An evaluation of hepatocellular carcinoma practice guidelines from a radiation oncology perspective

Tumor cell-intrinsic MELK enhanced CCL2-dependent immunosuppression to exacerbate hepatocarcinogenesis and confer resistance of HCC to radiotherapy

BACKGROUND

The outcome of hepatocellular carcinoma (HCC) is limited by its complex molecular characteristics and changeable tumor microenvironment (TME). Here we focused on elucidating the functional consequences of Maternal embryonic leucine zipper kinase (MELK) in the tumorigenesis, progression and metastasis of HCC, and exploring the effect of MELK on immune cell regulation in the TME, meanwhile clarifying the corresponding signaling networks.

METHODS

Bioinformatic analysis was used to validate the prognostic value of MELK for HCC. Murine xenograft assays and HCC lung metastasis mouse model confirmed the role of MELK in tumorigenesis and metastasis in HCC. Luciferase assays, RNA sequencing, immunopurification-mass spectrometry (IP-MS) and coimmunoprecipitation (CoIP) were applied to explore the upstream regulators, downstream essential molecules and corresponding mechanisms of MELK in HCC.

RESULTS

We confirmed MELK to be a reliable prognostic factor of HCC and identified MELK as an effective candidate in facilitating the tumorigenesis, progression, and metastasis of HCC; the effects of MELK depended on the targeted regulation of the upstream factor miR-505-3p and interaction with STAT3, which induced STAT3 phosphorylation and increased the expression of its target gene CCL2 in HCC. In addition, we confirmed that tumor cell-intrinsic MELK inhibition is beneficial in stimulating M1 macrophage polarization, hindering M2 macrophage polarization and inducing CD8 + T-cell recruitment, which are dependent on the alteration of CCL2 expression. Importantly, MELK inhibition amplified RT-related immune effects, thereby synergizing with RT to exert substantial antitumor effects. OTS167, an inhibitor of MELK, was also proven to effectively impair the growth and progression of HCC and exert a superior antitumor effect in combination with radiotherapy (RT).

CONCLUSIONS

Altogether, our findings highlight the functional role of MELK as a promising target in molecular therapy and in the combination of RT therapy to improve antitumor effect for HCC.

Managing vestibular schwannomas with radiosurgery and radiotherapy: AGREE II appraisal of clinical practice guidelines

INTRODUCTION

Vestibular schwannomas (VSs) are rare, benign intracranial tumours that have prompted clinical practice guideline (CPG) creation given their complex management. Our aim was to utilize the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument to assess if such CPGs on the management of VSs with radiosurgery and radiotherapy are of acceptable quality.

METHODS

Relevant CPGs were identified following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocols. Experienced reviewers then extracted general CPG properties and rated their quality via the AGREE II instrument. Intraclass correlation coefficients (ICCs) were quantified to assess interrater reliability.

RESULTS

Nine CPGs on the management of VSs with radiosurgery and radiotherapy were identified. All CPGs were created in the past six years and developed recommendations based on literature review and expert consensus. One guideline was deemed as high quality with seven others being moderate and one being low in quality. The clarity of the presentation domain had the highest mean scaled domain score of 96.0%. The domains of stakeholder involvement and applicability had the lowest means of 49.2% and 47.2%, respectively. ICCs were either good or excellent across all domains.

CONCLUSION

Current CPGs on the management of VSs with radiosurgery and radiotherapy are of acceptable quality but would greatly benefit from improvements in applicability, stakeholder involvement, editorial independence and rigour of development. We recommend CPG authors reference the European Association of Neuro-Oncology (EANO) guideline as a developmental framework with the Congress of Neurological Surgeons/American Association of Neurological Surgeons (CNS/AANS) CPG being a valid alternative.

Benefit of perioperative radiotherapy for hepatocellular carcinoma: a quality-based systematic review and meta-analysis

INTRODUCTION

Although surgery is the standard curative modality for hepatocellular carcinoma, more than two-thirds experience intrahepatic recurrence. Since no standard perioperative treatment has been established, the authors performed a meta-analysis to evaluate the benefits of perioperative radiotherapy (RT).

METHODS

The PubMed, MEDLINE, EMBASE, and Cochrane Library were searched until May 2023. Randomized or propensity-matched studies evaluating at least five major clinical factors investigating benefit of perioperative RT, were included. The main effect measure were the pooled odds ratios (OR) regarding the benefit of perioperative RT using 2-year overall survival (OS) and 1-year disease-free survival (DFS) data.

RESULTS

Seven studies (five randomized and two propensity-matched studies) involving 815 patients were included. The pooled ORs for 1-year DFS and 2-year OS were 0.359 (95% CI: 0.246-0.523) and 0.371 (95% CI: 0.293-0.576), respectively, favoring perioperative RT, with very low heterogeneity. In the subgroup analyses, the benefits of OS and DFS were consistent between the two subgroups [portal vein thrombosis (PVT) and narrow resection margin (RM) groups]. In the PVT subgroup, the pooled OS rates at both 1-year and 2-year (75.6 vs. 36.9%, P <0.001; 25.6 vs. 9.9%, P =0.004) and DFS rates at both 1-year and 2-year (25.2 vs. 10.3%, P =0.194; 11.9 vs. 3.0%, P =0.022) were higher in the perioperative RT group. In the narrow RM subgroup, the surgery and RT groups showed higher pooled OS rates for both 1-year and 2-year (97.3 vs. 91.9%, P =0.042; 90.4 vs. 78.7%, P =0.051) and DFS (88.1 vs. 72.6%, P <0.001; 70.1 vs. 51.7%, P <0.001). Grade 5 toxicity was not reported, and three studies reported grade ≥3 or higher liver function test abnormalities, ranging from 4.8-19.2%.

CONCLUSION

The present study supports the oncological benefits of perioperative RT, for cases with high-risk of recurrence. Oncologic outcomes between subgroups differed according to clinical indications.

BMI1 Silencing Liposomes Suppress Postradiotherapy Cancer Stemness against Radioresistant Hepatocellular Carcinoma

Radiotherapy causes DNA damage by direct ionization and indirect generation of reactive oxygen species (ROS) thereby destroying cancer cells. However, ionizing radiation (IR) unexpectedly elicits metastasis and invasion of cancer cells by inducing cancer stem cells' (CSCs) properties. As BMI1 is a crucial gene that causes radioresistance and an unfavorable prognosis of hepatocellular carcinoma (HCC), BMI1 inhibitor PTC-209 has been encapsulated in a ROS-responsive liposome (LP(PTC-209)) to be temporally and spatially delivered to radioresistant HCC tissue. The ROS generated during IR was not only considered to directly cause tumor cell death but also be used as a stimulator to trigger ROS-responsive drug release from LP(PTC-209). The PTC-209 released into resistant HCC tissue under radiotherapy further led to cancer stem cell (CSC) differentiation and then recovered radiosensitivity of HCC tumor. The suppression of the radioresistant performance of LP(PTC-209) has been proved on radiosensitive and radioresistant Hepa1-6 CSC tumor models, respectively. Our study clarified the relationship between radiotherapy and cancer stemness and provided insights to achieve complete suppression of radioresistant HCC tumor by inhibiting cancer stemness.

miR-146a-5p Alleviates Radiation-Induced Liver Fibrosis by Regulating PTPRA-SRC Signaling in Mice

Patients with hepatobiliary tumors who accept radiotherapy are at risk for radiation-induced liver fibrosis. MicroRNAs (miRNAs) have been implicated in the pathogenesis of radiation-induced liver damage and possess potential as novel biomarkers and therapeutic targets. However, the role of miR-146a-5p in radiation-induced liver fibrosis is less well understood. The current study was designed to evaluate the role of miR-146a-5p in radiation-induced liver fibrosis in mice and to investigate the possible mechanisms involved in miR-146a-5p-mediated effects. The experiments were performed on Institute of Cancer Research (ICR) mice which received fractionated radiation (30 Gy in 5 fractions) to the liver. The results show radiation could induce histopathological changes, liver dysfunction and fibrosis accompanied with decreased miR-146a-5p expression. miR-146a-5p agomir treatment resulted in recovery of liver function and reduced the amount of alpha-smooth muscle actin (α-SMA), collagen 1, protein tyrosine phosphatase receptor type A (PTPRA) and phosphorylated SRC in the livers of irradiated mice. Therefore, our study reveals that miR-146a-5p inhibits the progression of hepatic fibrosis after radiation treatment. And the beneficial role of miR-146a-5p may be relevant to PTPRA-SRC signaling pathway.

Association between Posttreatment Serum Platelet-to-Lymphocyte Ratio and Distant Metastases in Patients with Hepatocellular Carcinoma Receiving Curative Radiation Therapy

Background: We sought to investigate whether serum immune and inflammatory parameters can help to predict distant metastasis (DM) in patients with unresectable hepatocellular carcinoma (HCC) undergoing curative radiation therapy (RT). Methods: A total of 76 RT courses were analyzed. The following variables were included in the analysis: systemic inflammation index, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), prognostic nutritional index (PNI), absolute lymphocyte count, lymphocyte-to-monocyte ratio, albumin, albumin-to-alkaline phosphatase ratio, RT-related parameters, and levels of total protein, hemoglobin, α-fetoprotein, and PIVKA-II. Distant control (DC) and overall survival (OS) rates were calculated and compared. Results: The mean age was 61.4 years, and most patients were men (n = 62, 81.6%). The median RT fraction number and fractional doses were 12 (range, 4–30) and 5 (range, 2–12) Gy, respectively. With a median follow-up of 12 (range, 3.1–56.7) months, the 1-year DC and OS rates were 64.4% and 55.2%, respectively. The development of DM significantly deteriorated OS (p = 0.013). In the multivariate analysis, significant independent prognostic indicators for DC and OS rates were the highest posttreatment PLR (≤235.7 vs. >235.7, p = 0.006) and the lowest posttreatment PNI (≤25.4 vs. >25.4, p < 0.001), respectively. Conclusions: Posttreatment serum PLR might be helpfully used as a predictive biomarker of DM in unresectable HCC patients undergoing RT. Future research is necessary to confirm our findings.

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.

Clinical care in hepatocellular carcinoma: A mixed methods assessment of experiences and challenges of oncology professionals

INTRODUCTION

Healthcare providers (HCPs) may face numerous dilemmas in optimally screening, diagnosing, and treating patients with, and/or at risk for, hepatocellular carcinoma (HCC). This study aimed to achieve a greater understanding of the challenges in HCC care which in turn could delineate HCP educational opportunities within this oncologic sub-specialty.

METHODS

A mixed-methods approach was used to identify practice gaps and clinical barriers experienced by US-based medical oncologists, hepatologists, oncology physician assistants, oncology nurse practitioners, and interventional radiologists involved in HCC care. The qualitative (semi-structured interview) and quantitative (survey) data collection approaches were deployed sequentially with findings subsequently triangulated.

RESULTS

A total of 214 HCPs participated in this study. Analysis revealed challenges related to screening and diagnosing HCC, specifically in applying appropriate screening guidelines, and the optimal use and decisions related to diagnostic imaging and biopsy. Issues related to treatment selection included the application of existing HCC guidelines in treatment decision-making, weighing risk/benefit ratios of various antineoplastics regimens (i.e., tyrosine kinase inhibitors-TKIs, immunotherapy agents, chemotherapy), sequencing therapies, potential toxicity management, and optimally educating patients about their HCC.

CONCLUSION

These findings highlight the educational needs of those involved in HCC care and provide a starting point for clinicians to both reflect on their practice and identify opportunities to enhance communication within the HCC team and between provider and patient. There is an opportunity to optimize continuing professional development interventions that address the identified gaps in clinical practice specifically related to teamwork and interdisciplinary communication.

Evaluation of the Clinical Efficacy of Intensity-Modulated Radiotherapy Combined with Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma with Extrahepatic Oligometastasis and Prognostic Factors for Patient Survival

Objective

To investigate the clinical efficacy of intensity-modulated radiotherapy (IMRT) combined with transcatheter arterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) patients with extrahepatic oligometastasis and the prognosis of patients receiving this treatment.

Patients and Methods

Twenty-one HCC patients with extrahepatic oligometastasis were retrospectively analyzed; seven patients received IMRT only, and 14 received IMRT plus TACE. TACE treatment was administered before IMRT (50 mg epirubicin, oxaliplatin 100 mg, and mitomycin 10 mg). The short-term efficacy of this treatment and patient prognosis were evaluated.

Results

Complete response (CR) and partial response (PR) in the intrahepatic region were achieved in three and 14 patients, respectively. The objective response rate (ORR) approached 81%. CR and PR were achieved in six and 10 patients with extrahepatic metastases, respectively, for an ORR of 100%. Pain was completely relieved in all patients with bone metastases. The median overall survival (OS) and progression-free survival (PFS) were 21 months and 9.1 months, respectively. The 1-year PFS rate was 43%, and the 1-, 2-, 3-, and 4-year OS rates were 83%, 35%, 9%, and 4%, respectively. Univariate analysis showed that the prognostic factors for patient survival included Child-Pugh class, vascular thrombus, Karnofsky performance status (KPS), radiotherapy dose, ascites, combination therapy, and pattern of progression. Multivariate analysis showed that vascular thrombus, combination therapy, and pattern of failure were prognostic factors for PFS, and the KPS was the only prognostic factor for OS. No grade 3-4 adverse reactions were observed.

Conclusion

IMRT combined with TACE is safe and feasible without major toxicities for the treatment of advanced HCC patients with extrahepatic oligometastasis and results in excellent objective efficacy and a potential survival benefit. The KPS is the only predictive factor for OS. This approach is expected to be a useful palliative option for selected HCC patients with extrahepatic metastases.

Radiotherapy for bone metastases of hepatocellular carcinoma: a hybrid systematic review with meta-analyses

INTRODUCTION

External beam radiation therapy (EBRT) is commonly used as a palliative treatment for bone metastases of hepatocellular carcinoma (HCC). We planned a hybrid systematic review that meta-analyzed the efficacy and feasibility of EBRT and reviewed the literature to answer specific clinical questions.

METHODS

The PubMed, Medline, Embase, and Cochrane Library databases were searched through 1 December 2021. Primary endpoints were overall survival (OS) and response rate (RR). Secondary endpoints were comparative data, including treatment response and survival related to dose escalation, number of metastases, and fractionation scheme. Formal pooled analyses were performed on the primary endpoints, and the secondary endpoints were systematically reviewed. Complications were also reviewed.

RESULTS

Nineteen studies involving 1613 patients with HCC and bone metastases were included. The median OS was 6 months (range: 3-13 months). The pooled one-year OS was 23.1% (95% confidence interval [CI]: 18.4-28.6); pooled pain RR was 81.5% (95% CI: 76.4-85.7) and of pain complete remission was 26.5% (95% CI: 21.7-32.0). Pain response might be related to dose escalation, considering the moderate consistency of results and plausibility, with a low-quality grade of evidence^†. Considering the indeterminate results, we cannot suggest that dose escalation is correlated with OS. The oligometastasis status might be related to better OS, considering the high consistency of results and plausibility with low to moderate quality of evidence. Hypofractionated EBRT might yield comparable efficacy to conventional EBRT, with a low-quality grade of evidence. There were few complications of grade ≥3, except for hematologic complications, which ranged from 11.5to 34%.

CONCLUSION

EBRT is an efficient and feasible palliative option. Clinical consideration of hematologic complications is necessary. Future studies are needed to increase the quality of evidence for actual clinical questions. ^†Reference to a system of the American Society for Radiation Oncology primary liver cancer clinical guidelines.

Development and validation of a nomogram for predicting the cancer-specific survival of fibrolamellar hepatocellular carcinoma patients

Fibrolamellar hepatocellular carcinoma (FLC) is a rare subtype of hepatocellular carcinoma. Our study aimed to construct a nomogram to predict the cancer-specific survival (CSS) of FLC. Data of 200 FLC patients enrolled in the Surveillance, Epidemiology, and End Results (SEER) database were divided into the training group and the validation group. Prognostic factors identified in the univariate and multivariate Cox regression analyses were used to construct the nomogram. The concordance index (C-index), calibration curves, time-dependent receiver operating characteristic curve (ROC), and decision curve analysis (DCA) were used to evaluate the performance of the nomogram. As a result, age ≥ 59, N1 stage, M1 stage, tumor size ≤ 2.0 cm, and no surgery were significantly associated with lower CSS in multivariate Cox regression analysis. The calibration plot showed good consistency of the nomogram between predicted and observed outcomes in the training and validation groups. Compared with the TNM staging system, the prognostic evaluation model (PEM) showed a higher C-index (0.823 vs 0.656). The PEM also showed better predictive performance, with areas under the curve of 0.909 and 0.890 for predicting the 1- and 5-year survival. The AUCs of the TNM stage model for predicting 1- and 5-year survival were 0.629 and 0.787, respectively. In addition, the DCA curve showed that the nomogram had better clinical utility. Finally, we concluded that Age, N stage, M stage, tumor size, and surgery are independent prognostic factors for FLC. PEM established based on these five prognostic indicators can help predict the CSS of patients with FLC.

Hypofractionation in Hepatocellular Carcinoma - The Effect of Fractionation Size

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

Will the collaboration of surgery and external radiotherapy open new avenues for hepatocellular carcinoma with portal vein thrombosis?

Portal invasion of hepatocellular carcinoma (HCC) occurs in 12.5%-40% of patients diagnosed with cancer and yields poor clinical outcomes. Since it is a common cause of inoperability, sorafenib was regarded as the standard treatment for HCC in the Barcelona Clinic of Liver Cancer guidelines. However, the median survival of the Asian population was only approximately 6 mo, and the tumor response rate was less than moderate (< 5%). Various locoregional modalities were performed, including external beam radiotherapy (EBRT), transarterial chemoembolization, hepatic arterial infusion chemotherapy, and surgery, alone or in combination. Among them, EBRT is a noninvasive method and can safely treat tumors involving the major vessels. Palliative EBRT has been commonly performed, especially in East Asian countries, where locally invasive HCC is highly prevalent. Although surgery is not commonly indicated, pioneering studies have demonstrated encouraging results in recent decades. Furthermore, the combination of neo- or adjuvant EBRT and surgery has been recently used and has significantly improved the outcomes of HCC patients, as reported in a few randomized studies. Regarding systemic modality, a combination of novel immunotherapy and vascular endothelial growth factor inhibitor showed results superior to that of sorafenib as a first-line agent. Future clinical trials investigating the combined use of these novel agents, surgery, and EBRT are expected to improve the prognosis of HCC with portal invasion.

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.

Differences in radiotherapy application according to regional disease characteristics of hepatocellular carcinoma

There are differences in opinion regarding the application of external beam radiotherapy in the treatment of hepatocellular carcinoma. Some major guidelines state that external beam radiotherapy is yet to attain a sufficient level of evidence. However, caution should be exercised when attempting to understand the clinical need for external beam radiotherapy solely based on the level of evidence. Previously, external beam radiotherapy had low applicability in the treatment of hepatocellular carcinoma before computed tomography-based planning was popularized. Modern external beam radiotherapy can selectively target tumor cells while sparing normal liver tissues. Recent technologies such as stereotactic body radiotherapy have enabled more precise treatment. The characteristics of hepatocellular carcinoma differ significantly according to the regional etiology. The main cause of hepatocellular carcinoma is the hepatitis B virus. It is commonly diagnosed as a locally advanced tumor but with relatively preserved hepatic function. The majority of these hepatocellular carcinoma cases are found in the East Asian population. Hepatocellular carcinoma caused by hepatitis C virus or other benign hepatitis tends to be diagnosed as a less locally aggressive tumor but with deteriorated liver function. The western world and Japan tend to have patients with such causes. External beam radiotherapy has been more commonly performed for the former, although the use of external beam radiotherapy in the latter might have more concerns with regard to hepatic toxicity. This review discusses the above subjects along with perspectives regarding external beam radiotherapy in recent guidelines.

ALKBH5-Modified HMGB1-STING Activation Contributes to Radiation Induced Liver Disease via Innate Immune Response

PURPOSE

Radiation therapy, which is vital for the treatment of primary liver cancer, comes with unavoidable liver injury, which limits its implementation. N6-methyladenosine (m6A) methylation is involved in many molecular functions. However, its role in radiation-induced liver diseases (RILD) remains unknown. Herein, we investigate the role of m6A methylation in RILD.

METHODS AND MATERIALS

Methylated RNA-immunoprecipitation sequencing and RNA transcriptome sequencing were used to reveal the methylation pattern of human hepatic stellate cells (HSCs) exposed to irradiation. C3H/HeN mice and stimulator of interferon genes (STING)-deficient mice underwent x-ray irradiation of 24 Gy in 3 fractions. The m6A methylation of the high-mobility group box 1 (HMGB1) transcript was validated using methylated RNA immunoprecipitation, RNA immunoprecipitation, luciferase assays, and a messenger RNA decay assay.

RESULTS

Human hepatic stellate cells showed significant differences in methylation patterns after 8 Gy of x-ray irradiation. Irradiation recruited AlkB homolog 5 (ALKBH5) to demethylate m6A residues in the 3' untranslated region of HMGB1, which resulted in the activation of STING-interferon regulatory factor 3 signaling. Changes in the transcription of the 3' untranslated region of HMGB1 occurred after the knockdown of ALKBH5, which were eliminated after m6A residue mutation. Strikingly, ALKBH5 deficiency or HMGB1 silencing both attenuated type I interferon production and decreased hepatocyte apoptosis. In vivo depletion of ALKBH5 abolished the upregulation of HMGB1-mediated STING signaling and decreased liver inflammation, which was consistent with STING^-/- mice treated with irradiation. Notably, YTHDF2 (m6A reader protein) directly bound to HMGB1 m6A-modified sites and promoted its degradation.

CONCLUSIONS

ALKBH5-dependent HMGB1 expression mediates STING-interferon regulatory factor 3 innate immune response in RILD.

Stereotactic radiotherapy for hepatocellular carcinoma: Expanding the multidisciplinary armamentarium

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third most common cause of cancer-related death. Long-term prognosis remains poor with treatment options frequently limited by advanced tumor stage, tumor location, or underlying liver dysfunction. Stereotactic ablative body radiotherapy (SABR) utilizes technological advances to deliver highly precise, tumoricidal doses of radiation. There is an emerging body of literature on SABR in HCC demonstrating high rates of local control in the order of 80-90% at 3 years. SABR is associated with a low risk of radiation-induced liver disease or decompensation in appropriately selected HCC patients with compensated liver function and is now being incorporated into guidelines as an additional treatment option. This review outlines the emerging role of SABR in the multidisciplinary management of HCC and summarizes the current evidence for its use as an alternative ablative option for early-stage disease, as a bridge to transplant, and as palliation for advanced-stage disease. We outline specific considerations regarding patient selection, toxicities, and response assessment. Finally, we compare current international guidelines and recommendations for the use of SABR and summarize ongoing studies.

Stereotactic Radiotherapy for Hepatocellular Carcinoma, Radiosensitization Strategies and Radiation-Immunotherapy Combination

Simple Summary

Radiotherapy is rapidly turning into a crucial component of multidisciplinary treatment for liver cancer because many patients are not surgical treatment candidates. Thanks to technical developments, radiotherapy have achieved high precision treatments, making it possible to eliminate tumor cells without severe damage to the liver and other organs. Stereotactic Body Radiation Therapy is an advanced radiotherapy technique able to eradicate malignant tumors wherever they are located in properly selected patients. The best use of radiotherapy, the most fruitful radiotherapy strategy, and the best way to combine it with other treatments for liver cancer are largely unknown. Radiosensitizers, agents that can potentiate radiotherapy, could broaden the radiotherapeutic landscape. Radiotherapy potentiation can be achieved with diverse treatments, not only drugs but also nanoparticles. In order to clear up the performance of radiotherapy in liver cancer management in the future and the best ways to potentiate its effects, considerable medical research is needed.

Abstract

Stereotactic body radiotherapy (SBRT) is an emerging ablative modality for hepatocellular carcinoma (HCC). Most patients with HCC have advanced disease at the time of diagnosis, and therefore, are not candidates for definitive-intent therapies such as resection or transplantation. For this reason, various alternative local and regional therapies have been used to prevent disease progression, palliate symptoms, and delay liver failure. Stereotactic body radiation therapy is a non-invasive technique of delivering ablative doses of radiation to tumors while sparing normal or non-tumor hepatic tissue. Incorporation of SBRT in multidisciplinary HCC management is gradual, initially applied when other liver-directed therapies have failed or are contraindicated, and tried in combination with other locoregional or systemic therapies for more unfavorable conditions by more experienced teams. In order to improve SBRT therapeutic ratio, there has been much interest in augmenting the effect of radiation on tumors by combining it with chemotherapy, molecularly targeted therapeutics, nanoparticles, and immunotherapy. This review aims to synthesize available evidence to evaluate the clinical feasibility and efficacy of SBRT for HCC, and to explore novel radio-potentiation concepts by combining SBRT with novel therapeutics. It is expected that those approaches would result in improved therapeutic outcomes, even though many questions remain with regard to the optimal way to assemble treatments. Further trials are needed to evaluate and consolidate these promising therapies for HCC.

Radiofrequency ablation and stereotactic body radiotherapy for hepatocellular carcinoma: should they clash or reconcile?

Until a few decades ago, surgical resection was the only valid option for treating hepatocellular carcinoma (HCC). However, various locoregional modalities including arterial-directed therapy, radiofrequency ablation (RFA), and radiotherapy have been recently shown to be effective. RFA is now established as a standard treatment for small localized HCCs, showing oncological results comparable to those of surgical resection in randomized studies. Stereotactic body radiotherapy (SBRT) is a modern radiotherapeutic modality that targets tumors with precision and delivers high radiation doses over a short period of time; it has particularly attracted clinical interest after its therapeutic efficacy was found to be similar to that of surgery in early-stage lung cancer. Given its potent disease control capability, SBRT has also been applied to early HCCs and demonstrated promising results in recent studies. It has also been noted for its suitability to treat tumors located in anatomical locations where RFA would be challenging. However, since its effectiveness has not been compared to that of RFA in randomized studies of patients eligible for RFA, the use of SBRT has been debated. This review was conducted to guide physicians from all fields involved in the treatment of early HCC. The therapeutic characteristics and indications of both SBRT and RFA are described, and recent comparative studies between the two modalities are discussed. In addition, we examined the factors that should be considered when selecting the appropriate treatments, and offer our recommendations.

[Stereotaxic radiotherapy of primary extracranial tumors]

Stereotactic radiotherapy is a fundamental change from the conventional fractionated radiotherapy and represents a new therapeutic indication. Stereotactic radiotherapy is now a standard of care for inoperable patients or patients who refuse surgery. The results are encouraging with local control and survival rates very high in selected populations. The rate of late toxicity remains acceptable. Good tolerability makes it appropriate even for elderly and frail patients. In these fragile patients or in certain specific clinical situations, different surgical, radiotherapy or interventional radiology attitudes can be discussed on a case-by-case basis. These situations are considered in this article for the pulmonary, hepatic and prostatic localizations.