Proton beam radiotherapy versus transarterial chemoembolization for hepatocellular carcinoma: Results of a randomized clinical trial

Comparison of carbon ion radiotherapy and transarterial chemoembolization for unresectable solitary hepatocellular carcinoma >3 cm: a propensity score-matched analysis

This study aimed to compare outcomes between carbon ion radiotherapy (C-ion RT) and transarterial chemoembolization (TACE) in patients with unresectable solitary hepatocellular carcinoma (HCC) >3 cm. Fifty-eight patients who had been treated with C-ion RT (C-ion RT group) and 34 treated with TACE (TACE group) were retrospectively enrolled between January 2016 and December 2021. Propensity score matching was conducted to account for differences between the two groups. The median follow-up duration was 42.1 months for all patients. Propensity score matching successfully balanced the two groups with 29 patients matched to each group. The 3-year overall survival (OS), progression-free survival (PFS) and local control (LC) rates in the C-ion RT vs TACE groups were 75.9% vs 45.4%, 44.8% vs 16.1% and 85.2% vs 23.2%, respectively. The C-ion RT group showed better OS (hazard ratio [HR], 0.578 [95% confidence interval (CI): 0.295-1.132]; P = 0.106), PFS (HR, 0.460 [95% CI: 0.254-0.835]; P = 0.009) and LC (HR, 0.155 [95% CI: 0.062-0.390]; P < 0.001) than the TACE group. Multivariate analysis indicated that C-ion RT was significantly associated with increased PFS (HR, 0.562 [95% CI: 0.341-0.926]; P = 0.024) and LC (HR, 0.282 [95% CI: 0.150-0.528]; P < 0.001). C-ion RT provided better OS, PFS and LC than TACE in patients with solitary HCC >3 cm. This study indicated that C-ion RT is a possible alternative to TACE, which is the standard of care for patients with medium-to-large-sized HCCs.

Emerging evidence-based role for external-beam radiation therapy in hepatocellular carcinoma

The primary curative therapies for hepatocellular carcinoma are resection or liver transplantation. For patients requiring downstaging or who are unresectable at presentation, the landscape of local treatment options has vastly changed over the past decades. This change is partly due to the paucity of high-level evidence to guide the selection of liver-directed therapies, where physician preference and treatment patterns have historically resulted in relegating external-beam radiation therapy (EBRT) to a secondary option in the treatment of hepatocellular carcinoma in cases where arterially directed therapies or thermal ablations were not possible. However, technology advancements have substantially improved the ability to treat liver malignancies with high doses of radiation therapy and to minimise doses to uninvolved hepatic parenchyma and other nearby organs. These advancements have enabled safe treatment of hepatocellular carcinoma with EBRT, with low risk of toxicity. Recent randomised trials support the role of EBRT in the treatment of hepatocellular carcinoma from early to advanced stages. These trials identified that EBRT improved several key patient-centred outcomes, including overall survival when using stereotactic body radiotherapy and sorafenib compared with sorafenib alone in unresectable hepatocellular carcinoma, recurrence-free survival with the use of adjuvant EBRT in select patients after hepatocellular carcinoma resection, and quality of life for patients with painful hepatocellular carcinoma masses treated with palliative EBRT. With emerging high-quality evidence, hepatocellular carcinoma therapeutic guidelines should include the growing role of EBRT in improving the quality and quantity of life for patients with liver cancer.

Proton beam therapy in the management of hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer. Photon radiotherapy shows efficacy in treating HCC but carries risks of high exit dose and radiation-induced liver disease. Additionally, HCCs with portal vein tumor thrombosis (PVTT) have a poor prognosis and are associated with higher risk of death. In recent years, proton beam therapy (PBT) has emerged as a novel treatment with the ability to downstage HCC for liver transplant (LT).

AREAS COVERED

This review will provide an overview of dosimetric benefits of PBT, efficacy of PBT in treating HCC, downstaging HCC-PVTT for LT, and a comparison of PBT with other non-surgical techniques. A search of PubMed until 3 September 2024 was conducted using free search and the following keywords: hepatocellular carcinoma, proton beam therapy, portal vein tumor thrombosis, local ablative therapy, trans-arterial chemoembolization, stereotactic body radiotherapy, Y-90 radioembolization.

EXPERT OPINION

Various clinical trials using PBT have shown promising tumor local control and overall survival rates. PBT is mostly safe and efficacious for downstaging HCC-PVTT for LT. PBT has also been shown to be non-inferior to various other treatment modalities. Future research should focus on combinations of PBT with other modalities.

Advances in radiation therapy for HCC: Integration with liver-directed treatments

HCC is the fourth leading cause of cancer-related mortality with increasing incidence worldwide. Historically, treatment for early disease includes liver transplantation, surgical resection, and/or other local therapies, such as thermal ablation. As a result of technical advances and high-quality prospective data, the use of definitive external beam radiotherapy with ablative doses has emerged. Intermediate-stage disease has been generally addressed with arterially directed therapies (eg, chemoembolization or radioembolization) and external beam radiotherapy, while advanced stages have been addressed by systemic therapy or best supportive care. The role of each local/locoregional therapy has rapidly evolved in the context of novel pharmacotherapies, including immunotherapies and antiangiogenic agents. The combinations, indications, and timing of treatments vary widely among specialties and geographies. Here, we aim to synthesize the best quality evidence available regarding the efficacy and safety of different liver-directed modalities, with a focus on recent prospective clinical data of external beam radiotherapy within the context of other available liver-directed therapies across Barcelona Liver Classification (BCLC) stages.

Gastrointestinal side effects in hepatocellular carcinoma patients receiving transarterial chemoembolization: a meta-analysis of 81 studies and 9495 patients

Background

Transarterial chemoembolization (TACE) is a widely used treatment for hepatocellular carcinoma (HCC), combining targeted chemotherapy and embolization. While effective, TACE can be associated with significant gastrointestinal (GI) side effects, impacting a patient's quality of life.

Objectives

Quantify the prevalence of key GI complications (diarrhea, nausea, GI toxicity, abdominal pain) following TACE.

Design

Systematic review was performed following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, focusing on studies that reported side effects of TACE. Studies not involving cTACE or drug-eluting bead TACE (DEB-TACE), non-HCC studies, meta-analyses or systematic reviews, and inaccessible publications were excluded.

Data sources and methods

A PubMed search for clinical and randomized trials was conducted. Extracted data included study identifiers, demographics, TACE details, and GI side effect prevalences. The Mixed Methods Appraisal Tool assessed study quality and bias.

Results

The analysis included data from 81 studies with 121 individual study arms and 9495 patients. Diarrhea was reported in 38 studies, with a mean prevalence of 23.46% (2.5; 95% confidence interval (CI): 18.39-28.544) and a weighted prevalence of 23.5%. Nausea was most frequently reported, mentioned in 67 studies, with a mean prevalence of 34.66% (2.4; 95% CI: 29.89-39.44) and a weighted prevalence of 32.5%. Abdominal pain was reported in 59 studies, with the highest mean prevalence of 48.07% (2.9; 95% CI: 42.20-53.93) and a weighted prevalence of 46.1%. GI toxicity was reported in 32 studies, with a mean prevalence of 8.85% (1.4; 95% CI: 5.99-11.70) and a weighted prevalence of 9.9%. DEB-TACE generally led to slightly higher rates of nausea, diarrhea, abdominal pain, and GI toxicity compared to conventional TACE. The type of chemotherapy agent influenced prevalence of GI-side effects, with high prevalences observed for agents such as zinostatin and cisplatin.

Conclusion

This meta-analysis synthesizes current evidence on managing GI side effects in TACE. Standardizing reporting and developing effective management strategies are crucial to improving patient outcomes.

Meta-analysis of randomized controlled trials of external-beam radiation versus transarterial chemoembolization for hepatocellular carcinoma

BACKGROUND

External-beam radiation (EBRT) is a noninvasive therapeutic alternative to transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). The objective of this study was to conduct a systematic review and meta-analysis of prospective randomized clinical trials to assess the clinical efficacy of EBRT versus TACE for HCC as either a definitive monotherapy or as a bridge to transplantation/surgery.

METHODS

A systematic review and meta-analysis were performed to include prospective randomized trials comparing EBRT versus TACE. Data was analyzed with random and fixed-effects models. The inconsistency index (I2) was chosen to assess heterogeneity. Three publications were included with a total of 142 patients. Outcomes included local control (LC), overall survival (OS), progression-free survival (PFS), and occurrences of grade ≥3 toxicity. Comparisons are reported as hazard ratios (HRs) or risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

There were three randomized trials that met inclusion criteria. The EBRT was delivered in three to 15 fractions with a total dose between 30 and 75 gray(Gy). EBRT was associated with significantly improved LC (HR, 0.16; 95% CI, 0.08-0.34; I2 = 0%) and PFS (HR, 0.37; 95% CI, 0.23-0.60; I2, 0%) compared with TACE. There was no significant difference between EBRT and TACE in OS (RR, 0.79; 95% CI, 0.51-1.22; I2 = 0%) or grade ≥3 toxicity (RR, 0.86; 95% CI, 0.31-2.37; I2 = 57%). None of the analyses had statistically significant heterogeneity.

CONCLUSIONS

Compared with TACE, EBRT yields superior LC and PFS without providing a survival benefit in early and intermediate stage HCC. Additional larger prospective randomized controlled trials should be conducted to further investigate differences in clinical outcomes amongst patients with more advanced disease.

External Beam Radiation therapy After Transarterial Chemoembolization Versus Transarterial Chemoembolization Alone for Treatment of Inoperable Hepatocellular Carcinoma: A Randomized Phase 3 Trial

PURPOSE

To compare the outcomes of transarterial chemoembolization (TACE) alone with those of TACE combined with external beam radiation therapy (EBRT) in patients with hepatocellular carcinoma (HCC) in a multicenter randomized study.

METHODS AND MATERIALS

From 2017 to 2022, 74 HCC patients with tumors confined to the liver without vascular invasion were treated with either TACE only (TACE group, 39 patients) or TACE combined with EBRT (TACE + EBRT group, 35 patients). The primary outcome measured was overall survival (OS). Secondary outcomes included progression-free survival (PFS), local tumor control, and the assessment of treatment-related toxicity.

RESULTS

Due to slow accrual, the trial was closed prematurely after enrolling 74 patients. All patients received 2 cycles of TACE before randomization. The TACE and TACE + EBRT groups showed comparable patient and tumor characteristics. The TACE group underwent a median of 3 TACE cycles, and the TACE + EBRT group received 2 cycles of TACE, and a median of 5500 cGy in 15 fractions. For the TACE group, the median local control (LC) duration was 13.1 months, whereas for the TACE + EBRT group, the median LC was not achieved (P < .001). The PFS was recorded at 11.6 months in the TACE group compared with 15.4 months in the TACE + EBRT group (P = .072). The median OS reached 36.8 months for the TACE group and extended to 47.1 months for the TACE + EBRT group (P = .654). The incidence of toxicity was comparable between both groups.

CONCLUSIONS

Although the number of patients enrolled in this clinical trial did not meet expectations. TACE combined with EBRT was shown to be more effective than TACE alone in improving LC without increasing toxicity, whereas PFS and OS were slightly improved. TACE + EBRT can be used as a standard treatment option for patients with inoperable but confined intrahepatic HCC.

EASL Clinical Practice Guidelines on the management of hepatocellular carcinoma

Liver cancer is the third leading cause of cancer-related deaths worldwide, with hepatocellular carcinoma (HCC) accounting for approximately 90% of primary liver cancers. Advances in diagnostic and therapeutic tools, along with improved understanding of their application, are transforming patient treatment. Integrating these innovations into clinical practice presents challenges and necessitates guidance. These clinical practice guidelines offer updated advice for managing patients with HCC and provide a comprehensive review of pertinent data. Key updates from the 2018 EASL guidelines include personalised surveillance based on individual risk assessment and the use of new tools, standardisation of liver imaging procedures and diagnostic criteria, use of minimally invasive surgery in complex cases together with updates on the integrated role of liver transplantation, transitions between surgical, locoregional, and systemic therapies, the role of radiation therapies, and the use of combination immunotherapies at various stages of disease. Above all, there is an absolute need for a multiparametric assessment of individual risks and benefits, considering the patient's perspective, by a multidisciplinary team encompassing various specialties.

Exploring the Evolving Landscape of Stereotactic Body Radiation Therapy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) carries significant morbidity and mortality. Management of the HCC requires a multidisciplinary approach. Surgical resection and liver transplantation are the gold standard options for the appropriate settings. Stereotactic body radiation therapy (SBRT) has emerged as a promising treatment modality in managing HCC; its use is more studied and well-established in advanced HCC (aHCC). Current clinical guidelines universally endorse SBRT as a viable alternative to radiofrequency ablation (RFA), transarterial chemoembolisation (TACE), and transarterial radioembolisation (TARE), a recommendation substantiated by literature demonstrating comparable efficacy among these modalities. In early-stage HCC, SBRT primarily manages unresectable tumours unsuitable for ablative procedures such as microwave ablation and RFA. SBRT has been incorporated as a modality to downstage tumours or as a bridge to transplant. In the case of intermediate or advanced HCC, SBRT offers excellent results either as a single modality or adjunct to other locoregional modalities such as TACE/TARE. Recent data from late-stage HCC patients illustrate the effectiveness of SBRT in achieving local tumour control while minimising damage to surrounding healthy liver tissue. It has promising local control of approximately 80-90% in managing HCC. Additional prospective data comparing the efficacy of SBRT with the first-line recommended therapies such as RFA, TACE, and surgery are essential. The standard of care for patients with advanced/metastatic disease is systemic therapy (immunotherapy/tyrosine kinase inhibitors). SBRT, in combination with immune-checkpoint inhibitors, has an immune-modulatory effect that results in a synergistic effect. Recent findings indicate that the combination of immunotherapy and SBRT in HCC is well-tolerated and exhibits synergistic effects. Further exploration of diverse immunotherapy and radiotherapy strategies is essential to identify the appropriate time for combination treatments and to optimise dose and fraction regimens. Prospective, randomised studies are imperative to establish SBRT as the primary treatment for HCC.

Locoregional Therapies for Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Importance

Several locoregional therapies (LRTs) for nonmetastatic hepatocellular carcinoma (HCC) are available; however, a global comparison of the relative efficacy of each is needed.

Objective

To conduct a systematic review and direct, pairwise meta-analytic comparison of all identified randomized clinical trials evaluating the treatment of nonmetastatic HCC.

Data Sources

A comprehensive search of PubMed and the proceedings of the American Society of Clinical Oncology and American Society for Radiation Oncology annual meetings from January 1, 2010, to November 1, 2023, was performed.

Study Selection

Randomized clinical trials using a form of LRT (surgery with or without adjuvant therapy, radiofrequency ablation [RFA], microwave ablation [MWA], radiotherapy [RT], hepatic arterial infusion chemotherapy [HAIC], transarterial bland embolization [TAE], transarterial chemoembolization [TACE], or transarterial radioembolization [TARE]).

Data Extraction and Synthesis

Study eligibility and data extraction were each reviewed by 2 authors independently. Random-effects meta-analyses were used to compare treatment categories.

Main Outcomes and Measures

Progression-free survival (PFS) was the primary outcome; overall survival (OS) was the secondary outcome.

Results

Forty randomized clinical trials reporting on comparative outcomes of 11 576 total patients with localized HCC treated with LRT were included. The median follow-up was 30.0 (IQR, 18.5-40.8) months. Direct pooled comparisons between treatment classes suggested improved outcomes for surgery combined with adjuvant therapy over surgery alone (PFS: hazard ratio [HR], 0.62 [95% CI, 0.51-0.75]; P < .001; OS: HR, 0.61 [95% CI, 0.48-0.78]; P < .001), surgery over RFA (PFS: HR, 0.74 [95% CI, 0.63-0.87]; P < .001; OS: HR, 0.71 [95% CI, 0.54-0.95]; P = .02), RT over TACE (PFS: HR, 0.35 [95% CI, 0.21-0.60]; P < .001; OS: HR, 0.35 [95% CI, 0.13-0.97]; P = .04), and HAIC over TACE (PFS: HR, 0.57 [95% CI, 0.45-0.72]; P < .001; OS: HR, 0.58 [95% CI, 0.45-0.75]; P < .001). No substantial heterogeneity was noted for any pairwise comparison with the exception of RT-based regimens compared with tyrosine kinase inhibitor therapy.

Conclusions and Relevance

The findings of this systematic review and direct, pairwise meta-analysis suggest that all LRTs are not equivalent for the treatment of localized HCC. The efficacy of LRTs appears hierarchical, with surgery-based management outcomes associated with the best treatment outcomes and embolization-based treatment options associated with the worst treatment outcomes.

A Review of Stereotactic Body Radiotherapy in the Management of Gastrointestinal Malignancies

ABSTRACT

In this review, we explore the role of stereotactic body radiotherapy (SBRT) and other advanced radiotherapy techniques in the treatment of gastrointestinal malignancies, which primarily involves primary and secondary liver cancers and pancreatic cancers. The review examines radiotherapy in both curative and palliative settings, emphasizing the evolution of SBRT and hypofractionation as alternatives to conventional radiotherapy. We review the recent literature evaluating radiotherapy in the management of unresectable, borderline resectable, and metastatic pancreatic cancer, highlighting recent advances in radiotherapy techniques that aim to improve local control, reduce toxicity, and increase resectability in appropriate patients. For primary liver cancers (hepatocellular carcinoma and cholangiocarcinoma), SBRT has emerged as a potential noninvasive alternative to surgery, particularly in patients with unresectable tumors or those awaiting liver transplantation. The review also provides insights into ongoing clinical trials, comparative studies between SBRT and other local therapies such as radiofrequency ablation, and the use of radiotherapy in managing liver metastases from various primary cancers. Throughout, we emphasize limitations in the available literature and highlight areas of ongoing and future investigation.

Proton Radiation Therapy: A Systematic Review of Treatment-Related Side Effects and Toxicities

Cancer is the second leading cause of death worldwide. Around half of all cancer patients undergo some type of radiation therapy throughout the course of their treatment. Photon radiation remains (RT) the most widely utilized modality of radiotherapy despite recent advancements in proton radiation therapy (PBT). PBT makes use of the particle's biological property known as the Bragg peak to better spare healthy tissue from radiation damage, with data to support that this treatment modality is less toxic than photon RT. Hence, proton radiation dosimetry looks better compared to photon dosimetry; however, due to proton-specific uncertainties, unexpected acute, subacute, and long-term toxicities can be encountered. Reported neurotoxicity resulting from proton radiation treatments include radiation necrosis, moyamoya syndrome, neurosensory toxicities, brain edema, neuromuscular toxicities, and neurocognitive toxicities. Pulmonary toxicities include pneumonitis and fibrosis, pleural effusions, and bronchial toxicities. Pericarditis, pericardial effusions, and atrial fibrillations are among the cardiac toxicities related to proton therapy. Gastrointestinal and hematological toxicities are also found in the literature. Genitourinary toxicities include urinary and reproductive-related toxicities. Osteological, oral, endocrine, and skin toxicities have also been reported. The side effects will be comparable to the ones following photon RT, nonetheless at an expected lower incidence. The toxicities collected mainly from case reports and clinical trials are described based on the organs affected and functions altered.

Recent update of proton beam therapy for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUNDS/AIMS

Although access to proton beam therapy (PBT) is limited worldwide, its use for the treatment of hepatocellular carcinoma (HCC) is gradually increasing with the expansion of new facilities. Therefore, we conducted a systematic review and metaanalysis to investigate the updated evidence of PBT for HCC.

METHODS

The MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were systematically searched for studies that enrolled patients with liver-confined HCC that were treated with PBT for a cure up to February 2024.

RESULTS

A total of 1,858 HCC patients receiving PBT from 22 studies between 2004 and 2023 were selected for this meta-analysis. The median proportion of Child-Pugh class A was 86% (range, 41-100), and the median tumor size was 3.6 cm (range, 1.2-9.0). The median total dose ranged from 55 GyE to 76 GyE (median, 69). The pooled rates of 3- and 5-year local progression-free survival after PBT were 88% (95% confidence interval [CI], 85-91) and 86% (95% CI, 82-90), respectively. The pooled 3- and 5-year overall rates were 60% (95% CI, 54-66) and 46% (95% CI, 38-54), respectively. The pooled rates of grade 3 hepatic toxicity, classic radiationinduced liver disease (RILD), and non-classic RILD were 1%, 2%, and 1%, respectively.

CONCLUSIONS

The current study supports PBT for HCC and demonstrates favorable long-term survival and low hepatic toxicities compared with other published studies on other radiotherapy modalities. However, further studies are needed to identify the subgroups that will benefit from PBT.

Initial Trans-Arterial Chemo-Embolisation (TACE) Is Associated with Similar Survival Outcomes as Compared to Upfront Percutaneous Ablation Allowing for Follow-Up Treatment in Those with Single Hepatocellular Carcinoma (HCC) ≤ 3 cm: Results of a Real-World Propensity-Matched Multi-Centre Australian Cohort Study

Percutaneous ablation is recommended in Barcelona Clinic Liver Cancer (BCLC) stage 0/A patients with HCC ≤3 cm as a curative treatment modality alongside surgical resection and liver transplantation. However, trans-arterial chemo-embolisation (TACE) is commonly used in the real-world as an initial treatment in patients with single small HCC in contrast to widely accepted clinical practice guidelines which typically describe TACE as a treatment for intermediate-stage HCC. We performed this real-world propensity-matched multi-centre cohort study in patients with single HCC ≤ 3 cm to assess for differences in survival outcomes between those undergoing initial TACE and those receiving upfront ablation. Patients with a new diagnosis of BCLC 0/A HCC with a single tumour ≤3 cm first diagnosed between 1 January 2016 and 31 December 2020 who received initial TACE or ablation were included in the study. A total of 348 patients were included in the study, with 147 patients receiving initial TACE and 201 patients undergoing upfront ablation. After propensity score matching using key covariates, 230 patients were available for analysis with 115 in each group. There were no significant differences in overall survival (log-rank test p = 0.652) or liver-related survival (log-rank test p = 0.495) over a median follow-up of 43 months. While rates of CR were superior after ablation compared to TACE as a first treatment (74% vs. 56%, p < 0.004), there was no significant difference in CR rates when allowing for further subsequent treatments (86% vs. 80% p = 0.219). In those who achieved CR, recurrence-free survival and local recurrence-free survival were similar (log rank test p = 0.355 and p = 0.390, respectively). Our study provides valuable real-world evidence that TACE when offered with appropriate follow-up treatment is a reasonable initial management strategy in very early/early-stage HCC, with similar survival outcomes as compared to those managed with upfront ablation. Further work is needed to better define the role for TACE in BCLC 0/A HCC.

Expanding Indications for Liver Transplantation in the Treatment of Hepatocellular Carcinoma

Improvements in downstaging therapies have expanded the indications for liver transplantation (LT) for hepatocellular carcinoma (HCC). Patients with more advanced disease are now considered candidates due to advancements in radiation therapy, combination therapies, and immunotherapy. Combination stereotactic body radiation therapy (SBRT) and trans-arterial chemoembolization (TACE) has been shown to be superior to the historic treatment, sorafenib, in patients with macrovascular invasion. These patients are now candidates for LT with stable disease after LRT. Patients with ruptured HCC and prolonged stability have also been shown to have acceptable outcomes. The role of neoadjuvant immunotherapy needs to be further defined and has the potential to further improve tumor control prior to transplant.

Temporal Evolution and Diagnostic Diversification of Patients Receiving Proton Therapy in the United States: A Ten-Year Trend Analysis (2012 to 2021) From the National Association for Proton Therapy

PURPOSE

The National Association for Proton Therapy conducted 8 surveys of all operational United States proton centers (2012-2021) and analyzed the patients treated, diagnoses, and treatment complexity to evaluate trends and diversification of patients receiving proton therapy.

METHODS AND MATERIALS

Detailed surveys were sent in 2015, which requested data from 2012 to 2014, and then annually thereafter to active proton centers in the United States. The numbers of patient treated at each center for the preceding calendar year(s) were collated for tumors in the following categories: central nervous system, intraocular, pituitary, skull base/skeleton, head/neck, lung, retroperitoneal/soft tissue sarcoma, pediatric (solid tumors in children of age ≤18), gastrointestinal tract, urinary tract, female pelvic, prostate, breast, and "other." Complexity levels were assessed using Current Procedural Terminology codes 77520-77525.

RESULTS

Survey response rates were excellent (100% in 2015 to 94.9% in 2021); additional publicly available information provided near-complete information on all centers. Trend comparisons between 2012 and 2021 showed that the total annual number of patients treated with protons gradually increased from 5377 to 15,829. The largest numeric increases were for head/neck (316 to 2303; 7.3-fold), breast (93 to 1452; 15.6-fold), and gastrointestinal tumors (170 to 1259; 7.4-fold). Patient numbers also increased significantly for central nervous system (598 to 1743; 2.9-fold), pediatric (685 to 1870; 2.7-fold), and skull base tumors (179 to 514; 2.9-fold). For prostate cancer, the percentage of proton-treated patients decreased from 43.4% to 25.0% of the total. Simple compensated treatments decreased from 43% in 2012 to 7% in 2021, whereas intermediate complexity treatments increased from 45% to 73%.

CONCLUSIONS

The number of patients treated with protons is gradually increasing, with a substantial proportionate decline in patients with prostate cancer receiving proton therapy. The number of patients treated for "commonly accepted" indications for protons (eg, pediatric, central nervous system, and skull base tumors) is gradually increasing. Greater proportional increases were observed for breast, lung, head/neck, and gastrointestinal tumors. Treatment complexity is gradually increasing over time.

Carbon ion radiotherapy of hepatocellular carcinoma provides excellent local control: The prospective phase I PROMETHEUS trial

Background & Aims

Inoperable hepatocellular carcinoma (HCC) can be treated by stereotactic body radiotherapy. However, carbon ion radiotherapy (CIRT) is more effective for sparing non-tumorous liver. High linear energy transfer could promote therapy efficacy. Japanese and Chinese studies on hypofractionated CIRT have yielded excellent results. Because of different radiobiological models and the different etiological spectrum of HCC, applicability of these results to European cohorts and centers remains questionable. The aim of this prospective study was to assess safety and efficacy and to determine the optimal dose of CIRT with active raster scanning based on the local effect model (LEM) I.

Methods

CIRT was performed every other day in four fractions with relative biological effectiveness (RBE)-weighted fraction doses of 8.1-10.5 Gy (total doses 32.4-42.0 Gy [RBE]). Dose escalation was performed in five dose levels with at least three patients each. The primary endpoint was acute toxicity after 4 weeks.

Results

Twenty patients received CIRT (median age 74.7 years, n = 16 with liver cirrhosis, Child-Pugh scores [CP] A5 [n = 10], A6 [n = 4], B8 [n = 1], and B9 [n = 1]). Median follow up was 23 months. No dose-limiting toxicities and no toxicities exceeding grade II occurred, except one grade III gamma-glutamyltransferase elevation 12 months after CIRT, synchronous to out-of-field hepatic progression. During 12 months after CIRT, no CP elevation occurred. The highest dose level could be applied safely. No local recurrence developed during follow up. The objective response rate was 80%. Median overall survival was 30.8 months (1/2/3 years: 75%/64%/22%). Median progression-free survival was 20.9 months (1/2/3 years: 59%/43%/43%). Intrahepatic progression outside of the CIRT target volume was the most frequent pattern of progression.

Conclusions

CIRT of HCC yields excellent local control without dose-limiting toxicity.

Impact and implications

To date, safety and efficacy of carbon ion radiotherapy for hepatocellular carcinoma have only been evaluated prospectively in Japanese and Chinese studies. The optimal dose and fractionation when using the local effect model for radiotherapy planning are unknown. The results are of particular interest for European and American particle therapy centers, but also of relevance for all specialists involved in the treatment and care of patients with hepatocellular carcinoma, as we present the first prospective data on carbon ion radiotherapy in hepatocellular carcinoma outside of Asia. The excellent local control should encourage further use of carbon ion radiotherapy for hepatocellular carcinoma and design of randomized controlled trials.

Clinical Trials Registration

The study is registered at ClinicalTrials.gov (NCT01167374).

Do We Have a Winner? Advocating for SBRT in HCC Management

•Stereotactic body radiotherapy (SBRT) is a safe and effective locoregional therapy for inoperable patients with HCC.•SBRT compares favorably with other local therapies in terms of local control, survival, morbidity, and cost-effectiveness.•SBRT should be considered and discussed in multidisciplinary management of appropriate HCC patients.•Advances in SBRT and novel combinations with systemic therapy may further widen the therapeutic index in HCC.

Proton Beam Therapy for Hepatocellular Carcinoma: Multicenter Prospective Registry Study in Japan

PURPOSE

A prospective multicenter registry study was started May 2016 in Japan to evaluate the efficacy and safety of proton beam therapy (PBT) for hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

Patients who received PBT for HCC from May 2016 to June 2018 were registered in the database of the Particle Beam Therapy Committee and Subcommittee of the Japanese Society for Radiation Oncology. Overall survival (OS), progression-free survival (PFS), and local recurrence were evaluated.

RESULTS

Of the 755 registered patients, 576 with initial PBT and no duplicate cancer were evaluated. At final follow-up, 322 patients were alive and 254 had died. The median follow-up period for survivors was 39 months (0-58 months). The median OS time of the 576 patients was 48.8 months (95% CI, 42.0-55.6 months) and the 1-, 2-, 3-, and 4-year OS rates were 83.8% (95% CI, 80.5%-86.6%), 68.5% (64.5%-72.2%), 58.2% (53.9%-62.2%), and 50.1% (44.9%-55.0%), respectively. Recurrence was observed in 332 patients, including local recurrence in 45 patients. The median PFS time was 14.7 months (95% CI, 12.4-17.0 months) and the 1-, 2-, 3-, and 4-year PFS rates were 55.2% (95% CI, 51.0%-59.2%), 37.5% (33.5%-41.5%), 30.2% (26.3%-34.2%), and 22.8% (18.5%-27.4%), respectively. The 1-, 2-, 3-, and 4-year OS rates were significantly higher for tumor size <5 versus 5 to 10 cm (P < .001) and <5 versus ≥10 cm (P < .001); Child-Pugh score A/B versus C (P < .001); and distance of the tumor from the gastrointestinal tract <1 versus 1 to 2 cm (P < .008) and <1 versus >2 cm (P < .001). At final follow-up, 27 patients (4.7%) had late adverse events of grade 3 or higher, with liver failure (n = 7), and dermatitis (n = 7) being most common.

CONCLUSIONS

This multicenter prospective data registry indicated that PBT for HCC gives good therapeutic effects (3-year local control rate of 90%) with a low risk of severe late adverse events.

SBRT for Liver Tumors: What the Interventional Radiologist Needs to Know

This review summarizes the clinical evidence supporting the utilization of stereotactic body radiotherapy (SBRT) for liver tumors, including hepatocellular carcinoma, liver metastases, and cholangiocarcinoma. Emerging prospective evidence has demonstrated the benefit and low rates of toxicity across a broad range of clinical contexts. We provide an introduction for the interventional radiologist, with a discussion of underlying themes such as tumor dose-response, mitigation of liver toxicity, and the technical considerations relevant to performing liver SBRT. Ultimately, we recommend that SBRT should be routinely included in the armamentarium of locoregional therapies for liver malignancies, alongside those liver-directed therapies offered by interventional radiology.

Tumor Response on Diagnostic Imaging after Proton Beam Therapy for Hepatocellular Carcinoma

BACKGROUND

Follow-up after treatment for hepatocellular carcinoma (HCC) can be mostly performed using dynamic CT or MRI, but there is no common evaluation method after radiation therapy. The purpose of this study is to examine factors involved in tumor reduction and local recurrence in patients with HCC treated with proton beam therapy (PBT) and to evaluate HCC shrinkage after PBT.

METHODS

Cases with only one irradiated lesion or those with two lesions irradiated simultaneously were included in this study. Pre- and post-treatment lesions were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST) by measuring the largest diameter.

RESULTS

The 6-, 12-, and 24-month CR + PR rates after PBT were 33.1%, 57.5%, and 76.9%, respectively, and the reduction rates were 25.1% in the first 6 months, 23.3% at 6-12 months, and 14.5% at 13-24 months. Cases that reached CR/PR at 6 and 12 months had improved OS compared to non-CR/non-PR cases.

CONCLUSIONS

It is possible that a lesion that reached SD may subsequently transition to PR; it is reasonable to monitor progress with periodic imaging evaluations even after 1 year of treatment.

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.

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.