hepatocellular carcinoma

The incidence of hepatocellular carcinoma continues to increase worldwide. Fortunately, there have been notable recent advances in locoregional and systemic therapy. In this current review, we will highlight these new developments and future directions of hepatocellular carcinoma treatment and address the importance of a multidisciplinary approach to treatment.

SBRT for HCC: Overview of technique and treatment response assessment

Stereotactic body radiation therapy (SBRT) is an emerging locoregional treatment (LRT) modality used in the management of patients with hepatocellular carcinoma (HCC). The decision to treat HCC with LRT is evaluated in a multidisciplinary setting, and the specific LRT chosen depends on the treatment intent, such as bridge-to-transplant, down-staging to transplant, definitive/curative treatment, and/or palliation, as well as underlying patient clinical factors. Accurate assessment of treatment response is necessary in order to guide clinical management in these patients. Patients who undergo LRT need continuous imaging evaluation to assess treatment response and to evaluate for recurrence. Thus, an accurate understanding of expected post-SBRT imaging findings is critical to avoid misinterpreting normal post-treatment changes as local progression or viable tumor. SBRT-treated HCC demonstrates unique imaging findings that differ from HCC treated with other forms of LRT. In particular, SBRT-treated HCC can demonstrate persistent APHE and washout on short-term follow-up imaging. This brief review summarizes current evidence for the use of SBRT for HCC, including patient population, SBRT technique and procedure, tumor response assessment on contrast-enhanced cross-sectional imaging with expected findings, and pitfalls in treatment response evaluation.

A preliminary study of hepatocellular carcinoma post proton beam therapy using MRI as an early prediction of treatment effectiveness

Purpose

To demonstrate the feasibility of magnetic resonance imaging (MRI) for early prediction of proton beam therapy (PBT) effectiveness in hepatocellular carcinoma (HCC).

Methods

Clinical data of the HCC patients without regional lymph node involvement or distant metastasis who received PBT at this institution between 2014 and 2017 were reviewed. A total of 43 patients were included. Tumor regression pattern after PBT were examined on the basis of follow-up duration. The variables were compared between patients with and without early tumor regression (ETR).

Results

The median follow-up duration was 40 months (range, 9–62 months). The cumulative overall survival rate at 6 months, 1 years and 5 years was 100%, 88.4%, 63.4%, respectively. Child-Pugh class A, local tumor control (LTC), complete response (CR), and ETR were significantly associated with overall survival (p < 0.05 each). Of 43 patients, 25 patients (58.1%) reached CR in the PBT-irradiated region. Twelve patients (27.9%) had a partial response and 3 patients (7.0%) had a stationary disease. Three patients (7.0%) developed in-field progression. The LTC rate at 5 years was 93.0%. Of the 25 patients who achieved a CR in the PBT-irradiated region, the median time to CR was 5 months (range, 1–19 months). Twenty-two patients (51.2%) showed ETR of the HCC, while 21 patients (48.8%) showed non-ETR. A significant association was observed between ETR and CR of the HCC after PBT (p < 0.001).

Conclusion

The post-PBT MRI follow-up at 3 months is helpful for monitoring therapeutic response. ETR of the HCC predicted a higher rate of CR and was associated with overall survival, which provides more accurate clinical management.

Anti-Hepatoma Compound Determination by the Method of Spectrum Effect Relationship, Component Knock-Out, and UPLC-MS2 in Scheflera heptaphylla (L.)Frodin Harms and Its Mechanism

Scheflera heptaphylla (L.)Frodin, a kind of Traditional Chinese Medicine, is commonly used in anti-inflammatory, analgesic, anti-viral, anti-tumor, and hemostasis. This study aimed to determine the anti-hepatoma components and its mechanism from the leaves of S. heptaphylla. The spectrum-effect relationships were analyzed by the method of Partial least squares, indicating that P1, P2, and P10 were positively correlated to inhibitory activity of Huh7 cells. Whereas others were negatively correlated. The technologies of component knock-out and UPLC-MS² were used to determine compounds as 3,4-Dicaffeoylquinic acid (P6), 3,5-Dicaffeoylquinic acid (P7), 3α-Hydroxy-lup-20(29)-ene-23,28-dioic acid (P10, named Compound A). The results forecasted that Compound A had the best correlation with inhibitory activity. The effects of Compound A on the activities of human hepatoma cells (Huh7, SMMC-7721, HepG 2) and normal hepatocytes (L0-2, Chang liver) were evaluated. Cell apoptosis was observed with inverted microscope and flow cytometer. In addition, the proteins, related to apoptosis, were detected by Western blot. The results showed that Compound A (400 nM) could significantly inhibit the activity of three hepatoma cells (P < 0.001) with slight toxicity to normal hepatocytes, and the IC₅₀ values were 285.3 and 315.1 nM, respectively, which were consistent with the prediction of spectrum-effect relationships. After treatment with Compound A, the number of hepatoma cells decreased significantly. And the apoptosis rate of Huh7 cells increased significantly (P < 0.001) in Compound A (200, 400 nM) groups, SMMC-7721 and HepG 2 were directly necrotic. Compound A groups could significantly improve the level of intracellular reactive oxygen species (ROS) (P < 0.05, P < 0.001) in Huh7 with no effect on normal hepatocytes. The content of apoptotic protein (Bax and Bim) in mitochondria was significantly increased in Compound A groups (P < 0.001). On the contrary, the content of anti-apoptotic protein (Bcl-xL and Mcl-1) decreased significantly (P < 0.001). These results demonstrated that Compound A was the main anti-hepatoma active component in the S. heptaphylla leaves. It achieved the effect of promoting apoptosis of Huh7 cells by regulating the levels of ROS and Bcl-2 family protein in mitochondrial apoptosis pathway.

Clinical Outcomes of Patients With Unresectable Cholangiocarcinoma Treated With Proton Beam Therapy

OBJECTIVE

To investigate the clinical outcomes and failure patterns of patients with unresectable cholangiocarcinoma (CC) who had been treated with proton beam therapy (PBT).

METHODS

The authors retrospectively examined 30 patients with unresectable CC who had undergone PBT between November 2015 and December 2017. Survival curves were plotted with the Kaplan-Meier method. Independent predictors of survival were identified by multivariate Cox proportional hazard regression analyses. Complications were assessed using the Common Terminology Criteria for Adverse Events v4.0.

RESULTS

The median tumor size was 7 cm. Seventeen patients (56.7%) had regional lymph node metastases. The median radiation dose was 72.6 cobalt gray equivalents, and 23 patients (76.7%) received concurrent chemotherapy. The 1-year local control, regional control, and distant metastases-free rates were 88%, 86%, and 68%, respectively. The median overall survival and progression-free survival were 19.3 and 10.4 months, respectively. The median jaundice-free survival was 13 months, with a 1-year biliary tract infection (BTI)-free rate of 58%. Patients who received concurrent chemotherapy had a better median progression-free survival (12.1 vs. 4.7 mo). The most common form of acute toxicity from PBT was acute skin reactions which were rarely severe (grade III: 7% of patients). Three and 2 patients had grade III-IV toxicities and radiation-induced liver disease. There were no deaths caused by PBT or concurrent chemotherapy.

CONCLUSIONS

PBT is clinically useful in patients with unresectable CC, even in the presence of large tumors or regional nodal metastases. Its use may induce durable symptom relief, without increasing acute or late toxicity.

Transitions of Liver and Biliary Enzymes during Proton Beam Therapy for Hepatocellular Carcinoma

Proton beam therapy (PBT) is a curative treatment for hepatocellular carcinoma (HCC), because it can preserve liver function due to dose targeting via the Bragg peak. However, the degree of direct liver damage by PBT is unclear. In this study, we retrospectively analyzed liver/biliary enzymes and total bilirubin (T-Bil) as markers of direct liver damage during and early after PBT in 300 patients. The levels of these enzymes and bilirubin were almost stable throughout the treatment period. In patients with normal pretreatment levels, aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), and T-Bil were abnormally elevated in only 2 (1.2%), 1 (0.4%), 0, 2 (1.2%), and 8 (3.5%) patients, respectively, and in 8 of these 13 patients (61.5%) the elevations were temporary. In patients with abnormal pretreatment levels, the levels tended to decrease during PBT. GGT and T-Bil were elevated by 1.62 and 1.57 times in patients who received 66 Gy (RBE) in 10 fractions and 74 Gy (RBE) in 37 fractions, respectively, but again these changes were temporary. These results suggest that direct damage to normal liver caused by PBT is minimal, even if a patient has abnormal pretreatment enzyme levels.

Phase II Study of Hypofractionated Proton Beam Therapy for Hepatocellular Carcinoma

Background: Proton beam has an excellent depth dose distribution due to its unique physical properties, and thus proton beam therapy (PBT) has been tried and showed promising outcomes in hepatocellular carcinoma (HCC). The purpose of this phase II study is to evaluate the efficacy of hypofractionated PBT in HCC.

Methods: The eligibility criteria for this study were as follows: patients with HCC lesion(s) who were failed after, were difficult to treat with, or refused to other local treatments; tumor size and number of ≤7 and ≤2 cm, respectively, and HCC lesion(s) of ≥2 cm from gastrointestinal organs; Child–Pugh score of ≤7; Eastern Cooperative Oncology Group performance status ≤1; and age ≥18 years. The prescribed dose of PBT was 70 Gy equivalent in 10 fractions. The primary endpoint was 3-year local progression-free survival (LPFS) rate.

Results: Forty-five patients were prospectively enrolled, and there were 35 men and 10 women with a median age of 63 years (range, 46–78 years). Thirty-seven patients had recurrent and/or residual disease, and eight patients had treatment-naive disease. All patients received the planned treatments without treatment interruption, and grade ≥3 acute toxicity did not occur. The median follow-up duration was 35.1 months (range, 11.2–56.3 months) and local progression occurred in two patients (8.7%). The 3-year rates of LPFS and overall survival (OS) were 95.2% (95% confidence interval [CI], 89.1%−100%) and 86.4% (95% CI, 72.9–99.9%), respectively.

Conclusion: Hypofractionated PBT showed promising LPFS and OS, and further studies are warranted to compare PBT with other local modalities.

Proton beam therapy for liver cancers

Proton beam therapy (PBT) delivers less dose to nearby normal organs compared to X-ray therapy (XRT), which is particularly relevant for treating liver cancers given that both mean and low liver dose are among the most significant predictors of radiation induced liver disease (RILD). High-dose PBT has been shown to achieve excellent long-term tumor control with minimal toxicity in hepatocellular carcinoma (HCC) patients. Increasing data support ablative PBT for patients with unresectable cholangiocarcinoma or liver metastases, especially those with larger tumors not suitable for XRT.

Indicator for local recurrence of hepatocellular carcinoma after proton beam therapy: analysis of attenuation difference between the irradiated tumor and liver parenchyma on contrast enhancement CT

OBJECTIVES

We aimed to identify dynamic CT features that can be used for prediction of local recurrence of hepatocellular carcinoma (HCC) after proton beam therapy (PBT).

METHODS

We retrospectively retrieved CT scans of patients with PBT-treated HCC, taken between January 2004 and December 2016. 17 recurrent lesions and 34 non-recurrent lesions were retrieved. The attenuation difference between irradiated tumor and irradiated parenchyma (AD_HCC-IP) was compared in the two groups by using the Mann-Whitney U test. Cut-off value of AD_HCC-IP was estimated by using the Youden index.

RESULTS

The follow-up time after PBT initiation ranged from 374 to 2402 days (median, 1069 days) in recurrent lesions, and 418 to 2923 days (median, 1091.5 days) in non-recurrent lesions (p = 0.892). The time until appearance of local recurrence after PBT initiation ranged from 189 to 2270 days (median, 497 days). AD_HCC-IP of recurrent lesions [mean, -21.8 Hounsfield units (HU); from -95 to -31 HU] was significantly greater than that of non-recurrent lesions (mean, -51.7 HU; from -117 to -12 HU) at 1-2 years in portal venous phase (p = 0.039). 5-year local tumor control rates were 0.93 and 0.56 in lesions with AD_HCC-IP at 1-2 years in PVP < -55 and ≥ -55 HU, respectively.

CONCLUSION

The attenuation difference between irradiated HCC and irradiated liver parenchyma in portal venous phase at 1-2 years after PBT can predict long-term local recurrence of HCC after treatment.

ADVANCES IN KNOWLEDGE

We identified a cut-off value for contrast enhancement of HCC after PBT that could predict future local recurrence.

A comparison of the outcomes between surgical resection and proton beam therapy for single primary hepatocellular carcinoma

PURPOSE

There are many treatment choices for hepatocellular carcinoma (HCC), one of which is proton beam therapy (PBT). The purpose of this study was to compare surgical resection (SR) and PBT to clarify the prognostic factors for operable HCC based on a single institution's database.

METHODS

Patients with single primary nodular HCC ≤ 100 mm without vessel invasion on pretreatment imaging were divided into the SR group and PBT group. In the PBT group, the patients with unresectable HCC due to their liver function and/or performance status were excluded.

RESULTS

There were 314 and 31 patients who underwent SR and PBT, respectively. The median survival time in the SR group was significantly better than in the PBT group (104.1 vs. 64.6 months, p = 0.008). Regarding the relapse-free survival (RFS), there was no significant difference between the SR and PBT groups (33.8 vs. 14.0 months, p = 0.099).

CONCLUSION

The RFS was comparable between the PBT and SR groups. However, the PBT group had a significantly worse overall survival than the SR group. SR may therefore be favorable as an initial treatment for HCC compared to PBT.

A global view of hepatocellular carcinoma: trends, risk, prevention and management

Hepatocellular carcinoma (HCC) is the fourth most common cause of cancer-related death worldwide. Risk factors for HCC include chronic hepatitis B and hepatitis C, alcohol addiction, metabolic liver disease (particularly nonalcoholic fatty liver disease) and exposure to dietary toxins such as aflatoxins and aristolochic acid. All these risk factors are potentially preventable, highlighting the considerable potential of risk prevention for decreasing the global burden of HCC. HCC surveillance and early detection increase the chance of potentially curative treatment; however, HCC surveillance is substantially underutilized, even in countries with sufficient medical resources. Early-stage HCC can be treated curatively by local ablation, surgical resection or liver transplantation. Treatment selection depends on tumour characteristics, the severity of underlying liver dysfunction, age, other medical comorbidities, and available medical resources and local expertise. Catheter-based locoregional treatment is used in patients with intermediate-stage cancer. Kinase and immune checkpoint inhibitors have been shown to be effective treatment options in patients with advanced-stage HCC. Together, rational deployment of prevention, attainment of global goals for viral hepatitis eradication, and improvements in HCC surveillance and therapy hold promise for achieving a substantial reduction in the worldwide HCC burden within the next few decades.

Angiographic Findings in Patients with Hepatocellular Carcinoma Previously Treated Using Proton Beam Therapy

Given the growing interest in using proton beam therapy (PBT) for hepatocellular carcinoma (HCC), it is possible that transarterial chemoembolization (TACE) could be used for selected patients who have previously undergone PBT. However, these cases can be technically challenging to treat and require appropriate preparation. Thus, we aimed to identify angiographic findings in this setting. We retrospectively identified 31 patients (28 men and 3 women, mean age: 69 years, range: 43–84 years) who underwent hepatic angiography plus TACE or transarterial infusion chemotherapy (TAI) for HCC that recurred after PBT (July 2007 to June 2018). We discovered four angiographic findings, which we speculate were related to the previous PBT. 18 patients experienced recurrence in the irradiated field, and 13 patients experienced recurrence outside the irradiated field. 29 patients underwent TACE and only 2 patients underwent TAI. The mean number of previous PBT treatments was 1.3 ± 0.6 (range: 1–4). The median interval from the earliest PBT treatment to hepatic angiography was 559 days (range: 34–5,383 days), and the median interval from the latest PBT treatment to hepatic angiography was 464 days (range: 34–5,383 days). Abnormal staining of the irradiated liver parenchyma was observed in 22 patients, which obscured the angiographic tumor staining in 4 patients. Development of a tortuous tumor feeder vessel was observed in 13 patients. Development of an extrahepatic collateral pathway was observed in 7 patients. Development of an arterioportal or arteriovenous shunt was observed in 4 patients. Based on these findings, we conclude that PBT was associated with various angiographic findings during subsequent transarterial chemotherapy for recurrent HCC, and familiarity with these findings will be important in developing appropriate treatment plans.

2018 Korean Liver Cancer Association-National Cancer Center Korea Practice Guidelines for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer globally and the fourth most common cancer in men in Korea, where the prevalence of chronic hepatitis B infection is high in middle-aged and elderly patients. These practice guidelines will provide useful and constructive advice for the clinical management of patients with HCC. A total of 44 experts in hepatology, oncology, surgery, radiology, and radiation oncology in the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2014 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions.

Rethinking the Role of Radiation Therapy in the Treatment of Unresectable Hepatocellular Carcinoma: A Data Driven Treatment Algorithm for Optimizing Outcomes

Hepatocellular carcinoma (HCC) is the second most common cause of cancer death worldwide, with a majority of HCC patients not suitable for curative therapies. Approximately 70% of initially diagnosed patients cannot undergo surgical resection or transplantation due to locally advanced disease, poor liver function/underlying cirrhosis, or additional comorbidities. Local therapeutic options for patients with unresectable HCC, who are not suitable for thermal ablation, include transarterial embolization (bland, chemoembolization, radioembolization) and/or external beam radiation therapy (EBRT). Regarding EBRT specifically, technological advancements provide a means for safe and effective radiotherapy delivery in a wide spectrum of HCC patients. In multiple prospective studies, EBRT delivery in a variety of different fractionation schemes or in combination with transcatheter arterial chemoembolization (TACE) demonstrate improved outcomes, particularly with combination therapy. The Barcelona Clinic Liver Cancer classification provides a framework for treatment selection; however, given the growing complexity of treatment strategies, this classification system tends to simplify decision-making. In this review, we discuss the current literature regarding unresectable HCC and propose a modified treatment algorithm that emphasizes the role of radiation therapy for Child-Pugh score A or B patients with ≤3 nodules measuring >3 cm, multinodular disease or portal venous thrombosis.

Consensus Report From the Miami Liver Proton Therapy Conference

An international group of 22 liver cancer experts from 18 institutions met in Miami, Florida to discuss the optimal utilization of proton beam therapy (PBT) for primary and metastatic liver cancer. There was consensus that PBT may be preferred for liver cancer patients expected to have a suboptimal therapeutic ratio from XRT, but that PBT should not be preferred for all patients. Various clinical scenarios demonstrating appropriateness of PBT vs. XRT were reviewed.

2018 Korean Liver Cancer Association-National Cancer Center Korea Practice Guidelines for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer globally and the fourth most common cancer in men in Korea, where the prevalence of chronic hepatitis B infection is high in middle-aged and elderly patients. These practice guidelines will provide useful and constructive advice for the clinical management of patients with HCC. A total of 44 experts in hepatology, oncology, surgery, radiology and radiation oncology in the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2014 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions.

Does Risk-Adapted Proton Beam Therapy Have a Role as a Complementary or Alternative Therapeutic Option for Hepatocellular Carcinoma?

To evaluate the role of risk-adapted proton beam therapy (PBT) in hepatocellular carcinoma (HCC) patients, a total of 243 HCC patients receiving risk-adapted PBT with three dose-fractionation regimens (regimen A [n = 40], B [n = 60], and C [n = 143]) according to the proximity of their gastrointestinal organs (<1 cm, 1–1.9 cm, and ≥2 cm, respectively) were reviewed: The prescribed doses to planning target volume 1 (PTV1) were 50 gray equivalents (GyE) (EQD2 [equivalent dose in 2 Gy fractions], 62.5 GyE₁₀), 60 GyE (EQD2, 80 GyE₁₀), and 66 GyE (EQD2, 91.3 GyE₁₀) in 10 fractions, respectively, and those of PTV2 were 30 GyE (EQD2, 32.5 GyE₁₀) in 10 fractions. In all patients, the five-year local recurrence-free survival (LRFS) and overall survival (OS) rates were 87.5% and 48.1%, respectively, with grade ≥3 toxicity of 0.4%. In regimens A, B, and C, the five-year LRFS and OS rates were 54.6%, 94.7%, and 92.4% (p < 0.001), and 16.7%, 39.2%, and 67.9% (p < 0.001), respectively. The five-year OS rates of the patients with the Modified Union for International Cancer Control (mUICC) stages I, II, III, and IVA and Barcelona Clinic Liver Cancer (BCLC) stages A, B, and C were 69.2%, 65.4%, 43.8%, and 26.6% (p < 0.001), respectively, and 65.1%, 40%, and 32.2% (p < 0.001), respectively. PBT could achieve promising long-term tumor control and have a potential role as a complementary or alternative therapeutic option across all stages of HCC.

Transient increases in serum α fetoprotein and protein induced by vitamin K antagonist II levels following proton therapy does not necessarily indicate progression of hepatocellular carcinoma

Transient increases in α-fetoprotein (AFP) and protein induced by vitamin K antagonist II (PIVKA-II), so-called flares, are frequently observed after treatment of hepatocellular carcinoma (HCC). In the present study, changes in AFP and PIVKA-II levels after proton therapy (PT), and the relationship between the flare phenomenon and clinical response were investigated. In 82 patients with stage I/II HCC (59 with no recurrence and 23 with out-of-field recurrence within 1 year), serum AFP and PIVKA-II levels were measured at 1, 3, 6, 9 and 12 months post-PT. AFP and PIVKA-II flares were defined as a >20% increase from the preceding serum level above 20 ng/ml (AFP) or 40 mAU/ml (PIVKA-II), followed by a >20% drop. Among the 59 patients with no recurrence, 3 (5.1%) had an AFP flare, while 23 (39%) had a PIVKA-II flare. The median time to AFP and PIVKA-II flare peaks was 1 and 6 months, respectively. In 4 patients, PIVKA-II flares were observed twice during follow-up. In 1 patient, AFP and PIVKA-II flares were observed simultaneously at 1 month post-PT. The PIVKA-II level pre-PT was significantly higher in the PIVKA-II flare-positive group compared with that in the flare-negative group (P=0.015, odds ratio 4.3, 95% confidence interval, 1.3-14.0). In the 23 patients with out-of-field recurrence, the median increase rate of PIVKA-II (203%) was higher than that in the PIVKA-II-flare-positive group (111%, P=0.035) and the time to recurrence (median, 9 months) was longer than the time to peak AFP level (1 month) in the AFP-flare-positive group (P=0.033). There was no significant association between flares and clinical response. Increases in AFP and PIVKA-II levels following PT should be assessed with caution to avoid misinterpretation of therapeutic outcome.

Proton beam therapy for cancer in the era of precision medicine

Precision radiotherapy, which accurately delivers the dose on a tumor and confers little or no irradiation to the surrounding normal tissue and organs, results in maximum tumor control and decreases the toxicity to the utmost extent. Proton beam therapy (PBT) provides superior dose distributions and has a dosimetric advantage over photon beam therapy. Initially, the clinical practice and study of proton beam therapy focused on ocular tumor, skull base, paraspinal tumors (chondrosarcoma and chordoma), and unresectable sarcomas, which responded poorly when treated with photon radiotherapy. Then, it is widely regarded as an ideal mode for reirradiation and pediatrics due to reducing unwanted side effects by lessening the dose to normal tissue. During the past decade, the application of PBT has been rapidly increasing worldwide and gradually expanding for the treatment of various malignancies. However, to date, the role of PBT in clinical settings is still controversial, and there are considerable challenges in its application. We systematically review the latest advances of PBT and the challenges for patient treatment in the era of precision medicine.

Proton Beam Therapy and Carbon Ion Radiotherapy for Hepatocellular Carcinoma

Charged particle therapy with proton beam therapy (PBT) and carbon ion radiotherapy (CIRT) has emerged as a promising radiation modality to minimize radiation hepatotoxicity while maintaining high rates of tumor local control. Both PBT and CIRT deposit the majority of their dose at the Bragg peak with little to no exit dose, resulting in superior sparing of normal liver tissue. CIRT has an additional biological advantage of increased relative biological effectiveness, which may allow for increased hypofractionation regimens. Retrospective and prospective studies have demonstrated encouragingly high rates of local control and overall survival and low rates of hepatotoxicity with PBT and CIRT. Ongoing randomized trials will evaluate the value of PBT over photons and other standard liver-directed therapies and future randomized trials are needed to assess the value of CIRT over PBT.

Proton beam therapy in apneic oxygenation treatment of an unresectable hepatocellular carcinoma: A case report and review of literature

Presented here is the clinical course of a 63-year-old patient with a central, large and unresectable hepatocellular carcinoma (HCC) with liver metastases and tumor invasion of the portal and hepatic veins. After the tumor had been diagnosed, the patient was immediately treated with proton beam therapy (PBT), at a total dose of 60 Gy (relative biological effectiveness) in 20 fractions administered within 4 wk. To manage the respiratory movements, at the Rinecker Proton Therapy Center, apneic oxygenation was given daily, under general anesthesia. The patient tolerated both the PBT and general anesthesia very well, and did now show any signs of acute or late toxicity. The treatment was followed by constant reductions in the tumor marker alpha-fetoprotein and the cholestatic parameters gamma-glutamyltransferase and alkaline phosphatase. The patient commenced an adjuvant treatment with sorafenib, given at 6-wk intervals, after the PBT. Follow-up with regular magnetic resonance imaging has continued for 40 mo so far, demonstrating remarkable shrinkage of the HCC (maximal diameter dropping from approximately 13 cm to 2 cm). To date, the patient remains free of tumor recurrence. PBT served as a safe and effective treatment method for an unresectable HCC with vascular invasion.

Respiratory-gated Proton Beam Therapy for Hepatocellular Carcinoma Adjacent to the Gastrointestinal Tract without Fiducial Markers

The efficacy of proton beam therapy (PBT) for hepatocellular carcinoma (HCC) has been reported, but insertion of fiducial markers in the liver is usually required. We evaluated the efficacy and toxicity of respiratory-gated PBT without fiducial markers for HCC located within 2 cm of the gastrointestinal tract. From March 2011 to December 2015 at our institution, 40 patients were evaluated (median age, 72 years; range, 38-87 years). All patients underwent PBT at a dose of 60 to 80 cobalt gray equivalents (CGE) in 20 to 38 fractions. The median follow-up period was 19.9 months (range, 1.2-72.3 months). The median tumor size was 36.5 mm (range, 11-124 mm). Kaplan-Meier estimates of the 2-year overall survival, progression-free survival, and local tumor control rates were 76%, 60%, and 94%, respectively. One patient (2.5%) developed a grade 3 gastric ulcer and one (2.5%) developed grade 3 ascites retention; none of the remaining patients developed grade >3 toxicities (National Cancer Institute Common Terminology Criteria for Adverse Events ver. 4.0.). This study indicates that PBT without fiducial markers achieves good local control without severe treatment-related toxicity of the gastrointestinal tract for HCC located within 2 cm of the gastrointestinal tract.

Mathematical Modelling for Patient Selection in Proton Therapy

Proton beam therapy (PBT) is still relatively new in cancer treatment and the clinical evidence base is relatively sparse. Mathematical modelling offers assistance when selecting patients for PBT and predicting the demand for service. Discrete event simulation, normal tissue complication probability, quality-adjusted life-years and Markov Chain models are all mathematical and statistical modelling techniques currently used but none is dominant. As new evidence and outcome data become available from PBT, comprehensive models will emerge that are less dependent on the specific technologies of radiotherapy planning and delivery.

Strategic application of radiotherapy for hepatocellular carcinoma

With increasing clinical use, radiotherapy (RT) has been considered reliable and effective method for hepatocellular carcinoma (HCC) treatment, depending on extent of disease and patient characteristics. RT for HCC can improve therapeutic outcomes through excellent local control, downstaging, conversion from unresectable to resectable status, and treatments of unresectable HCCs with vessel invasion or multiple intrahepatic metastases. In addition, further development of modern RT technologies, including image-guided radiotherapy (IGRT), intensity-modulated radiotherapy (IMRT), and stereotactic body radiotherapy, has expanded the indication of RT. An essential feature of IGRT is that it allows image guidance therapy through in-room images obtained during radiation delivery. Compared with 3D-conformal RT, distinctions of IMRT are inverse treatment planning process and use of a large number of treatment fields or subfields, which provide high precision and exquisitely conformal dose distribution. These modern RT techniques allow more precise treatment by reducing inter- and intra-fractional errors resulting from daily changes and irradiated dose at surrounding normal tissues. More recently, particle therapy has been actively investigated to improve effectiveness of RT. This review discusses modern RT strategies for HCC, as well as optimal selection of RT in multimodal approach for HCC.

Proton beam therapy for hepatocellular carcinoma

INTRODUCTION

Radiation therapy is an effective treatment option for hepatocellular carcinoma (HCC) patients. However, radiotherapy for HCC still has limited recognition as a standard treatment option in international consensus guidelines due to a paucity of randomized controlled trials and the risk of hepatotoxicity, which is primarily mediated by baseline liver function and dose delivered to non-tumor liver cells. Proton beam therapy (PBT) may offer advantages over photon-based radiation treatments through its dosimetric characteristic of sparing more liver volume at low to moderate doses. PBT has the potential to reduce radiation-related hepatotoxicity and allow for tumor dose escalation. Areas covered: This article reviews the clinical rationale for using PBT for HCC patients and clinical outcome and toxicity data from retrospective and prospective studies. PBT-specific technical challenges for these tumors and appropriate selection of patients to be treated with PBT are discussed. Expert commentary: Local control, overall survival, and toxicity results are promising for liver PBT. Future studies, including ongoing randomized cooperative group trials, will aim to determine the incremental benefit of PBT over photons and which patients are most suitable for PBT.

Effects of proton beam irradiation on mitochondrial biogenesis in a human colorectal adenocarcinoma cell line

Proton beam therapy has recently been used to improve local control of tumor growth and reduce side-effects by decreasing the global dose to normal tissue. However, the regulatory mechanisms underlying the physiological role of proton beam radiation are not well understood, and many studies are still being conducted regarding these mechanisms. To determine the effects of proton beams on mitochondrial biogenesis, we investigated: mitochondrial DNA (mtDNA) mass; the gene expression of mitochondrial transcription factors, functional regulators, and dynamic-related regulators; and the phosphorylation of the signaling molecules that participate in mitochondrial biogenesis. Both the mtDNA/nuclear DNA (nDNA) ratio and the mitochondria staining assays showed that proton beam irradiation increases mitochondrial biogenesis in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced aggressive HT-29 cells. Simultaneously, proton beam irradiation increases the gene expression of the mitochondrial transcription factors PGC-1α, NRF1, ERRα, and mtTFA, the dynamic regulators DRP1, OPA1, TIMM44, and TOM40, and the functional regulators CytC, ATP5B and CPT1-α. Furthermore, proton beam irradiation increases the phosphorylation of AMPK, an important molecule involved in mitochondrial biogenesis that is an energy sensor and is regulated by the AMP/ATP ratio. Based on these findings, we suggest that proton beam irradiation inhibits metastatic potential by increasing mitochondrial biogenesis and function in TPA-induced aggressive HT-29 cells.

Long-term outcomes of proton beam therapy in patients with previously untreated hepatocellular carcinoma

Long-term efficacy of proton beam therapy (PBT) remains unclear for patients with previously untreated hepatocellular carcinoma (HCC). We aimed to study the long-term outcomes of PBT according to Barcelona Clinic Liver Cancer (BCLC) staging classifications in patients with previously untreated HCC. The major eligibility criteria of this observational study were an Eastern Cooperative Oncology Group performance status (PS) 0-2, Child-Pugh grade A or B, previously untreated HCC covered within an irradiation field, and no massive ascites. A total of 66.0-77.0 GyE was administered in 10-35 fractions. Local tumor control (LTC), defined as no progression in the irradiated field, progression-free survival (PFS), and overall survival (OS) were assessed according to BCLC staging. From 2002 to 2009 at our institution, 129 patients were eligible. The 5-year LTC, PFS, and OS rates were 94%, 28%, and 69% for patients with 0/A stage disease (n = 9/21), 87%, 23%, and 66% for patients with B stage disease (n = 34), and 75%, 9%, and 25% for patients with C stage disease (n = 65), respectively. The 5-year LTC and OS rates of 15 patients with tumor thrombi in major vessels were 90% and 34%, respectively. Multivariate analyses revealed that PS (0 versus 1-2) was a significant prognostic factor for OS. No grade 3 or higher adverse effects were observed. PBT showed favorable long-term efficacies with mild adverse effects in BCLC stage 0 to C, and can be an alternative treatment for localized HCC especially when accompanied with tumor thrombi. This study was registered with UMIN Clinical Trials Registry (UMIN000025342).