High-dose proton beam radiotherapy of hepatocellular carcinoma: preliminary results of a phase II trial

Combination and Optimal Sequencing of Systemic and Locoregional Therapies in Hepatocellular Carcinoma: Proceedings from the Society of Interventional Radiology Foundation Research Consensus Panel

Hepatocellular carcinoma, historically, has had a poor prognosis with very few systemic options. Furthermore, most patients at diagnosis are not surgical candidates. Therefore, locoregional therapy (LRT) has been widely used, with strong data supporting its use. Over the last 15 years, there has been progress in the available systemic agents. This has led to the updated Barcelona Clinic Liver Cancer (BCLC) algorithm's inclusion of these new systemic agents, with advocacy of earlier usage in those who progress on LRT or have tumor characteristics that make them less likely to benefit from LRT. However, neither the adjunct of LRT nor the specific sequencing of combination therapies is addressed directly. This Research Consensus Panel sought to highlight research priorities pertaining to the combination and optimal sequencing of LRT and systemic therapy, assessing the greatest needs across BCLC stages.

Hepatic Resection vs Particle Therapy as an Initial Treatment for Single Hepatocellular Carcinoma: Bi-institutional Propensity Score-Matched Analysis

BACKGROUND

Curative treatment for hepatocellular carcinoma (HCC) is limited to hepatic resection (HR), radiofrequency ablation, and liver transplantation, but the value of particle therapy (PT) as an initial treatment remains unclear. This study aimed to compare the outcomes of HR and PT for single HCC.

STUDY DESIGN

A total of 554 patients with single HCC without vascular invasion were enrolled from January 2000 to December 2015. Patients underwent either HR (n = 279) or PT (n = 275) as initial treatments. A one-to-one propensity score-matching analysis was performed to evaluate the overall survival (OS) and progression-free survival after dividing patients according to liver function as assessed by the modified albumin-bilirubin grade.

RESULTS

The median OS (130 vs 85 months, p = 0.001) and progression-free survival (47 vs 30 months HR, p = 0.004) of HR were also significantly better than that of PT in the propensity score-matching cohort with modified albumin-bilirubin grade 1/2a (n = 145 per group). Meanwhile, in a propensity score-matching cohort with modified albumin-bilirubin grade 2b/3 (n = 53 per group), there were no significant differences in median OS and progression-free survival between HR and PT.

CONCLUSIONS

HR may be preferable as an initial treatment for patients with single HCC without vascular invasion, especially those with preserved liver function. PT can be an acceptable alternative to HR for patients without surgical indication and/or impaired liver function.

Proton Therapy in the Management of Hepatocellular Carcinoma

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.

Hypofractionated proton beam radiotherapy in patients with unresectable liver tumors: multi-institutional prospective results from the Proton Collaborative Group

Background

Recent advances in radiotherapy techniques have allowed ablative doses to be safely delivered to inoperable liver tumors. In this setting, proton beam radiotherapy (PBT) provides the means to escalate radiation dose to the target volume while sparing the uninvolved liver. This study evaluated the safety and efficacy of hypofractionated PBT for liver tumors, predominantly hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC).

Methods

We evaluated the prospective registry of the Proton Collaborative Group for patients undergoing definitive PBT for liver tumors. Demographic, clinicopathologic, toxicity, and dosimetry information were compiled.

Results

To date, 63 patients have been treated at 9 institutions between 2013 and 2019. Thirty (48%) had HCC and 25 (40%) had ICC. The median dose and biological equivalent dose (BED) delivered was 58.05 GyE (range 32.5–75) and 80.5 GyE (range 53.6–100), respectively. The median mean liver BED was 13.9 GyE. Three (4.8%) patients experienced at least one grade ≥ 3 toxicity. With median follow-up of 5.1 months (range 0.1–40.8), the local control (LC) rate at 1 year was 91.2% for HCC and 90.9% for ICC. The 1-year LC was significantly higher (95.7%) for patients receiving BED greater than 75.2 GyE than for patients receiving BED of 75.2 GyE or lower (84.6%, p = 0.029). The overall survival rate at 1 year was 65.6% for HCC and 81.8% for ICC.

Conclusions

Hypofractionated PBT results in excellent LC, sparing of the uninvolved liver, and low toxicity, even in the setting of dose-escalation. Higher dose correlates with improved LC, highlighting the importance of PBT especially in patients with recurrent or bulky disease.

The effectiveness of proton beam therapy for liver metastatic recurrence in gastric cancer patients

OBJECTIVE

The purpose of this cross-sectional study was to evaluate the efficacy and safety of proton beam therapy for liver metastatic recurrence in gastric cancer patients.

METHODS

Consecutive patients who underwent proton beam therapy from 2010 to 2015 were isolated from our institutional database. Patients with extrahepatic metastatic lesions were excluded. Seven patients were enrolled. The median diameter of target lesions was 31 mm (13-68 mm). The most frequent dosage was 72.6 Gy equivalent in 22 fractions. The effectiveness was assessed based on the local control, overall survival and progression-free survival rates. The local control, overall survival and progression-free survival rates were calculated using the Kaplan-Meier method. Adverse events were described according to the patients' medical records.

RESULTS

The median follow-up period was 41.7 months (20.7-66.3 months). The 3-year local control, overall survival and progression-free survival rates were 85.7, 68.6 and 43%, respectively. All patients completed proton beam therapy without interruption. No grade ≥3 adverse events were observed.

CONCLUSIONS

Proton beam therapy might be a treatment option for patients with liver metastasis of gastric cancer.

Clinical results of active scanning proton therapy for primary liver tumors

BACKGROUND

Evidence for the efficacy of radiation therapy for primary liver cancer is growing. In this context, proton therapy (PT) can potentially improve the therapeutic ratio, as demonstrated by recent clinical studies. Here we report the first European clinical experience on the use of PT for primary liver cancer.

METHODS

All patients treated for primary liver cancer in our center entered the analysis. Patients were simulated during deep expiration breath-hold. A 15-fraction treatment schedule was adopted using active scanning PT. Clinical outcome and toxicity were retrospectively analyzed.

RESULTS

Between January 2018 and December 2019, 18 patients were treated. Fourteen patients had hepatocellular carcinoma (HCC), three patients had intrahepatic cholangiocarcinoma (ICC), and one patient had synchronous ICC-HCC. The Child-Pugh score was A5 in the majority of patients with HCC (71.4%). Median prescription dose was 58.05 Gy (range, 50.31-67.5). Median follow-up was 10 months (range, 1-19). The majority of deaths occurred from liver tumor progression. One-year overall survival (OS) was 63%. A significant correlation between worse OS and patient performance status, vascular invasion, and tumor stage was recorded. One-year local control was 90%. Toxicity was low, with a decrease in Child-Pugh score ⩾2 points detected in one patient. No cases of classic radiation-induced liver disease occurred.

CONCLUSIONS

Our initial results of active scanning PT for primary liver cancer demonstrated the feasibility, safety, and effectiveness of this advanced technique in this setting. The potential of the combination of PT with other locoregional therapies is under evaluation.

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.

Proton Beam Therapy in Liver Malignancies

PURPOSE OF REVIEW

Proton beam therapy (PBT) allows for improved sparing of surrounding normal tissues compared with X-ray-based radiation therapy. This is especially important in the setting of liver malignancies, where an increase in integral dose leads to a higher risk of radiation-induced liver disease (RILD) as well as close proximity to vital gastrointestinal (GI) organs.

RECENT FINDINGS

We have data from multiple centers demonstrating that PBT can safely deliver high, ablative doses of radiation therapy conferring excellent local control with good tolerance of treatment. PBT is an effective treatment with longstanding evidence of efficacy that is increasing in availability.

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.

Advancements and challenges in treating advanced gastric cancer in the West

Gastric cancer is a leading cause of cancer incidence and death worldwide. Patients with advanced gastric cancer benefit from a multi-modality treatment regimen. Sound oncologic resection with negative margins and complete lymphadenectomy plays a crucial role in long-term survival for patients with resectable disease. The utilization of minimally invasive techniques for gastric cancer has been slowly increasing and is proving to be both technically and oncologically safe. Perioperative chemotherapy is the current standard of care for advanced gastric cancer. A variety of chemotherapy regimens have been used with the combination of docetaxel, oxaliplatin, 5-fluorouracil, and leucovorin being the current recommendation given its superior ability to induce a complete pathologic response and prolong survival. The use of radiation has been more controversial with its optimal place in the treatment sequence being unclear. There are current ongoing studies assessing the impact of radiation as an adjunct or in place of chemotherapy. Targeted treatments (e.g., trastuzumab for human epidermal growth factor receptor 2 positive tumors and pembrolizumab for programmed death-ligand 1 positive tumors) are showing promise and are part of a continued emphasis on individualized care. Intraperitoneal chemotherapy may also play a role in preventing peritoneal recurrences for patients with high risk lesions. The treatment of patients with advanced gastric cancer in the West continues to advance and improve with a better understanding of optimal treatment sequences and the utilization of personalized treatment regimens.

Role of Radiotherapy in the Treatment of Hepatocellular Carcinoma

The role of radiotherapy in the treatment of hepatocellular carcinoma (HCC) has evolved over the past few decades with the advancement of technology and improved imaging. Radiotherapy can offer high local control rates in unresectable HCC, including cases with major vascular involvement, and can provide a modality to help bridge patients to potentially curative resection or transplantation. In metastatic cases, radiotherapy can provide good palliation. This review focuses on the common radiotherapy treatment modalities used for HCC, provides outcome comparisons of these radiotherapy techniques to outcomes with other treatment modalities for HCC, and highlights the discrepancy of the role of radiotherapy in HCC amongst the current available treatment guidelines.

Proton beam therapy outcomes for localized unresectable hepatocellular carcinoma

BACKGROUND AND PURPOSE

This study documents the utilization and efficacy of proton beam therapy (PBT) in western patients with localized unresectable hepatocellular carcinoma (HCC).

METHODS AND METHODS

Forty-six patients with HCC, Child-Pugh class of A or B, no prior radiotherapy history, and ECOG performance status 0-2 received PBT at our institution from 2007 to 2016. Radiographic control within the PBT field (local control, LC) and overall survival (OS) were calculated from the start of PBT.

RESULTS

Most (83%) patients had Child-Pugh class A. Median tumor size was 6 cm (range, 1.5-21.0 cm); 22% of patients had multiple tumors and 28% had tumor vascular thrombosis. Twenty-five (54%) patients received prior treatment. Median biologically effective dose (BED) was 97.7 GyE (range, 33.6-144 GyE) administered in 15 fractions. Actuarial 2-year LC and OS rates were 81% and 62% respectively; median OS was 30.7 months. Out-of-field intrahepatic failure was the most common site of disease progression. Patients receiving BED ≥90 GyE had a significantly better OS than those receiving BED <90 GyE (49.9 vs. 15.8 months, p = 0.037). A trend toward 2-year LC improvement was observed in patients receiving BED ≥90 GyE compared with those receiving BED <90 GyE (92% vs. 63%, p = 0.096). On multivariate analysis, higher BED (p = 0.023; hazard ratio = 0.308) significantly predicted improved OS. Six (13%) patients experienced acute grade 3 toxicity.

CONCLUSIONS

High-dose PBT is associated with high rates of LC and OS for unresectable HCC. Dose escalation may further improve outcomes.

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.

Post-transcription mediated Snail stabilization is involved in radiation exposure induced invasion and migration of hepatocarcinoma cells

Increasing evidences suggested that radiotherapy can paradoxically promote tumor invasion and metastatic processes, while its detailed mechanism is not well illustrated. Our present study found that radiation can promote the migration and invasion of hepatocellular carcinoma (HCC) cells via induction of epithelial mesenchymal transition (EMT), which was evidenced by the results that radiation induced up regulation of vimentin while down regulation of E-Cadherin. As to the EMT-related transcription factors, radiation increased the expression of Snail, while not Slug, ZEB1 or TWIST. This was confirmed by the results that radiation increased the nuclear translocation of Snail in HCC cells. However, radiation had no effect on the expression or half-life of Snail mRNA. In HCC cells treated by cycloheximide (CHX, the translation inhibitor), radiation significantly increased the half-life of Snail protein, which suggested that radiation increased the expression of Snail via up regulation of its protein stability. Radiation increased the expression of COP9 signalosome 2 (CSN2), which has been reported to block the ubiquitination and degradation of Snail. Silence of CSN2/Snail can attenuate radiation induced cell migration and EMT of HCC cells. Collectively, our data suggested that radiation can promote HCC cell invasion and EMT by stabilization of Snail via CSN2 signals.

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.

Particle radiotherapy, a novel external radiation therapy, versus liver resection for hepatocellular carcinoma accompanied with inferior vena cava tumor thrombus: A matched-pair analysis

BACKGROUND

Hepatocellular carcinoma accompanied with inferior vena cava tumor thrombus carries a dismal prognosis, and the feasibility of local treatment has remained controversial. The present study aimed to compare the outcomes of particle radiotherapy and liver resection in patients with hepatocellular carcinoma with inferior vena cava tumor thrombus.

METHODS

Thirty-one and 19 patients, respectively, underwent particle radiotherapy and liver resection for hepatocellular carcinoma with inferior vena cava tumor thrombus. A matched-pair analysis was undertaken to compare the short- and long-term outcomes according to tumor stage determined using the tumor-node-metastasis classification.

RESULTS

Both stages IIIB and IV (IVA and IVB) patients were well-matched for 12 factors, including treatment policy and patient and tumor characteristics. The median survival time of matched patients with stage IIIB tumors in the particle radiotherapy group was greater than that in the liver resection group (748 vs 272 days, P = .029), whereas no significant difference was observed in the median survival times of patients with stage IV tumors (239 vs 311 days, respectively). There were significantly fewer treatment-related complications of grade 3 or greater in the particle radiotherapy group (0%) than in the liver resection group (26%).

CONCLUSION

Particle radiotherapy is potentially preferable in hepatocellular carcinoma patients with stage IIIB inferior vena cava tumor thrombus and at least equal in efficiency to liver resection in those with stage IV disease, while causing significantly fewer complications. Considering the relatively high survival and low invasiveness of particle radiotherapy when compared to liver resection, this approach may represent a novel treatment modality for hepatocellular carcinoma with inferior vena cava tumor thrombus.

A systematic review of publications on charged particle therapy for hepatocellular carcinoma

Charged particle therapy (proton beam therapy and carbon ion therapy) is a form of radiotherapy which has the unique characteristic of superior depth dose distribution, and has been used for the treatment of hepatocellular carcinoma (HCC) in a limited number of patients, especially in Japan. We undertook a systematic review to define the clinical utility of charged particle therapy for patients with HCC. We searched the MEDLINE database from 1983 to June 2016 to identify clinical studies on charged particle therapy for HCC. Primary outcomes of interest were local control, overall survival, and late radiation morbidities. A total of 13 cohorts from 11 papers were selected from an initial dataset of 78 papers. They included a randomized controlled trial comparing proton beam therapy with transarterial chemoembolization, 9 phase I or II trials and 2 retrospective studies. The reported actuarial local control rates ranged from 71.4-95% at 3 years, and the overall survival rates ranged from 25-42.3% at 5 years. Late severe radiation morbidities were uncommon, and a total of 18 patients with grade ≥3 late adverse events were reported among the 787 patients included in this analysis. Charged particle therapy for HCC was associated with good local control with limited probability of severe morbidities. The cost-effectiveness and the distinctive clinical advantages of charged particle therapies should be clarified in order to become a socially accepted treatment modality for HCC.

Follow-up study of liver metastasis from breast cancer treated by proton beam therapy

Liver metastasis from breast cancer (LMBC) is an incurable, fatal disease with a very poor prognosis. Although various local treatments have been applied, their clinical utility has not been established. The purpose of this study was to investigate the safety and effectiveness of proton beam therapy (PBT) for the treatment of patients with LMGC. A total of 8 female patients (aged 38-63 years) with LMBC who received PBT between 2002 and 2012 were retrospectively reviewed. Patients who had tumors confined to the liver were investigated, whereas patients with extrahepatic tumors were excluded. A total of 5 patients had solitary tumors and 3 had multiple tumors. The total irradiation dose was 66-72.6 Gray equivalent [Gy relative biological effectiveness (RBE)] and 2 patients received concurrent chemotherapy or hormone therapy. The overall and progression-free survival (OS and PFS) rates, local control (LC) rate and adverse effects were investigated. All the patients completed treatment without interruption and late adverse effects of grade >3 were not observed. The OS rate was 88/73/58%, the PFS rate was 50/25/0% and the LC rate was 86/86/86% at 1/3/5 years, respectively. Thus, PBT is a safe treatment and the OS and PFS rates are comparable to those with other local treatments. PBT may be considered as an effective local treatment option for the treatment of LMBC patients.

Proton beam therapy for liver metastases from gastric cancer

Liver metastases from gastric cancer (LMGC) is a non-curable, fatal disease with a 5-year survival rate of <10%. Although various local treatments have been applied, their clinical utility has not been established. The purpose of this study was to investigate the safety and effectiveness of proton beam therapy (PBT) for the treatment of patients with LMGC. A total of nine patients (seven men, two women; aged 56-78 years) with LMGC who received PBT between 2002 and 2012 were retrospectively reviewed. Patients who had tumors confined to the liver were investigated, and patients who had extrahepatic tumors were excluded. Six of the patients had solitary tumors, and three patients had multiple tumors. The total irradiation dose was 64-77 Gy relative biological effectiveness (RBE), and three patients received concurrent chemotherapy. The overall and progression-free survival (OS and PFS) rates, local control (LC) rate, and adverse effects were investigated. All patients completed treatment without interruption, and late adverse effects of higher than Grade 3 were not observed. The OS rates at 1, 3 and 5 years were 100%, 78% and 56%, respectively (median, 5.5 years); the PFS rates were 67%, 40% and 40% (median, 2.6 years); and the LC rates were 89%, 71% and 71%. PBT was demonstrated to be a safe treatment, and the OS and PFS rates were not inferior to those for other types of local treatment. Therefore, PBT should be considered as an effective local treatment option for patients with LMGC.

Application of radiotherapy for hepatocellular carcinoma in current clinical practice guidelines

In oncologic practice, treatment guidelines provide appropriate treatment strategies based on evidence. Currently, many guidelines are used, including those of the European Association for the Study of the Liver and European Organization for Research and Treatment of Cancer (EASL-EORTC), National Comprehensive Cancer Network (NCCN), Asia-Pacific Primary Liver Cancer Expert (APPLE), and Korean Liver Cancer Study Group and National Cancer Centre (KLCSG-NCC). Although radiotherapy is commonly used in clinical practice, some guidelines do not accept it as a standard treatment modality. In this review, we will investigate the clinical practice guidelines currently used, and discuss the application of radiotherapy.

Technical advances in external radiotherapy for hepatocellular carcinoma

Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma (HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy (IMRT), stereotactic ablative body radiotherapy (SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.

Consensus for Radiotherapy in Hepatocellular Carcinoma from The 5th Asia-Pacific Primary Liver Cancer Expert Meeting (APPLE 2014): Current Practice and Future Clinical Trials

A consensus meeting to develop practice guidelines and to recommend future clinical trials for radiation therapy (RT), including external beam RT (EBRT), and selective internal RT (SIRT) in hepatocellular carcinoma (HCC) was held at the 5th annual meeting of the Asia-Pacific Primary Liver Cancer Expert consortium. Although there is no randomized phase III trial evidence, the efficacy and safety of RT in HCC has been shown by prospective and retrospective studies using modern RT techniques. Based on these results, the committee came to a consensus on the utility and efficacy of RT in the management of HCC according to each disease stage as follows: in early and intermediate stage HCC, if standard treatment is not compatible, RT, including EBRT and SIRT can be considered. In locally advanced stage HCC, combined EBRT with transarterial chemoembolization or hepatic arterial infusion chemotherapy, and SIRT can be considered. In terminal stage HCC, EBRT can be considered for palliation of symptoms and reduction of morbidity caused by the primary tumor or its metastases. Despite the currently reported benefits of RT in HCC, the committee agreed that there is a compelling need for large prospective studies, including randomized phase III trial evidence evaluating the role of RT. Specifically studies evaluating the efficacy and safety of sequential combination of EBRT and SIRT are strongly recommended.

Clinical Applications of Proton Radiation Treatment at Loma Linda University: Review of a Fifteen-year Experience

Proton radiation therapy has been used at Loma Linda University Medical Center for 15 years, sometimes in combination with photon irradiation, surgery, and chemotherapy, but often as the sole modality. Our initial experience was based on established studies showing the utility of protons for certain management problems, but since then we have engaged in a planned program to exploit the capabilities of proton radiation and expand its applications in accordance with progressively accumulating clinical data. Our cumulative experience has confirmed that protons are a superb tool for delivering conformal radiation treatments, enabling delivery of effective doses of radiation and sparing normal tissues from radiation exposure.

Considerations in Identifying Optimal Particles for Radiation Medicine

Of the many ionizing particles discovered so far, only a few are reasonable to consider for radiation therapy. These include photons, protons, neutrons, electrons, mesons, antiprotons, and ions heavier than hydrogen. Most of these particles are used therapeutically to destroy or inactivate malignant and sometimes benign cells. Since the late 1930s, accelerators have been developed that have expanded radiation oncologists' abilities to produce various ionizing particle beams. Over the past decade, radiation oncologists have become increasingly interested in pursuing particles other than the conventional photons that have been used almost exclusively since X-rays were discovered in 1895. Physicians recognize that normal-tissue morbidity from all forms of anti-cancer treatment is the primary factor limiting the success of those treatments. In radiation therapy, all particles mentioned above can destroy any cancer cell; controlling the beam in three dimensions, thus providing the physician with the capability of avoiding normal-tissue injury, is the fundamental deficiency in the use of X-rays (photons). Heavy charged particles possess near-ideal characteristics for exercising control in three dimensions; their primary differences are due to the number of protons contained within their nuclei. As their number of protons increase (atomic number) their ionization density (LET) increases. In selecting the optimal particle for therapy from among the heavy charged particles, one must carefully consider the ionization density created by each specific particle. Ionization density creates both advantages and disadvantages for patient treatment; these factors must be matched with the patients' precise clinical needs. The current state of the art involves studying the clinical advantages and disadvantages of the lightest ion, the proton, as compared to other particles used or contemplated for use. Full analysis must await adequate data developed from long-term studies to determine the precise role of each potential particle for human use. It is expected that one particle beam will emerge as the mainstream for treating human disease, and a small number of particles may emerge in an adjunctive role.

Stereotactic body radiation therapy for hepatocellular carcinoma

Stereotactic body radiotherapy (SBRT), in which highly conformal potent radiation doses are delivered in fewer fractions than traditional radiation therapy (RT), is an increasingly popular treatment for hepatocellular carcinoma (HCC). The great majority of HCCs smaller than 6 cm and with Child-Pugh A liver function are controlled with SBRT with limited toxicity. Long-term local control is reduced in larger tumors, and toxicity is increased in patients with Child-Pugh B or C liver function. SBRT is an effective treatment for tumor vascular thrombi and can lead to sustained vascular recanalization. The first site of recurrence following SBRT is most often within the liver, away from the high dose volume, providing rationale for combining SBRT with regional or systemic therapies. Randomized trials of SBRT are warranted.

Proton Beam Therapy for Hepatocellular Carcinoma: A Review of the University of Tsukuba Experience

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death worldwide. Many treatment modalities were developed for HCC, including surgical resection, percutaneous ethanol injection, radiofrequency ablation, transarterial chemoembolization, liver transplantation, and sorafenib therapy. Our institution has shown that proton beam therapy (PBT) is also a safe, effective, and feasible treatment modality for HCC. The University of Tsukuba began to use PBT for HCC in 1983, and we have reported many findings during the past 3 decades. In this review, we will describe the history of PBT, our experience of using PBT for HCC, and its application based on tumor location, thrombosis, tumor size, and liver function.

Proton beam therapy for metastatic liver tumors

PURPOSE

The purpose of this study was to investigate the safety and efficacy of proton beam therapy (PBT) for the treatment of metastatic liver tumors.

MATERIAL AND METHODS

A total of 140 patients with liver metastasis who received PBT were retrospectively investigated. The main primary tumor sites were the colorectum (60) and the pancreas (19).

RESULTS

One hundred thirty-three patients (95%) completed treatment. Two patients experienced late adverse effects (rib fracture and cholangitis). The 5-year overall survival (OS) rate was 24%. In the 85 patients with lesions confined to the liver, the 5-year OS rate of was 28%, and in the 55 patients with lesions both inside and outside the liver, it was 16% (P=0.007). Among the patients with lesions confined to the liver, the 5-year OS rate of the 62 patients who received curative treatment was 30%, and that of the 23 patients who received palliative treatment, 23% (P=0.016). Multivariate analysis showed that the treatment strategy (curative and palliative) alone was associated with the OS rate (P=0.02).

CONCLUSION

PBT is a potentially safe and effective treatment for metastatic liver tumors.

Charged particle therapy versus photon therapy for patients with hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis to compare the clinical outcomes and toxicity of hepatocellular carcinoma (HCC) patients treated with charged particle therapy (CPT) with those of individuals receiving photon therapy.

METHODS

We identified relevant clinical studies through searching databases. Primary outcomes of interest were overall survival (OS) at 1, 3, 5 years, progression-free survival (PFS), and locoregional control (LC) at longest follow-up.

RESULTS

73 cohorts from 70 non-comparative observational studies were included. Pooled OS was significantly higher at 1, 3, 5 years for CPT than for conventional radiotherapy (CRT) [relative risk (RR) 1·68, 95% CI 1·22-2·31; p<0·001; RR 3.46, 95% CI: 1.72-3.51, p<0.001; RR 25.9, 95% CI: 1.64-408.5, p=0.02; respectively]. PFS and LC at longest follow-up was also significantly higher for CPT than for CRT (p=0·013 and p<0.001, respectively), while comparable efficacy was found between CPT and SBRT in terms of OS, PFS and LC at longest follow-up. Additionally, high-grade acute and late toxicity associated with CPT was lower than that of CRT and SBRT.

CONCLUSION

Survival rates for CPT are higher than those for CRT, but similar to SBRT in patients with HCC. Toxicity tends to be lower for CPT compared to photon radiotherapy.

Considerations for radiation therapy in hepatocellular carcinoma: the radiation oncologists' perspective

Although the Barcelona Clinic Liver Cancer staging system does not recommend radiation therapy (RT) as a locoregional modality in hepatocellular carcinoma (HCC), many prospective and retrospective studies have reported excellent local control with favorable survival rates after RT using modern techniques. Additionally, there have been several comparative or meta-analysis results reporting the superiority of RT in unresectable HCC. Therefore, it might be more reasonable to apply RT in unresectable HCC as an alternative locoregional modality to improve local control in HCC. However, several considerations for the application of RT in HCC exist. The considerations for RT in HCC are purpose, combination treatment and technique. The purpose of RT should be based on baseline liver status as well as tumor extent and location. There are several reasonable advantages in local, intrahepatic and extrahepatic control when combined with other modalities, but it could lead to overtreatment in some cases. The technical considerations according to the purpose and combination modality are the final step. For the application of RT in HCC, the purpose of RT, combination strategy and technical considerations should be taken into account.

Phase I dose-escalation study of proton beam therapy for inoperable hepatocellular carcinoma

Purpose

The purpose of this study is to determine the optimal dose of proton beam therapy (PBT) in hepatocellular carcinoma (HCC) patients.

Materials and Methods

Inoperable HCC patients who had naïve, recurrent, or residual tumor to treatment were considered eligible for PBT. Patients received PBT with 60 GyE in 20 fractions (dose level 1; equivalent dose in 2 Gy fractions [EQD2], 65 GyE₁₀); 66 GyE in 22 fractions (dose level 2; EQD2, 71.5 GyE₁₀); or 72 GyE in 24 fractions (dose level 3; EQD2, 78 GyE₁₀). Dose-limiting toxicity was determined by grade ≥ 3 acute toxicity.

Results

Twenty-seven patients were enrolled; eight, seven, and 12 patients were treated with dose levels 1, 2, and 3, respectively. Overall, treatment was well tolerated, with no dose-limiting toxicities. The complete response (CR) rates of primary tumors after PBT for dose levels 1, 2, and 3 were 62.5% (5/8), 57.1% (4/7), and 100% (12/12), respectively (p=0.039). The 3-and 5-year local progression-free survival (LPFS) rates among 26 patients, excluding one patient who underwent liver transplantation after PBT due to its probable significant effect on disease control, were 79.9% and 63.9%, respectively, and the 3-and 5-year overall survival rates were 56.4% and 42.3%, respectively. The 3-year LPFS rate was significantly higher in patients who achieved CR than in those who did not (90% vs. 40%, p=0.003).

Conclusion

PBT is safe and effective and an EQD2 ≥ 78 GyE₁₀ should be delivered for achievement of local tumor control.

Role of external beam radiation therapy in management of hepatocellular carcinoma

Diagnosis at advanced disease stage and early vascular invasion are the bane of majority of patients with hepatocellular carcinoma (HCC) in India. The currently standardized curative and palliative treatment modalities [surgery, ablative techniques, trans-catheter chemotherapy, systemic chemotherapy] are suboptimal for a significant proportion of disease stages. Interest in radiotherapy for hepatocellular carcinoma has seen a resurgence with revolutionary improvements in targeting radiation doses safely. Encouraging results have been reported with a host of radiation techniques from conformal radiotherapy, stereotactic whole body radiation therapy to charged particle based therapies. The dissemination of this knowledge has been slow across other specialties involved in care of patients with HCC. However the increasing availability of radiotherapy services predicts a hopeful future for wider evaluation of radiotherapy in HCC.

Accelerated dose escalation with proton beam therapy for non-small cell lung cancer

Local tumor control remains challenging in many cases of non-small cell lung cancer (NSCLC), particularly those that involve large or centrally located tumors. Concurrent chemotherapy and radiation can maximize tumor control and survival for patients with locally advanced disease, but a substantial proportion of such patients cannot tolerate this therapy, and sequential chemoradiation regimens or radiation given alone at conventionally fractionated doses produces suboptimal results. An alternative approach is the use of hypofractionated proton beam therapy (PBT). The energy distribution of protons can be exploited to reduce involuntary irradiation of normal tissues, particularly the low-dose irradiation problematic in intensity-modulated (photon) radiation therapy (IMRT). Here we summarize current evidence on the use of hypofractionated PBT for both early-stage and locally advanced NSCLC, and the possibility of using hypofractionated regimens for patients who are not candidates for concurrent chemotherapy.

A phase I study on combined therapy with proton-beam radiotherapy and in situ tumor vaccination for locally advanced recurrent hepatocellular carcinoma

Background

Proton-beam radiotherapy (PBT) has been shown to be effective to hepatocellular carcinoma (HCC) as a nonsurgical local treatment option. However, HCC still remains as one of the most difficult cancers to be cured because of frequent recurrences. Thus, methods to inhibit the recurrence need to be explored. To prevent the HCC recurrence, we here report on a prospective phase I study of ‘in situ’ tumor vaccination using CalTUMP, a newly developed immunoadjuvant consisting of BCG extract bound to hydroxyapatite and microparticulated tuberculin, following local PBT for HCC.

Methods

Patients with locally advanced recurrent HCC, which had been heavily pretreated with various treatments, were enrolled. PBT was performed with the conventional method to the target HCC. Subsequently, CalTUMP was injected into the same irradiated-tumor three times at one-week intervals. Three dose-levels of CalTUMP (1/10, 1/3, and 1/1) were administered to 3 patients each. Vital signs, blood samples, ultrasound, and computed tomographic scans were monitored to evaluate the safety.

Results

Three intratumoral injections of CalTUMP following PBT (median dose: 72.6 GyE) were accomplished in 9 patients. Transient low-grade fever and minor laboratory changes were observed in 7 patients after CalTUMP injections. No other treatment-related adverse events were observed. Median progression-free survival was 6.0 months (range: 2.1-14.2) and 4 patients were progression-free for more than 1 year.

Conclusions

Intratumoral injection of CalTUMP following PBT was feasible and safe in patients with heavily pre-treated HCC. Further clinical studies to evaluate the efficacy of this in situ tumor vaccination are warranted.

New strategies in radiation therapy: exploiting the full potential of protons

Protons provide significant dosimetric advantages compared with photons because of their unique depth-dose distribution characteristics. However, they are more sensitive to the effects of intra- and intertreatment fraction anatomic variations and uncertainties in treatment setup. Furthermore, in the current practice of proton therapy, the biologic effectiveness of protons relative to photons is assumed to have a generic fixed value of 1.1. However, this is a simplification, and it is likely higher in different portions of the proton beam. Current clinical practice and trials have not fully exploited the unique physical and biologic properties of protons. Intensity-modulated proton therapy, with its ability to manipulate energies (in addition to intensities), provides an entirely new dimension, which, with ongoing research, has considerable potential to increase the therapeutic ratio.

Charged particle therapy--optimization, challenges and future directions

The use of charged particle therapy to control tumours non-invasively offers advantages over conventional radiotherapy. Protons and heavy ions deposit energy far more selectively than X-rays, allowing a higher local control of the tumour, a lower probability of damage to healthy tissue, low risk of complications and the chance for a rapid recovery after therapy. Charged particles are also useful for treating tumours located in areas that surround tissues that are radiosensitive and in anatomical sites where surgical access is limited. Current trial outcomes indicate that accelerated ions can potentially replace surgery for radical cancer treatments, which might be beneficial as the success of surgical cancer treatments are largely dependent on the expertise and experience of the surgeon and the location of the tumour. However, to date, only a small number of controlled randomized clinical trials have made comparisons between particle therapy and X-rays. Therefore, although the potential advantages are clear and supported by data, the cost:benefit ratio remains controversial. Research in medical physics and radiobiology is focusing on reducing the costs and increasing the benefits of this treatment.

Dose-volume histogram analysis for risk factors of radiation-induced rib fracture after hypofractionated proton beam therapy for hepatocellular carcinoma

BACKGROUND

Radiation-induced rib fracture has been reported as a late complication after external radiotherapy to the chest. The purpose of this study was to clarify the characteristics and risk factors of rib fracture after hypofractionated proton beam therapy (PBT).

MATERIAL AND METHODS

The retrospective study comprised 67 patients with hepatocellular carcinoma who were treated using PBT of 66 Cobalt-Gray-equivalents [Gy (RBE)] in 10 fractions. We analyzed the patients' characteristics and determined dose-volume histograms (DVHs) for the irradiated ribs, and then estimated relationships between risk of fracture and several dose-volume parameters. An irradiated rib was defined to be any rib included in the area irradiated by PBT as determined by treatment-planning computed tomography.

RESULTS

Among the 67 patients, a total of 310 ribs were identified as irradiated ribs. Twenty-seven (8.7%) of the irradiated ribs developed fractures in 11 patients (16.4%). No significant relationships were seen between incidence of fracture and characteristics of patients, including sex, age, tumor size, tumor site, and follow-up period (p ≥ 0.05). The results of receiver operating characteristic curve analysis using DVH parameters demonstrated that the largest area under the curve (AUC) was observed for the volume of rib receiving a biologically effective dose of more than 60 Gy(3 )(RBE) (V60) [The equivalent dose in 2 Gy fractions (EQD2); 36 Gy(3)] and the AUCs of V30 to V120 (EQD2; 18-72 Gy(3)) and Dmax to D(10 cm)(3) were similar to that of V60. No significant relationships were seen for DVH parameters and intervals from PBT to incidence of fracture.

CONCLUSION

DVH parameters are useful in predicting late adverse events of rib irradiation. This study identified that V60 was a most statistically significant parameter, and V30 to V120 and Dmax to D(10 cm)(3) were also significant and clinically useful for estimating the risk of rib fracture after hypofractionated PBT.

Proton therapy for hepatocellular carcinoma

Proton radiotherapy has seen an increasing role in the treatment of hepatocellular carcinoma (HCC). Historically, external beam radiotherapy has played a very limited role in HCC due to a high incidence of toxicity to surrounding normal structures. The ability to deliver a high dose of radiation to the tumor is a key factor in improving outcomes in HCC. Advances in photon radiotherapy have improved dose conformity and allowed dose escalation to the tumor. However, despite these advances there is still a large volume of normal liver that receives a considerable radiation dose during treatment. Proton beams do not have an exit dose along the beam path once they enter the body. The inherent physical attributes of proton radiotherapy offer a way to maximize tumor control via dose escalation while avoiding excessive radiation to the remaining liver, thus increasing biological effectiveness. In this review we discuss the physical attributes and rationale for proton radiotherapy in HCC. We also review recent literature regarding clinical outcomes of using proton radiotherapy for the treatment of HCC.

A review of update clinical results of carbon ion radiotherapy

Among various types of ion species, carbon ions are considered to have the most balanced, optimal properties in terms of possessing physically and biologically effective dose localization in the body. This is due to the fact that when compared with photon beams, carbon ion beams offer improved dose distribution, leading to the concentration of the sufficient dose within a target volume while minimizing the dose in the surrounding normal tissues. In addition, carbon ions, being heavier than protons, provide a higher biological effectiveness, which increases with depth, reaching the maximum at the end of the beam's range. This is practically an ideal property from the standpoint of cancer radiotherapy. Clinical studies have been carried out in the world to confirm the efficacy of carbon ions against a variety of tumors as well as to develop effective techniques for delivering an efficient dose to the tumor. Through clinical experiences of carbon ion radiotherapy at the National Institute of Radiological Sciences and Gesellschaft für Schwerionenforschung, a significant reduction in the overall treatment time with acceptable toxicities has been obtained in almost all types of tumors. This means that carbon ion radiotherapy has meanwhile achieved for itself a solid place in general practice. This review describes clinical results of carbon ion radiotherapy together with physical, biological and technological aspects of carbon ions.

The optimal selection of radiotherapy treatment for hepatocellular carcinoma

The majority of patients who present with hepatocellular carcinoma (HCC) are already at an advanced stage, and the tumors are unresectable. Radiotherapy (RT) technology can safely provide focused high-dose irradiation to these patients. A wide spectrum of RT technologiesis currently available, including internal RT consisting of Yttrium-90 ((90)Y), Iodine-131 ((131)I) anti-ferritin antibody and Homium-199 ((199)Ho) and external RT, such as three-dimensional conformal RT, intensity-modulated RT, helical tomotherapy, stereotactic body RT, and image-guided RT. However, it may be difficult for physicians to understand all of the available options and to select the optimal RT treatment. Physicians frequently query radiation oncologists on the practical indications of RT for managing patients with HCC. According to the Korean Liver Cancer Study Group practice guidelines, RT is considered appropriate for unresectable, locally advanced HCC without extrahepatic metastasis, a Child-Pugh class A or B, and tumors that occupy less than two-thirds of the liver with level II evidence. In this review, we discuss the application of various RT modalities based on disease status and the detailed indications for RT according to the Barcelona Clinic Liver Cancer staging system.

An evidence based review of proton beam therapy: the report of ASTRO's emerging technology committee

Proton beam therapy (PBT) is a novel method for treating malignant disease with radiotherapy. The purpose of this work was to evaluate the state of the science of PBT and arrive at a recommendation for the use of PBT. The emerging technology committee of the American Society of Radiation Oncology (ASTRO) routinely evaluates new modalities in radiotherapy and assesses the published evidence to determine recommendations for the society as a whole. In 2007, a Proton Task Force was assembled to evaluate the state of the art of PBT. This report reflects evidence collected up to November 2009. Data was reviewed for PBT in central nervous system tumors, gastrointestinal malignancies, lung, head and neck, prostate, and pediatric tumors. Current data do not provide sufficient evidence to recommend PBT in lung cancer, head and neck cancer, GI malignancies, and pediatric non-CNS malignancies. In hepatocellular carcinoma and prostate cancer and there is evidence for the efficacy of PBT but no suggestion that it is superior to photon based approaches. In pediatric CNS malignancies PBT appears superior to photon approaches but more data is needed. In large ocular melanomas and chordomas, we believe that there is evidence for a benefit of PBT over photon approaches. PBT is an important new technology in radiotherapy. Current evidence provides a limited indication for PBT. More robust prospective clinical trials are needed to determine the appropriate clinical setting for PBT.

Hepatocellular carcinoma: management of an increasingly common problem

Hepatocellular carcinoma (HCC) is a common cancer that typically occurs in the setting of cirrhosis and chronic hepatitis virus infections. Hepatitis B and C account for approximately 80% of cases worldwide. HCC is currently the fifth most common malignancy in men and the eighth in women worldwide; its incidence is increasing dramatically in many parts of the world. Recognition of those at risk and early diagnosis by surveillance with imaging, with or without serologic testing, are extremely important. Many highly effective and even curative therapies are now available and include resection, liver transplantation, and local ablation. Appropriate application of these interventions offers hope of prolonged survival to many patients with this otherwise lethal complication of liver disease.

Charged-particle therapy for hepatocellular carcinoma

Historically, the use of external-beam radiotherapy for hepatocellular carcinoma (HCC) has been limited by toxicity to the uninvolved liver and surrounding structures. Advances in photon radiotherapy have improved dose conformality to the tumor and facilitated dose escalation, a key contributor to improved HCC radiation treatment outcomes. However, despite these advances in photon radiotherapy, significant volumes of liver still receive low doses of radiation that can preclude dose escalation, particularly in patients with limited functional liver reserves. By capitalizing on the lack of exit dose along the beam path beyond the tumor and higher biological effectiveness, charged-particle therapy offers the promise of maximizing tumor control via dose escalation without excessive liver toxicity. In this review, we discuss the distinctive biophysical attributes of both proton and carbon ion radiotherapy, particularly as they pertain to treatment of HCC. We also review the available literature regarding clinical outcomes and the toxicity of using charged particles for the treatment of HCC.