Hepatocellular carcinoma radiation therapy: review of evidence and future opportunities

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

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

Nifuroxazide suppresses PD-L1 expression and enhances the efficacy of radiotherapy in hepatocellular carcinoma

Radiation therapy is a primary treatment for hepatocellular carcinoma (HCC), but its effectiveness can be diminished by various factors. The over-expression of PD-L1 has been identified as a critical reason for radiotherapy resistance. Previous studies have demonstrated that nifuroxazide exerts antitumor activity by damaging the Stat3 pathway, but its efficacy against PD-L1 has remained unclear. In this study, we investigated whether nifuroxazide could enhance the efficacy of radiotherapy in HCC by reducing PD-L1 expression. Our results showed that nifuroxazide significantly increased the sensitivity of tumor cells to radiation therapy by inhibiting cell proliferation and migration while increasing apoptosis in vitro. Additionally, nifuroxazide attenuated the up-regulation of PD-L1 expression induced by irradiation, which may be associated with increased degradation of PD-L1 through the ubiquitination-proteasome pathway. Furthermore, nifuroxazide greatly enhanced the efficacy of radiation therapy in H22-bearing mice by inhibiting tumor growth, improving survival, boosting the activation of T lymphocytes, and decelerating the ratios of Treg cells in spleens. Importantly, nifuroxazide limited the increased expression of PD-L1 in tumor tissues induced by radiation therapy. This study confirms, for the first time, that nifuroxazide can augment PD-L1 degradation to improve the efficacy of radiation therapy in HCC-bearing mice.

Clinical benefits of intraoperative radiotherapy for the recurrence of centrally located hepatocellular carcinoma with microvascular invasion

BACKGROUND

Although the efficacy and safety of intraoperative radiotherapy (IORT) in the treatment of malignant tumours, such as breast cancer, have been documented, it remains unclear whether this treatment is effective for centrally located hepatocellular carcinoma (HCC) with microvascular invasion (MVI).

AIMS

This study aimed to explore the efficacy and safety of IORT in the treatment of centrally located HCC with MVI.

METHODS AND RESULTS

Patients with centrally located HCC, who underwent surgery between January 2016 and January 2020, were enrolled. The patient cohort was then allocated to two groups: those who underwent IORT combined with liver resection (IORT+LR); or LR alone (LR). Propensity score matching and Cox proportional hazards regression analyses were performed. The Kaplan-Meier method was used to estimate recurrence-free survival (RFS), and the log-rank test was used to determine whether RFS differed between the groups. Subgroup analysis was performed to evaluate differences in RFS and early recurrence rates in patients with different MVI grades. E-values were generated to measure the sensitivity to unmeasured confounding factors. In total, 97 patients were enrolled, 27 of whom underwent IORT+LR and 70 underwent LR alone. The 1-, 3-, and 5-year RFS rates in the IORT+LR group were 66%, 50%, and 32%, respectively, whereas those in the LR group were 54%, 37%, and 26%, respectively. After matching analysis, 23 patients were successfully matched, and RFS was found to be significantly different between the two groups (p = .04). IORT was an independent prognostic factor for RFS (hazard ratio 0.46 [95% confidence interval 0.21-0.99]). In subgroup analysis, RFS between the IORT+LR and LR groups was significantly different in patients with MVI (M1 grade) (p = .0067). The postoperative early recurrence rate was significantly reduced with IORT (p < .05). No serious complications were reported in either group following surgery. Based on E-values, the results appeared to be robust against unmeasured confounding factors.

CONCLUSION

IORT+LR provided safe, feasible treatment for patients with centrally located HCC with MVI, along with an improvement in prognosis and lower early recurrence rates.

Advances in radiotherapy and immunity in hepatocellular carcinoma

Primary liver cancer is one of the most common malignant tumours worldwide; it caused approximately 830,000 deaths in 2020. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for over 80% of all cases. Various methods, including surgery, chemotherapy, radiotherapy, and radiofrequency ablation, have been widely used in the treatment of HCC. With the advancement of technology, radiotherapy has become increasingly important in the comprehensive treatment of HCC. However, due to the insufficient sensitivity of tumour cells to radiation, there are still multiple limitation in clinical application of radiotherapy. In recent years, the role of immunotherapy in cancer has been increasingly revealed, and more researchers have turned their attention to the combined application of immunotherapy and radiotherapy in the hope of achieving better treatment outcomes. This article reviews the progress on radiation therapy in HCC and the current status of its combined application with immunotherapy, and discusses the prospects and value of radioimmunotherapy in HCC.

Fisetin, an Anti-Inflammatory Agent, Overcomes Radioresistance by Activating the PERK-ATF4-CHOP Axis in Liver Cancer

Fisetin, a well-known plant flavonol from the natural flavonoid group, is found in traditional medicines, plants, vegetables, and fruits. Fisetin also has anti-oxidant, anti-inflammatory, and anti-tumor effects. This study investigated the anti-inflammatory effects of fisetin in LPS-induced Raw264.7 cells and found that fisetin reduced the LPS-induced production of pro-inflammation markers, such as TNF-α, IL-1β, and IL-6, demonstrating the anti-inflammatory effects of fisetin. Furthermore, this study investigated the anti-cancer effects of fisetin and found that fisetin induced apoptotic cell death and ER stress through intracellular calcium (Ca²⁺) release, the PERK-ATF4-CHOP signaling pathway, and induction of GRP78 exosomes. However, the suppression of PERK and CHOP inhibited the fisetin-induced cell death and ER stress. Interestingly, fisetin induced apoptotic cell death and ER stress and inhibited the epithelial-mesenchymal transition phenomenon under radiation in radiation-resistant liver cancer cells. These findings indicate that the fisetin-induced ER stress can overcome radioresistance and induce cell death in liver cancer cells following radiation. Therefore, the anti-inflammatory agent fisetin, in combination with radiation, may be a powerful immunotherapy strategy to overcome resistance in an inflammatory tumor microenvironment.

Inactivation of EGFR/ERK/NF-κB signalling associates with radiosensitizing effect of 18β-glycyrrhetinic acid on progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is recognized as the fifth most common cancer and the third most common cause of death in Asian population. Studies reported that HCC is relatively insensitive to radiotherapy (RT); thus, considering how to sensitize HCC to RT is worth to be elucidated. Epidermal growth factor receptor (EGFR)-mediated signalling transduction plays the important role in regulating treatment efficacy of HCC. An active compound, 18beta-glycyrrhetinic acid (18β-GA), has been reported to own anti-tumour effect. However, whether 18β-GA possess RT sensitization ability in HCC remains unclear. Here, we used RNA data from TCGA-LIHC (Liver hepatocellular carcinoma) to identify the role between EGFR/ERK/nuclear factor kappa B (NF-κB) signalling and RT by radiosensitivity index (RSI) analysis. We suggested that patients with activated NF-κB signalling may show resistance to RT treatment, whereas combining 18β-GA may reinforce RT efficacy in a Hep3B-bearing animal model. 18β-GA combined with RT showed superior tumour inhibition capacity as compared to monotherapy and even reached similar efficacy as erlotinib combined with RT. Treatment promotion of RT by 18β-GA in HCC is not only through diminishing RT-induced EGFR/ERK/NF-κB signalling but also promoting RT-induced apoptosis pathways. 18β-GA may act as radiosensitizer through inactivating EGFR-mediated HCC progression and inducing caspase-dependent apoptosis signalling.

Survival benefit of radiotherapy following narrow-margin hepatectomy in patients with hepatocellular carcinoma: A propensity score-matched analysis based on phase II study

BACKGROUND AND PURPOSE

We evaluated the postoperative radiotherapy (PORT) effects on hepatocellular carcinoma (HCC) prognosis and recurrence in patients who underwent narrow-margin (<1.0 cm) hepatectomy (NH).

MATERIALS AND METHODS

This two-arm cohort study based on the phase II study compared NH with or without PORT in patients with HCC. All patients underwent NH; 76 patients who received PORT following NH in the phase II study were assigned to the NH + RT group, and 171 who underwent NH alone were assigned to the NH group. Propensity score matching (PSM) was used to balance clinicopathological characteristic differences between groups.

RESULTS

Before PSM, the 5-year overall survival (OS) rates between groups differed significantly (72.2 % vs 60.7 %, P = 0.017). Moreover, the 5-year disease-free survival (DFS) rate was significantly higher in the NH + RT group (51.4 % vs 35.7 %, P = 0.002). After PSM, the between-group difference in OS rates remained high (P = 0.045); the 5-year OS rates were 74.7 % and 63.6 % in the NH + RT and NH groups, respectively. Similarly, the DFS rate remained significantly higher in the NH + RT group (P = 0.001); the 5-year DFS rates were 56.3 % and 31.6 %, respectively. Furthermore, both before and after PSM, patients in the NH + RT group showed significantly lower early, intrahepatic, and extrahepatic recurrence rates than those in the NH group.

CONCLUSIONS

PORT may have significant OS and DFS benefits in patients with HCC undergoing NH.

Liver SBRT dose accumulation to assess the impact of anatomic variations on normal tissue doses and toxicity in patients treated with concurrent sorafenib

BACKGROUND AND PURPOSE

Unexpected liver volume reductions occurred during trials of liver SBRT and concurrent sorafenib. The aims were to accumulate liver SBRT doses to assess the impact of these anatomic variations on normal tissue dose parameters and toxicity.

MATERIALS AND METHODS

Thirty-two patients with hepatocellular carcinoma (HCC) or metastases treated on trials of liver SBRT (30-57 Gy, 6 fractions) and concurrent sorafenib were analyzed. SBRT doses were accumulated using biomechanical deformable registration of daily cone-beam CT. Dose deviations (accumulated-planned) for normal tissues were compared for patients with liver volume reductions > 100 cc versus stable volumes, and accumulated doses were reported for three patients with grade 3-5 luminal gastrointestinal toxicities.

RESULTS

Patients with reduced (N = 12) liver volumes had larger mean deviations of 0.4-1.3 Gy in normal tissues, versus -0.2-0.4 Gy for stable cases (N = 20), P > 0.05. Deviations > 5% of the prescribed dose occurred in both groups. Two HCC patients with toxicities to small and large bowel had liver volume reductions and deviations to the maximum dose of 4% (accumulated 36.9 Gy) and 3% (accumulated 33.4 Gy) to these organs respectively. Another HCC patient with a toxicity of unknown location plus tumor rupture, had stable liver volumes and deviations to luminal organs of -6% to 4.5% (accumulated < 30.5 Gy).

CONCLUSION

Liver volume reductions during SBRT and concurrent sorafenib were associated with larger increases in accumulated dose to normal tissues versus stable liver volumes. These dosimetric changes may have further contributed to toxicities in HCC patients who have higher baseline risks.

The Expression of Connexin 26 Regulates the Radiosensitivity of Hepatocellular Carcinoma Cells through a Mitogen-Activated Protein Kinases Signal Pathway

Connexin 26 (Cx26) is a protein that constitutes a gap junction and is widely expressed in the liver. Abnormal expression of Cx26 is one of the important mechanisms of liver cancer, and is closely related to the transmission of radiation damage signals between cells. In the present study, we investigated the radiosensitivity of hepatocellular carcinoma (HCC) cells HepG2, with low expression of Cx26, and SK-hep-1, with high expression of Cx26 after X-ray irradiation. The cell survival, micronucleus formation and protein expressions of the mitogen-activated protein kinases (MAPK) signaling pathway were detected. The expression level of Cx26 could affect the radiosensitivity of liver cancer cells by affecting the phosphorylation of p38 and ERK proteins and regulating the expression of downstream NF-κB. Cell lines with knock-out and overexpression of Cx26 were also built to confirm the findings. Our results suggested that Cx26 might play an important role in the radiosensitivity of liver cancer and could be a potential target for clinical radiotherapy of liver cancer.

NUPR1 contributes to radiation resistance by maintaining ROS homeostasis via AhR/CYP signal axis in hepatocellular carcinoma

BACKGROUND

Radiotherapy (RT) is one of the major therapeutic approaches to hepatocellular carcinoma (HCC). Ionizing radiation (IR) inducing the generation of reactive oxygen species (ROS) leads to a promising antitumor effect. However, the dysregulation of the redox system often causes radioresistance and impairs the efficacy of RT. Increasing evidence indicates that nuclear protein 1 (NUPR1) plays a critical role in redox reactions. In this study, we aim to explore the role of NUPR1 in maintaining ROS homeostasis and radioresistance in HCC.

METHODS

The radioresistant role of NUPR1 was determined by colony formation assay, comet assay in vitro, and xenograft tumor models in vivo. Probes for ROS, apoptosis assay, and lipid peroxidation assay were used to investigate the functional effect of NUPR1 on ROS homeostasis and oxidative stress. RNA sequencing and co-immunoprecipitation assay were performed to clarify the mechanism of NUPR1 inhibiting the AhR/CYP signal axis. Finally, we analyzed clinical specimens to assess the predictive value of NUPR1 and AhR in the radiotherapeutic efficacy of HCC.

RESULTS

We demonstrated that NUPR1 was upregulated in HCC tissues and verified that NUPR1 increased the radioresistance of HCC in vitro and in vivo. NUPR1 alleviated the generation of ROS and suppressed oxidative stress, including apoptosis and lipid peroxidation by downregulating cytochrome P450 (CYP) upon IR. ROS scavenger N-acetyl-L-cysteine (NAC) and CYP inhibitor alizarin restored the viability of NUPR1-knockdown cells during IR. Mechanistically, the interaction between NUPR1 and aryl hydrocarbon receptor (AhR) promoted the degradation and decreased nuclear translation of AhR via the autophagy-lysosome pathway, followed by being incapable of CYP's transcription. Furthermore, genetically and pharmacologically activating AhR abrogated the radioresistant role of NUPR1. Clinical data suggested that NUPR1 and AhR could serve as novel biomarkers for predicting the radiation response of HCC.

CONCLUSIONS

Our findings revealed the role of NUPR1 in regulating ROS homeostasis and oxidative stress via the AhR/CYP signal axis upon IR. Strategies targeting the NUPR1/AhR/CYP pathway may have important clinical applications for improving the radiotherapeutic efficacy of HCC.

Conversion Therapy of Large Unresectable Hepatocellular Carcinoma With Ipsilateral Portal Vein Tumor Thrombus Using Portal Vein Embolization Plus Transcatheter Arterial Chemoembolization

Background

The study aimed to assess the safety and efficacy of conversion therapy with portal vein embolization (PVE) and transcatheter arterial chemoembolization (TACE) in patients with large unresectable hepatocellular carcinoma (HCC) and ipsilateral portal vein tumor thrombus (PVTT).

Methods

This retrospective study evaluated consecutive patients with initially large (≥5 cm) unresectable HCC with ipsilateral PVTT who underwent PVE + TACE at our center between June 2016 and September 2020 (Group A). Clinically equivalent patients from three centers who were receiving tyrosine kinase inhibitors (TKIs) + TACE (Group B) were included. The survival times were evaluated and compared between the two therapeutic groups.

Results

In Group A (n = 33), the median tumor diameter was 14 cm (range, 5–18 cm) and 19 (57.6%) patients underwent radical resection 18–95 days after PVE. Radical liver resection was not performed because of inadequate hypertrophy (n = 11), pulmonary metastasis (n = 1), lack of consent for surgery (n = 1), and the rupture of the HCC (n = 1). There were no patients who underwent radical resection in Group B (n = 64) (P = 0.000). The mean and median overall survival (OS) were 736.5 days and 425.0 days in Group A and 424.5 days and 344.0 days in Group B, respectively. Compared with TKIs + TACE, treatment with PVE + TACE prolonged OS (P = 0.023).

Conclusions

This study shows that conversion therapy was safe and effective in patients with initially large unresectable HCC with ipsilateral PVTT treated with PVE + TACE. Moreover, PVE + TACE conferred more favorable outcomes than treatment with TKIs + TACE.

Verbascoside enhances radiosensitivity of hepatocellular carcinoma cells through regulating miR-101-3p/Wee1 axis

Verbascoside is a kind of phenylpropanoid glycoside derived from multiple medicinal plants, exerting anti-tumor effects in diverse human malignancies. However, the function of Verbascoside on the radiosensitivity of hepatocellular carcinoma (HCC) cells remains unknown. Human Huh7 and HepG2 cell lines were treated with Verbascosideis, and cell viability was detected with cell counting kit-8 (CCK-8) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect miR-101-3p expression, and Western blot was used to quantify the expression of WEE1 G2 checkpoint kinase (WEE1). Then, CCK-8 and flow cytometry assays were used to detect the proliferation and apoptosis of HCC cells after Verbascoside and X-ray combined treatment, and the expressions of WEE1 and apoptosis-related proteins Bax and Bcl-2 were detected by Western blot. Verbascoside could improve the radiosensitivity of HCC cells in a dose-dependent manner. Verbascoside increased the expression of miR-101-3p but reduced WEE1 expression in HCC cells. Additionally, WEE1 was identified as a target of miR-101-3p. MiR-101-3p inhibition or WEE1 overexpression could reverse the effect of Verbascoside on the viability and apoptosis of HCC cells. Verbascoside increases the radiosensitivity of hepatocellular carcinoma cells via modulating miR-101-3p/WEE1 axis.

Liver-Directed Concurrent Chemoradiotherapy versus Sorafenib in Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis

Simple Summary

We investigated the efficacy of liver-directed concurrent chemoradiotherapy compared with sorafenib in hepatocellular carcinoma patients with portal vein tumor thrombosis. Patients in the sorafenib group presented higher incidences of unfavorable clinical features, and propensity score matching was performed to compensate for the differences between the two groups. We found that liver-directed concurrent chemoradiotherapy resulted in significantly improved survival compared to the sorafenib group. 3.6% and 13.8% of patients in the sorafenib and liver-directed concurrent chemoradiotherapy groups underwent surgical treatment after initial treatment, and those who received surgical treatment had significantly longer overall survival.

Abstract

This study aimed to investigate the efficacy of liver-directed concurrent chemoradiotherapy (LD-CCRT) compared with sorafenib in patients with liver-confined locally advanced hepatocellular carcinoma (HCC) presenting portal vein tumor thrombosis (PVTT). This single institute retrospective cohort study included patients treated with sorafenib or LD-CCRT between 2005 and 2016. Patients with extrahepatic disease and those without PVTT were excluded, leaving 28 and 448 patients in the sorafenib and LD-CCRT groups, respectively. Propensity score matching was performed to balance the differences in clinical features between the two groups. At baseline, the sorafenib group presented higher incidences of unfavorable clinical features, including type III-IV PVTT (53.6% vs. 30.6%, p = 0.048) and bilateral disease extent (64.3% vs. 31.5%, p = 0.001), than the LD-CCRT group. A total of 27 patients from the sorafenib group and 52 patients from the LD-CCRT group were matched. At a median follow-up of 73 months, the median overall survival (OS) was 4.3 and 9.8 months in the sorafenib and LD-CCRT groups, respectively (p = 0.002). Patients with PVTT type II and higher benefited more from LD-CCRT in terms of OS. The Cox proportional hazard model showed that LD-CCRT was a significant prognostic factor for OS. One patient from the sorafenib group and seven patients from the LD-CCRT group underwent curative surgical treatment. Patients who underwent surgical treatment had significantly longer OS. In conclusion, LD-CCRT showed superior survival outcomes to sorafenib in HCC patients with PVTT. LD-CCRT needs further consideration for its substantial local tumor control that can enable curative surgical treatment in selected patients.

Screening of Prognostic Biomarkers for Stereotactic Body Radiation Therapy in Primary Liver Cancer

Objective

So far there are still no effective immediate-early markers for assessing the efficacy of Stereotactic Body Radiation Therapy (SBRT). To find effective biomarkers for accurate assessment of the efficacy of SBRT in patients with primary liver cancer, we conducted this study including retrospective part and prospective part.

Material and Methods

589 patients with primary liver cancer were included at Ruikang Hospital affiliated to Guangxi Medical University from January 2012 to December 2018. Follow-up was conducted, clinical information and a total of 17 patients with 51 blood samples (before SBRT, before discharge and 2 months after SBRT) were collected. mRNAs profiles on 2 patients with 6 blood samples were detected by high-throughput sequencing, followed by qPCR verification on 15 patients with 45 blood samples.

Results

The commonly used serum biomarkers such as AFP, CEA, and CA125 shown low prognostic value in distinguishing survival group and death group, indicated by low AUC (less than .7) and Youden indexes (less than .5). Based on high-throughput sequencing of test group and qPCR detection of another verification group, we found 16 up-regulated and 12 downregulated genes after SBRT. Among them, ADIPOR1 and EPB42 showed significantly different between effective and ineffective group after SBRT, ROC suggested that based on the optimal threshold of .5838, ADIPOR1 shown a sensitivity of 100% and a specificity of 83.33% to distinguish effective from ineffective group. And EPB42 had a sensitivity of 75% and a specificity of 100% at the optimal threshold of 1.3817. In addition, GSEA showed that high expression of ADIPOR1 was mainly related to Mismatch repair, Circadian rhythm, Protein processing in endoplasmic reticulum, DNA replication, and Fanconi anemia pathways.

Conclusion

ADIPOR1 in whole blood is a promising candidate to act as prognostic biomarker for predication of SBRT outcomes in primary liver cancer patients.

Does stereotactic body radiation improve outcomes compared to conventional radiation for liver cancer patients?

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There has been a paradigm shift to SBRT without evidence that these high-dose ultra-low fractions result in improved outcomes.

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This prospective cohort compares the survival of patients treated with conventional versus SBRT treatments for liver tumours.

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The SBRT group received an average of 5 fractions, and the conventional group received an average of 17 fractions.

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397 patients were included. Overall survival was higher for SBRT patients at the 2-year time point (42% vs 27% p = 0.01).

Introduction

Methods

Results

Conclusion

Proton Beam Therapy in Managing Unresectable Hepatocellular Carcinoma with Bile Duct Invasion

Hepatocellular carcinoma (HCC) with bile duct invasion is a rare and notorious subtype of HCC. This study included patients that had unresectable HCC with bile duct invasion and proton beam therapy between November 2015 and February 2021. Twenty patients fit the inclusion criteria. The median tumor size was 6.3 cm. Nine patients (45.0%) had major vascular invasions. All included patients received the radiation dose of 72.6 gray relative biological effectiveness due to the proximity of porta hepatis and tumor. The median follow-up time was 19.9 months. The median overall survival was 19.9 months among deceased patients. The 1-year cumulative local recurrence rates were 5.3%, with only two patients developing in-field failure. The 1-year and 2-year overall survival rates were 79.4% and 53.3%. The 1-year progression-free survival was 58.9%. Four patients developed radiation-induced liver disease. The 1-year cholangitis-free survival was 55.0%. Skin toxicity was the most common acute toxicity and rarely severe. Eight patients developed ≤ grade 3 gastrointestinal ulcers. Proton beam therapy offers desirable survival outcomes for unresectable HCC patients with bile duct invasion. Optimal local tumor control could also be obtained within acceptable toxicities.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Phase 2 Study of Adjuvant Radiotherapy Following Narrow-Margin Hepatectomy in Patients With HCC

BACKGROUND AND AIMS

Surgical resection is the primary treatment for HCC; however, it is associated with a high rate of recurrence and death. We conducted this phase 2 study to investigate the efficacy and safety of postoperative intensity-modulated radiotherapy (IMRT) for HCC after narrow-margin hepatectomy.

APPROACH AND RESULTS

We designed a single-arm, prospective phase 2 trial to evaluate overall survival (OS), disease-free survival (DFS), recurrence patterns, and toxicity in patients receiving adjuvant radiotherapy. The eligibility criteria included the following: pathological diagnosis of HCC after hepatectomy, with narrow pathological margins (< 1 cm); age > 18 years; and Eastern Cooperative Oncology Group performance status score of 0 or 1. Patients received IMRT within 4-6 weeks after surgical resection. This trial was registered at ClinicalTrials.gov (NCT01456156). Between 2008 and 2016, a total of 76 eligible patients who underwent narrow-margin resection were enrolled. The median follow-up duration was 70 months; the 3-year OS and DFS rates were 88.2% and 68.1%, respectively; and the 5-year OS and DFS rates were 72.2% and 51.6%, respectively. Intrahepatic recurrence was the primary recurrence pattern. No marginal recurrence was found. Intrahepatic, extrahepatic, and combined recurrences at the first relapse were found in 33, 5, and 1 patient, respectively. The most common radiation-related grade-3 toxicities were leukopenia (7.9%), elevated alanine aminotransferase (3.9%) and aspartate aminotransferase (2.6%) levels, and thrombocytopenia (1.3%). Classical or nonclassical radiation-induced liver disease was not noted.

CONCLUSIONS

Adjuvant radiotherapy is an effective, well-tolerated, and promising adjuvant regimen in patients with HCC who have undergone narrow-margin hepatectomy. Our trial provides evidence and a rationale for planning a future phase 3 trial.

The Progress in the Treatment of Hepatocellular Carcinoma With Portal Vein Tumor Thrombus

Hepatocellular carcinoma (HCC) is one of most prevalent cancer and is a serious healthcare issue worldwide. Portal vein tumor thrombus (PVTT) is a frequent complication and remains as the blockage in the treatment of HCC with high recurrence rate and poor prognosis. There is still no global consensus or standard guideline on the management of HCC with PVTT. In western countries, Sorafenib and Lenvatinib are recommended as the first-line treatment options for HCC patients with PVTT where this condition is now regarded as BCLC Stage C regardless of PVTT types. However, there is growing evidence that supports the close relationship of the extent of PVTT to the prognosis of HCC. Besides the targeted therapy, more aggressive treatment modalities have been proposed and practiced in the clinic which may improve the prognosis of HCC patients with PVTT and prolong the patients’ survival time, such as transarterial chemoembolization, radiotherapy, hepatic resection, liver transplantation, and various combination therapies. Herein, we aim to review and summarize the advances in the treatment of HCC with PVTT.

Treatment for hepatocellular carcinoma with tumor thrombosis in the hepatic vein or inferior vena cava: A comprehensive review

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with a high mortality rate worldwide. The percentage of HCC patients with vascular invasion is high. However, tumor thrombus in the hepatic vein (HVTT) has a lower incidence than tumor thrombus in the portal vein (PVTT). Conventionally, HCC patients with HVTT are treated the same as HCC patients with PVTT and offered sorafenib or other systemic agents. However, according to recent studies, it is evident that HCC with HVTT shows different outcomes when classified into different subgroups. In this review, we discuss the recent progress and changes in treatment of HCC with HVTT.

Dose distribution effects of spot-scanning proton beam therapy equipped with a multi-leaf collimator for pediatric brain tumors

The present study simulated the effect of spot-scanning proton beam therapy (PBT) performed using a device equipped with a multi-leaf collimator (MLC) to calculate the dose distribution. Simulation studies using 18 pediatric patients with brain tumors in the posterior fossa were performed. Treatment plans were created for the MLC at different stages: Fully open (initial plan), fully closed to allow an irradiated area extending to 15 mm from the clinical target volume (CTV) (15-mm plan), or closing only the leaves where an organ at risk (OAR) overlapped with a border at 10 or 5 mm from the CTV (10- and 5-mm plans, respectively). The mean dose values for the brainstem, cervical cord, brain and cochlea in all MLC closure plans decreased as the MLC was closed (P=9.9×10⁻¹⁰, P=1.3×10⁻¹⁷, P=2.1×10⁻¹⁶ and P=2.0×10⁻⁵, respectively). The maximum dose (D_max) values of the cervical cord and cochlea in all MLC closure plans were also decreased as the MLC was closed (P=3.0×10⁻⁴ and P=1.1×10⁻⁵, respectively). The dose to the CTV was almost unchanged. In 10 patients, the D_max of the brain in all MLC-closure plans was higher than that of the initial plan, but the maximum increase was only 0.8 gray relative biological effectiveness [Gy(RBE)]. In conclusion, the existing MLC installed in the treatment device can be used to decrease the OAR dose significantly using spot-scanning PBT without a large capital investment. The dose from the scattered particles was small.

Single-cell RNA sequencing reveals the mechanism of sonodynamic therapy combined with a RAS inhibitor in the setting of hepatocellular carcinoma

BACKGROUND

Ras activation is a frequent event in hepatocellular carcinoma (HCC). Combining a RAS inhibitor with traditional clinical therapeutics might be hampered by a variety of side effects, thus hindering further clinical translation. Herein, we report on integrating an IR820 nanocapsule-augmented sonodynamic therapy (SDT) with the RAS inhibitor farnesyl-thiosalicylic acid (FTS). Using cellular and tumor models, we demonstrate that combined nanocapsule-augmented SDT with FTS induces an anti-tumor effect, which not only inhibits tumor progression, and enables fluorescence imaging. To dissect the mechanism of a combined tumoricidal therapeutic strategy, we investigated the scRNA-seq transcriptional profiles of an HCC xenograft following treatment.

RESULTS

Integrative single-cell analysis identified several clusters that defined many corresponding differentially expressed genes, which provided a global view of cellular heterogeneity in HCC after combined SDT/FTS treatment. We conclude that the combination treatment suppressed HCC, and did so by inhibiting endothelial cells and a modulated immunity. Moreover, hepatic stellate secretes hepatocyte growth factor, which plays a key role in treating SDT combined FTS. By contrast, enrichment analysis estimated the functional roles of differentially expressed genes. The Gene Ontology terms "cadherin binding" and "cell adhesion molecule binding" and KEGG pathway "pathway in cancer" were significantly enriched by differentially expressed genes after combined SDT/FTS therapy.

CONCLUSIONS

Thus, some undefined mechanisms were revealed by scRNA-seq analysis. This report provides a novel proof-of-concept for combinatorial HCC-targeted therapeutics that is based on a non-invasive anti-tumor therapeutic strategy and a RAS inhibitor.

Comparison of the [18F]-FDG and [18F]-FLT PET Tracers in the Evaluation of the Preclinical Proton Therapy Response in Hepatocellular Carcinoma

PURPOSE

The main objective of the present study was to compare the 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]-FDG) and 3'-[¹⁸F]fluoro-3'-deoxythymidine ([¹⁸F]-FLT) PET imaging biomarkers for the longitudinal follow-up of small animal proton therapy studies in the context of hepatocellular carcinoma (HCC).

PROCEDURES

SK-HEP-1 cells were injected into NMRI nude mice to mimic human HCC. The behavior of [¹⁸F]-FDG and [¹⁸F]-FLT tumor uptake was evaluated after proton therapy procedures. The proton single-fraction doses were 5, 10, and 20 Gy, with a dose rate of 10 Gy/min. The experimental protocol consisted of 8 groups of 10 mice, each group experiencing a particular dose/radiotracer condition. A reference PET exam was performed on each mouse the day before the irradiation procedure, followed by PET exams every 3 days up to 16 days after irradiation.

RESULTS

[¹⁸F]-FDG uptake showed a linear dose-dependent increase in the first days after treatment (37%, p < 0.05), while [¹⁸F]-FLT uptake decreased in a dose-dependent manner (e.g., 21% for 5 Gy compared to 10 Gy, p = 1.1e-2). At the later time point, [¹⁸F]-FDG normalized activity showed an 85% decrease (p < 0.01) for both 10 and 20 Gy doses and no variation for 5 Gy. Conversely, a significant 61% (p = 0.002) increase was observed for [¹⁸F]-FLT normalized activity at 5 Gy and no variation for higher doses.

CONCLUSION

We showed that the use of the [¹⁸F]-FDG and [¹⁸F]-FLT radiolabeled molecules can provide useful and complementary information for longitudinal follow-up of small animal proton therapy studies in the context of HCC. [¹⁸F]-FDG PET imaging enables a treatment monitoring several days/weeks postirradiation. On the other hand, [¹⁸F]-FLT could represent a good candidate to monitor the treatment few days postirradiation, in the context of hypo-fractioned and close irradiation planning. This opens new perspectives in terms of treatment efficacy verification depending on the irradiation scheme.

Downregulation of Mcl-1 by Panobinostat Potentiates Proton Beam Therapy in Hepatocellular Carcinoma Cells

Epigenetic modulation by histone deacetylase (HDAC) inhibitors is an attractive anti-cancer strategy for diverse hematological and solid cancers. Herein, we explored the relative effectiveness of the pan-HDAC inhibitor panobinostat in combination with proton over X-ray irradiation in HCC cells. Clonogenic survival assays revealed that radiosensitization of Huh7 and Hep3B cells by panobinostat was more evident when combined with protons than X-rays. Panobinostat increased G2/M arrest and production of intracellular reactive oxygen species, which was further enhanced by proton irradiation. Immunofluorescence staining of γH2AX showed that panobinostat enhanced proton-induced DNA damage. Panobinostat dose-dependently decreased expression of an anti-apoptotic protein, Mcl-1, concomitant with increasing acetylation of histone H4. The combination of panobinostat with proton irradiation enhanced apoptotic cell death to a greater extent than that with X-ray irradiation. Depletion of Mcl-1 by RNA interference enhanced proton-induced apoptosis and proton radiosensitization, suggesting a potential role of Mcl-1 in determining proton sensitivity. Together, our findings suggest that panobinostat may be a promising combination agent for proton beam therapy in HCC treatment.

Effect of radiotherapy on survival in advanced hepatocellular carcinoma patients treated with sorafenib: a nationwide cancer-registry-based study

Sorafenib is the standard treatment for advanced hepatocellular carcinoma (HCC) patients. This study aims to determine whether combining radiotherapy with sorafenib administration increases its efficacy. The study cohort included 4763 patients with diagnosed advanced HCC who received sorafenib between January 2012 and December 2015, as reported in medical records in the Taiwan Cancer Registry database. The effect of sorafenib with or without radiotherapy on survival was calculated using the Kaplan–Meier method and compared using the log-rank test. A Cox proportional hazards model was used for multivariate analysis. Patients receiving sorafenib plus radiotherapy had greater 1-year survival than did those receiving sorafenib alone (P < 0.001). Uni- and multivariate analyses also showed that radiotherapy increased survival after adjusting for confounders (adjusted HR 0.57; 95% CI 0.51–0.63). Further stratified analysis according to the timing of radiotherapy relative to sorafenib treatment revealed that patients who underwent radiotherapy after sorafenib had greater 1-year survival than did those undergoing radiotherapy within sorafenib use or sorafenib alone (adjusted HR 0.39; 95% CI 0.27–0.54). Combined treatment with sorafenib and radiotherapy results in greater HCC patient survival and should be considered an option for treating this challenging disease.

Clinical efficacy of external beam radiotherapy complementing incomplete transarterial chemoembolization for hepatocellular carcinoma

PURPOSE

External beam radiotherapy (EBRT) has been commonly applied as salvage or a combination locoregional modality after transarterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). This study reports oncologic outcomes and feasibility after application of the two modalities in our center.

METHODS

Forty consecutive patients who underwent EBRT due to incomplete responses of TACE were evaluated. Fourteen patients (35.0%) received stereotactic body radiotherapy (SBRT) and the remaining patients received conventionally fractionated radiotherapy (RT). A majority of patients who underwent SBRT received doses of 27 to 48 Gy in 3-4 fractions [median EQD₂ (Equivalent dose in 2 Gy per fraction radiotherapy): 57.0 Gy]. Conventionally fractionated RT was performed with a median EQD₂ of 47.8 Gy.

RESULTS

The median follow-up duration was 14.4 months (range: 2.6-83.0 months). A majority (77.5%) of patients were regarded as having Child-Pugh grade A. The median tumor size was 3.4 cm (range: 0.8-20.1 cm). Ten patients (25.0%) had thrombosis at a main portal branch. The 1- and 2-year overall survival (OS) and progression-free survival (PFS) rates were 82.2% and 42.1% and 55.8% and 32.1%, respectively. The local control rates were 89.1% and 89.1% at 1 and 2 years, respectively. The albumin level was a significant factor affecting OS (p = .002), and the BCLC stage significantly affected PFS (p = .001). Intrahepatic, out-of-field recurrence was the main cause of disease progression (60.0%), and distant metastasis developed in 12 patients (30.0%) during follow-up. Non-classic radiation-induced liver disease was seen in five (12.5%) patients, and two (5%) patients experienced grade ≥3 hepatic toxicities.

CONCLUSIONS

EBRT after incomplete TACE was feasible and yielded favorable oncologic outcomes. However, disease progression related to intrahepatic failure remained a hindrance.

Comparison of feature selection in radiomics for the prediction of overall survival after radiotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth more frequent cancer worldwide. This type of cancer has a poor overall survival rate mainly due to underlying cirrhosis and risk of recurrence outside the treated lesion. Quantitative imaging within a radiomics workflow may help assessing the probability of survival and potentially may allow tailoring personalized treatments. In radiomics a large amount of features can be extracted, which may be correlated across a population and very often can be surrogates of the same physiopathology. This issues are more pronounced and difficult to tackle with imbalanced data. Feature selection strategies are therefore required to extract the most informative with the increased predictive capabilities. In this paper, we compared different unsupervised and supervised strategies for feature selection in presence of imbalanced data and optimize them within a machine learning framework. Multi-parametric Magnetic Resonance Images from 81 individuals (19 deceased) treated with stereotactic body radiation therapy (SBRT) for inoperable (HCC) were analyzed. Pre-selection of a reduced set of features based on Affinity Propagation clustering (non supervised) achieved a significant improvement in AUC compared to other approaches with and without feature pre-selection. By including the synthetic minority over-sampling technique (SMOTE) for imbalanced data and Random Forest classification this workflow emerges as an appealing feature selection strategy for survival prediction within radiomics studies.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Elevated PDK1 Expression Drives PI3K/AKT/MTOR Signaling Promotes Radiation-Resistant and Dedifferentiated Phenotype of Hepatocellular Carcinoma

Resistance to radiotherapy (IR), with consequent disease recurrence, continues to limit the efficacy of contemporary anticancer treatment for patients with hepatocellular carcinoma (HCC), especially in late stage. Despite accruing evidence implicating the PI3K/AKT signaling pathway in cancer-promoting hypoxia, cancerous cell proliferation and radiotherapy-resistance, it remains unclear which molecular constituent of the pathway facilitates adaptation of aggressive HCC cells to tumoral stress signals and drives their evasion of repeated IR-toxicity. This present study investigated the role of PDK1 signaling in IR-resistance, enhanced DNA damage repair and post-IR relapse, characteristic of aggressive HCC cells, while exploring potential PDK1-targetability to improve radiosensitivity. The study employed bioinformatics analyses of gene expression profile and functional protein–protein interaction, generation of IR-resistant clones, flow cytometry-based ALDH activity and side-population (SP) characterization, siRNA-mediated loss-of-PDK1function, western-blotting, immunohistochemistry and functional assays including cell viability, migration, invasion, clonogenicity and tumorsphere formation assays. We showed that the aberrantly expressed PDK1 characterizes poorly differentiated HCC CVCL_7955, Mahlavu, SK-HEP1 and Hep3B cells, compared to the well-differentiated Huh7 or normal adult liver epithelial THLE-2 cells, and independently activates the PI3K/AKT/mTOR signaling. Molecular ablation of PDK1 function enhanced susceptibility of HCC cells to IR and was associated with deactivated PI3K/AKT/mTOR signaling. Additionally, PDK1-driven IR-resistance positively correlated with activated PI3K signaling, enhanced HCC cell motility and invasiveness, augmented EMT, upregulated stemness markers ALDH1A1, PROM1, SOX2, KLF4 and POU5F1, increased tumorsphere-formation efficiency and suppressed biomarkers of DNA damage—RAD50, MSH3, MLH3 and ERCC2. Furthermore, the acquired IR-resistant phenotype of Huh7 cells was strongly associated with significantly increased ALDH activity, SP-enrichment, and direct ALDH1-PDK1 interaction. Moreover, BX795-mediated pharmacological inhibition of PDK1 synergistically enhances the radiosensitivity of erstwhile resistant cells, increased Bax/Bcl-2 apoptotic ratio, while suppressing oncogenicity and clonogenicity. We provide preclinical evidence implicating PDK1 as an active driver of IR-resistance by activation of the PI3K/AKT/mTOR signaling, up-modulation of cancer stemness signaling and suppression of DNA damage, thus, projecting PDK1-targeting as a putative enhancer of radiosensitivity and a potential new therapeutic approach for patients with IR-resistant HCC.

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.

Clinical outcomes of previously untreated patients with unresectable intrahepatic cholangiocarcinoma following proton beam therapy

BACKGROUND

The effectiveness of proton beam therapy (PBT) as initial treatment for patients with unresectable intrahepatic cholangiocarcinoma (ICC) is unclear, particularly as related to ICC histological subtypes. We performed this study to address this gap in knowledge.

METHODS

Thirty-seven patients with unresectable ICC who underwent PBT as their initial treatment were evaluated. Twenty-seven patients had Child-Pugh class A liver function, 11 exhibited jaundice, and 10 had multiple tumors. Nineteen, 7, and 11 tumors were classified as mass forming (MF), periductal infiltrating (PI), and intraductal growth (IG) types, respectively, based on gross appearance in imaging studies. Patients were classified into the curative group (n = 25) and palliative group (n = 12) depending on whether the planning target volume covered all the macroscopic tumors.

RESULTS

The 1- and 2-year overall survival rates were 60.3, and 41.4%, respectively; the median survival time (MST) was 15 months for all patients. The MSTs for curative and palliative groups were 25 and 7 months, respectively. Curative treatment and adjuvant chemotherapy significantly improved overall survival, while the presence of periductal infiltrating type tumors was a negative prognostic factor. In the curative group, the 1- and 2-year local control rates were 100 and 71.5%, respectively, while the 1-, and 2-year progression-free survival rates were 58.5, and 37.6%, respectively. No severe acute toxicities were observed. Three patients experienced grade 3 biliary tract infection, although it was unclear whether this was radiotherapy-related.

CONCLUSION

PBT may yield to improve survival and local tumor control among patients with unresectable ICC.

Effectiveness of stereotactic ablative radiotherapy in patients with advanced hepatocellular carcinoma unsuitable for transarterial chemoembolization

Background:

Stereotactic ablative radiotherapy (SABR) can deliver tumoricidal doses and achieve long-term control in early hepatocellular carcinoma (HCC). However, limited studies have investigated the safety and effectiveness of SABR in patients with advanced diseases that is unsuitable for transarterial chemoembolization (TACE).

Methods:

In this observational study, we reviewed the medical records of patients with Barcelona Clinic Liver Cancer (BCLC) stage C disease treated with linear accelerator-based SABR between 2008 and 2016. Their tumors were either refractory to TACE or TACE was contraindicated. Overall survival (OS), in-field progression-free survival (IFPFS), and out-field progression-free survival were calculated using Kaplan–Meier analysis. The Cox regression model was used to examine the effects of variables. Treatment-related toxicities were scored according to the Common Terminology Criteria for Adverse Events (version 4.03) and whether patients developed radiation-induced liver disease (RILD) after SABR.

Results:

This study included 32 patients. The mean maximal tumor diameter and tumor volumes were 4.7 cm and 135.9 ml, respectively. Patients received linear accelerator-based SABR with a median prescribed dose of 48 Gy (30–60 Gy) in three to six fractions. Based on the assessment of treatment response by using the Response Evaluation Criteria in Solid Tumors (version 1.1), 19% of patients achieved a complete response and 53% achieved a partial response. After a median follow-up of 18.1 months (4.0–65.9 months), 10, 19, and 9 patients experienced in-field failure, out-field hepatic recurrence, and extrahepatic metastases, respectively. The estimated 2-year OS and IFPFS rates were 54.4% and 62.7%, respectively. In a multivariate analysis, a pretreatment Cancer of the Liver Italian Program (CLIP) score of ⩾2 (p = 0.01) was a prognostic factor for shorter OS, and a biologically effective dose (BED) of < 85 Gy₁₀ (p = 0.011) and a Child–Pugh score of ⩾6 (p = 0.014) were prognostic factors for inferior IFPFS. In this study five and eight patients developed classic and nonclassic RILD, respectively.

Conclusions:

SABR can serve as a salvage treatment for patients with HCC with BCLC stage C disease unsuitable for TACE, in particular, in those with a baseline CLIP score of ⩽1. A BED₁₀ of ⩾85 Gy is an appropriate prescribed dose for tumor control. Because out-field relapse is the major cause of treatment failure, SABR in combination with novel systemic modalities should be investigated in future studies.

The number of microspheres in Y90 radioembolization directly affects normal tissue radiation exposure

PURPOSE

In Y90 radioembolization, the number of microspheres infused varies by more than a factor of 20 over the shelf-life of the glass radioembolization device. We investigated the effect of the number of Y90 microspheres on normal liver tissue.

METHOD

Healthy pigs received lobar radioembolization with glass Y90 microspheres at 4, 8, 12, and 16 days post-calibration, representing a > 20× range in the number of microspheres deposited per milliliter in tissue. Animals were survived for 1-month post-treatment and the livers were explanted and scanned on a micro CT system to fully characterize the microscopic distribution of individual microspheres. A complete 3D microdosimetric evaluation of each liver was performed with a spatially correlated analysis of histopathologic effect.

RESULTS

Through whole-lobe microscopic identification of each microsphere, a consistent number of microspheres per sphere cluster was found at 4, 8, and 12 days postcalibration, despite an 8-fold increase in total microspheres infused from days 4 to 12. The additional microspheres instead resulted in more clusters formed and, therefore, a more homogeneous microscopic absorbed dose. The increased absorbed-dose homogeneity resulted in a greater volume fraction of the liver receiving a potentially toxic absorbed dose based on radiobiologic models. Histopathologic findings in the animals support a possible increase in normal liver toxicity in later treatments with more spheres (i.e., ≥ day 12) compared to early treatments with less spheres (i.e., ≤ day 8).

CONCLUSION

The microdosimetric evidence presented supports a recommendation of caution when treating large volumes (e.g., right lobe) using glass ⁹⁰Y microspheres at more than 8 days post-calibration, i.e., after "2nd week" Monday. The favorable normal tissue microscopic distribution and associated low toxicity of first week therapies may encourage opportunities for dose escalation with glass microspheres and could also be considered for patients with decreased hepatic reserve.

99m-Technetium galactosyl human serum albumin scanning to evaluate liver function after stereotactic body radiotherapy for hepatocellular carcinoma: A case report

The primary choice among treatment options for liver malignancies is surgery. However, if surgery cannot be performed, Stereotactic body radiotherapy (SBRT) may be effective. 99m-technetium galactosyl human serum albumin (GSA) single-photon emission computed tomography (SPECT) imaging is useful for the assessment of liver function before surgery. We report the case of a 77-year-old man who had undergone SBRT for hepatocellular carcinoma of the left lobe of the liver 2 years previously. Follow-up revealed a 15-mm hepatocellular carcinoma at the edge of the right lobe of the liver. 99m-technetium GSA SPECT was performed before SBRT to confirm that there was no accumulation in the left lobe and to ensure that there was good function of the right lobe. Three months after SBRT, the tumor had responded, and decreases in GSA accumulation were observed in line with the radiation beam. Because hepatocellular carcinoma often relapses, it is important to assess the anatomic site of liver dysfunction before and after radiation. This case demonstrates that 99m-technetium GSA SPECT is useful for this purpose.

Impact of Proton Beam Irradiation of an Anatomic Subsegment of the Liver for Hepatocellular Carcinoma

PURPOSE

The objective of this research was to elucidate the impact on the prognosis, including the survival prognosis, resulting from proton beam irradiation of an anatomic subsegment of the liver (ASPT) for the treatment of hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

A total of 110 patients who received a diagnosis of HCC were analyzed in this retrospective study. Definitive proton beam therapy was delivered at a dose of 76 Gy (relative biological effectiveness) in 20 fractions between January 2008 and December 2015. When the HCC widely abutted blood vessels or when multiple HCC tumors occurred within the same liver subsegment, the clinical target volume was outlined as an anatomic subsegment of the liver, according to the portal territory, containing the tumor. In the remaining cases, the clinical target volume was delineated by adding a 5-mm margin around the gross tumor volume. The overall survival (OS), progression-free survival (PFS), and local control rates and adverse events were assessed. A review of the medical charts assessed adverse events that occurred during and after the treatment and were classified according to the Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

The median follow-up duration was 36.5 months (range, 1-90.6 months). The median age of the patients was 73 years (range, 48-90 years). ASPT was performed in 31 patients (28%). Three-year OS, PFS, and local control rates were 74.2%, 40.4%, and 91.7%, respectively. Multivariate analysis identified ASPT as a factor that significantly improved PFS (P = .049) but not OS (P = .79). No association was found between ASPT and the frequency of grade ≥3 acute/late adverse events.

CONCLUSIONS

ASPT was associated with a reduction in the rate of tumor progression and no significant toxicity but was not associated with OS.

Proton beam therapy versus stereotactic body radiotherapy for hepatocellular carcinoma: practice patterns, outcomes, and the effect of biologically effective dose escalation

BACKGROUND

Stereotactic body radiation therapy (SBRT) and proton beam therapy (PBT) generally are safe and effective for non-operative hepatocellular carcinoma (HCC). To date, data comparing the two modalities are limited. We aimed to identify the practice patterns and outcomes of nonsurgical HCC cases treated definitively with either SBRT or PBT.

METHODS

We queried the National Cancer Database for T1-2N0 HCC patients receiving PBT or SBRT from 2004 to 2015. Patients were excluded for any treatment other than non-palliative external beam radiotherapy. A multivariable binomial regression model identified patterns of SBRT/PBT use, and propensity-matched multivariable Cox regression assessed correlates of survival.

RESULTS

A total of 71 patients received PBT and 918 patients received SBRT (median follow-up 45 months). SBRT was used in 1.8% of nonoperative early stage HCC cases in 2004 and 4.2% of cases in 2015, whereas PBT was used in 0.1-0.2% of cases every year. The median biologically effective dose (BED) for SBRT and PBT was 100 Gy10 and 98 Gy10, respectively (OR =0.70, P=0.17). Factors predictive of receiving PBT included: white race, higher comorbidity score, higher education, metropolitan residence, tumors >5 cm and recent treatment (all P<0.05). Both PBT (HR =0.48, 95% CI: 0.29-0.78) and BED ≥100 Gy10 (HR =0.61, 95% CI: 0.38-0.98) were independent predictors for longer survival.

CONCLUSIONS

Although not implying causation and requiring prospective corroboration, PBT was independently associated with longer survival than SBRT, despite being delivered to HCC patients with multiple poor prognostic factors. PBT may also allow for safer BED escalation, which also independently associated with outcomes.

Long-Term Results of High-Dose 2-Fraction Carbon Ion Radiation Therapy for Hepatocellular Carcinoma

Purpose

Carbon ion beams have several physical and biological advantages compared with conventional radiation for cancer therapy. The objective of this study is to evaluate the safety and effectiveness of 2-fraction carbon ion radiation therapy (CIRT) in patients with hepatocellular carcinoma (HCC).

Methods and Materials

Between December 2008 and March 2013, 57 patients with localized HCC were treated with CIRT at a total dose of 45 Gy (relative biological effectiveness) in 2 fractions and retrospectively analyzed after long-term observation. The main endpoints of this study were treatment-related toxicity and local tumor control. Toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. Changes in the Child-Pugh score from before to after CIRT were also examined to evaluate hepatic toxicity. Local control was defined as no progression of the irradiated lesion according to the modified Response Evaluation Criteria in Solid Tumors.

Results

The median age of the patients was 75 years (range, 49-89 years). Of these patients, 41 had a newly diagnosed lesion, and 16 had residual or recurrent lesions after previous treatments. The median follow-up duration was 54 months (range, 7-103 months). All surviving patients were followed for more than 51 months. Two patients experienced grade 3 acute skin reactions, but no other grade 3 or higher toxicities were observed in any organ. No patient exhibited an increase in the Child-Pugh score of 2 or more points after CIRT. The local tumor control rates at 1, 3, and 5 years were 98%, 91%, and 91% after CIRT, respectively. All lesions that failed to respond to previous treatments were successfully controlled by CIRT. The 1-, 3-, and 5-year overall survival rates were 97%, 67%, and 45%, respectively.

Conclusions

Two-fraction CIRT was a well-tolerated and effective treatment for patients with HCC.

Comparing treatment patterns of hepatocellular carcinoma at academic centers and non-academic centers within the Mountain Region

BACKGROUND

Our objective is to explore differences in survival and treatment approaches for hepatocellular carcinoma (HCC) between academic centers (ACs) and non-academic centers (NACs), which may contribute to disparities in the Mountain Region (MR).

METHODS

Using the National Cancer Database, HCC cases from 2004 to 2015 in the MR were divided into AC and NAC subgroups. Cox-proportional hazard regression and binary logistic regression were performed to analyze survival, compare treatment patterns, and examine the effect of facility type and surgical approach on margin status.

RESULTS

Treatment at ACs, compared to NACs, is associated with improved survival. At ACs, the odds of surgical or systemic treatment were higher. The odds of receiving radiation and positive margins was lower. Overall, the odds of positive margins was higher with laparoscopic compared to open or an unspecified surgical approach; this relationship persisted on subgroup analysis of NACs, but not ACs.

CONCLUSIONS

Treatment of HCC at an AC in the MR increases the odds of surgery and improves survival. A laparoscopic approach increases the odds of positive margins, irrespective of center type.

Recent clinical applications of external beam radiotherapy for hepatocellular carcinoma according to guidelines, major trials and meta-analyses

External beam radiotherapy (EBRT) for hepatocellular carcinoma (HCC) has not been widely used due to lack of high-level evidence, despite its potent local therapeutic effect. While clinical evidence has accumulated and meta-analyses of observational studies have provided integrated information to help in clinical decision-making, a recent randomized trial demonstrated the benefit of EBRT in cases of HCC with major vessel invasion. Based on these trends, the efficacy of EBRT has been better recognized, and EBRT has been more frequently recommended in several international treatment guidelines newly updated in 2018. This review examined the key issues of EBRT in the guidelines updated in 2018 as well as recently published noteworthy randomized trials and meta-analyses. Ongoing trials to identify the trends and direction of future research on EBRT for HCC were also reviewed.

Folic acid conjugated polymeric drug delivery vehicle for targeted cancer detection in hepatocellular carcinoma

Targeted therapies provide increased efficiency for the detection and treatment of cancer with reduced side effects. Folate receptor (alpha subunit) is overexpressed in multiple tumors including liver cancer. In this study, we evaluated the specificity and toxicity of a folic acid-containing drug delivery vehicle (DDV) in a hepatocellular carcinoma (HCC) model. The DDV was prepared with two units each of folic acid (FA) and fluorescein isothiocyanate (FITC) molecules and conjugated to a central poly (ethylene glycol) (PEG) core via a modified chemo-enzymatic synthetic process. Rat hepatoma (N1S1) and human monocytic (U937) cell lines were used for cell culture-based assays and tested for DDV uptake and toxicity. Folate receptor expressions in liver tissues and cell lines were verified using standard immunohistochemistry techniques. Rat HCC model was used for in vivo assessment. The DDV was injected via intra-arterial or intravenous methods and imaged with IVIS spectrum in vivo imaging system. Strong signals of FITC in the liver tumor region correlated to targeted DDV uptake. The use of PEG enhanced water-solubility and provided flexibility for the interaction of FA ligands with multiple cell surface folate receptors that resulted in increased specific uptake. Our study suggested that PEG incorporation and folate targeting via intra-arterial approach is an efficient strategy for targeted delivery in HCC therapy.

A nomogram to predict prognosis of patients with unresected hepatocellular carcinoma undergoing radiotherapy: a population-based study

Background: Radiotherapy is a primary treatment strategy for patients with unresectable hepatocellular carcinoma (HCC); however, the prognostic factors among HCC patients who have received radiotherapy but not undergone surgery have not been systematically studied. Thus, the prognostic factors were investigated in this study based on the Surveillance, Epidemiology, and End Results (SEER) Medicare database.

Methods: A screening process was used for select cases from the SEER database. Survival was analyzed using the Kaplan-Meier method and log-rank test, the Cox proportional hazards regression model, and a competing risk model. A nomogram was established for predicting 1- and 3-year overall survival (OS) of patients.

Results: A total of 1305 HCC patients who received radiotherapy but had not undergone surgery were included in this study and divided into training (n = 1175) and validation cohorts (n = 130). Patients in the training cohort had a 1-year OS rate of 30.9±1.3%, a 3-year OS rate of 10.0±1.0%, and a median survival rate of 6.0 months (range, 5.4-6.6 months). Race (p = 0.025), T stage (p < 0.001), N stage (p < 0.001), M stage (p < 0.001), and chemotherapy (p < 0.001) were identified as independent risk factors by multivariate analyses in the training cohort, while sex, age, grade, marital status, and insurance status were not independent factors. Survival in patients who received radiotherapy was worse with respect to the following characteristics: black race; higher T, N, or M stage; and no chemotherapy. A nomogram was established based on the results of the multivariate analysis, which was internally validated by a concordance index (C-index) of 0.731±0.016 and a group of calibration plots. External validation was carried out and the C-index was 0.738±0.049, which demonstrated the effectiveness of the nomogram we constructed.

Conclusions: Race, T stage, N stage, M stage, and chemotherapy were independent risk factors for survival of HCC patients who received radiotherapy but had not undergone surgery. A validated nomogram was formulated to predict 1- and 3-year OS in these patients based on individual clinical characteristics.

Targeting DNA-dependent protein kinase sensitizes hepatocellular carcinoma cells to proton beam irradiation through apoptosis induction

Recent studies have highlighted the implications of genetic variations in the relative biological effectiveness (RBE) of proton beam irradiation over conventional X-ray irradiation. Proton beam radiotherapy is a reasonable radiotherapy option for hepatocellular carcinoma (HCC), but the impact of genetic difference on the HCC RBE remains unknown. Here, we determined proton RBE in human HCC cells by exposing them to various doses of either 6-MV X-rays or 230-MeV proton beams. Clonogenic survival assay revealed variable radiosensitivity of human HCC cell lines with survival fraction at 2 Gy ranging from 0.38 to 0.83 and variable proton RBEs with 37% survival fraction ranging from 1.00 to 1.48. HCC cells appeared more sensitive to proton irradiation than X-rays, with more persistent activation of DNA damage repair proteins over time. Depletion of a DNA damage repair gene, DNA-PKcs, by siRNA dramatically increased the sensitivity of HCC cells to proton beams with a decrease in colony survival and an increase in apoptosis. Our findings suggest that there are large variations in proton RBE in HCC cells despite the use of a constant RBE of 1.1 in the clinic and targeting DNA-PKcs in combination with proton beam therapy may be a promising regimen for treating HCC.

Optimizing radiotherapy with immune checkpoint blockade in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer, and its incidence is rapidly increasing in North America and Western Europe as well as South-East Asia. Patients with advanced stage HCC have very poor outcomes; therefore, the discovery of new innovative approaches is urgently needed. Cancer immunotherapy has become a game-changer and revolutionized cancer treatment. A comprehensive understanding of tumor-immune interactions led to the development of immune checkpoint inhibitors (ICIs) as new therapeutic tools, which have been used with great success. Targeting immune checkpoint molecules such as programmed cell death-1 (PD-1) and cytotoxic T lymphocyte-associated protein-4 (CTLA-4) reinvigorates anti-tumor immunity by restoring exhausted T cells. Despite their effectiveness in several types of cancer, of the many immune suppressive mechanisms limit the efficacy of ICI monotherapy. Radiation therapy (RT) is an essential local treatment modality for a broad range of malignancies, and it is currently gaining extensive attention as a promising combination partner with ICIs because of its ability to trigger immunogenic cell death. The efficacy of combination approaches using RT and ICIs has been well documented in numerous preclinical and clinical studies on various types of cancers but not HCC. The application of ICIs has now expanded to HCC, and RT is recognized as a promising modality in HCC. This review will highlight the current roles of PD-1 and CTLA-4 therapies and their combination with RT in the treatment of cancers, including HCC. In addition, this review will discuss the future perspectives of the combination of ICIs and RT in HCC treatment.

Serum Levels of Hepatocyte Growth Factor and CD40 Ligand Predict Radiation-Induced Liver Injury

BACKGROUND: Declining liver function is a concerning side effect associated with radiation therapy. Biomarkers of liver toxicity would be useful in personalizing therapy. METHODS: As part of two prospective clinical trials examining adaptive radiation therapy, we collected serum samples from patients receiving liver radiation. We performed a screen of 22 cytokines using a multiplex assay then used ELISA to quantify the cytokines of greatest interest. Subjects were split into screening and validation cohorts. Toxicity was defined as an increase in Child-Pugh score of 2 points or greater within 6 months. Logistic regression models were used to estimate the relationship between our toxicity endpoint and serum cytokine concentrations. RESULTS: Our initial screen (46 subjects, 11 events) identified hepatocyte growth factor (HGF), CD40L (CD154), and eotaxin (CCL11) as potentially predictive of toxicity. We then tested these markers in an expanded patient cohort (104 subjects, 18 events) with a batch correction due to varying age of the samples which confirmed that high HGF and low CD40L were associated with a subsequent decline in liver function following radiation therapy. Multivariate analysis factoring in baseline Child-Pugh score and mean liver radiation dose demonstrated that HGF and CD40L were potentially predictive of toxicity (HGF OR 4.3, P = .009; CD40L OR 0.5 P = .06). Additionally, higher than median baseline HGF levels (1.4 ng/ml) were significantly associated with decreased survival following liver radiation (27.1 vs 14.5 months, P = .03). CONCLUSIONS: Our study identifies high HGF and low CD40L as potential markers of liver toxicity following radiation therapy.

Imaging post-stereotactic body radiation therapy responses for hepatocellular carcinoma: typical imaging patterns and pitfalls

Stereotactic body radiation therapy (SBRT) has increased utility in the management of hepatocellular carcinoma (HCC) ranging from local therapy in early-stage HCC not suitable for other focal therapies to end-stage HCC. As the indications for the use of SBRT in HCC expand, diagnostic imaging is being increasingly used to assess response to treatment. The imaging features of tumor response do not parallel those of other focal therapies such as radiofrequency ablation or trans-arterial chemoembolization that immediately devascularize the tumor. The tumor response to SBRT on imaging takes much longer and often shows gradual changes including the reduction of enhancement and size over several months. It is essential to recognize the typical imaging patterns of response, as well as the appearance of focal liver reaction in the non-target liver that can confound image interpretation. The timing of treatment response assessment imaging is fundamental to minimize the potential for false negative response. The purpose of this article is to review the variable post-SBRT imaging features of HCC and adjacent liver parenchyma and discuss the potential pitfalls of imaging evaluation after SBRT for HCC.

Radioprotective effects of mistletoe extract in zebrafish embryos in vivo

Introduction: Radioprotectors can enhance the efficacy of cancer radiotherapy, but their clinical use remains uncommon. The present study aimed to assess the radioprotective potential of mistletoe extract (commercial name: Abnoba Viscum), a well-known complementary cancer medicine, in zebrafish larvae. Materials and methods: Wild-type AB zebrafish embryos at 4 h-post-fertilization were exposed to 5 Gy 9-MeV electron beam irradiation after being treated for 1 h with 4 mMl/L amifostine or 0.2 mg/ml Abnoba Viscum A, F, M, or Q. Primary endpoints were abnormality-free survival and abnormality-free rates among survivors at 5 days-post-fertilization. Results: The crude abnormality-free survival rates were 33.7%, 49.0%, 38.8%, 43.9%, 38.1%, and 52.6%, whereas abnormality-free rates among survivors were 36.4%, 49.6%, 37.8%, 45.6%, 52.0%, and 62.8% for the control (with no pharmacologic treatment), amifostine, Abnoba Viscum A, F, M, and Q groups, respectively. Abnormality-free survival rates in the amifostine and Abnoba Viscum Q groups were significantly different from those in the control (p = .040 and .012, respectively), with an odds ratio (OR) of 1.90 [95% confidence interval (CI): 1.03-3.51] and 2.20 (95% CI: 1.19-4.08), respectively. Abnormality-free rates among survivors in the amifostine and Abnoba Viscum M and Q groups were significantly different from those in the control group (p = .048, .042, and <.001, respectively), with an OR of 1.79 (95% CI: 1.00-3.20), 1.82 (95% CI: 1.02-3.26), and 2.98 (1.67-5.33), respectively. Conclusion: Abnoba Viscum Q has at least a similar radioprotective effect to that of amifostine. Mistletoe extracts have been clinically applied for a long time and their effectiveness and feasibility have been verified. Abnoba Viscum Q might be a new candidate radioprotectant to enhance cancer radiotherapy efficacy.