Radiation-associated liver injury

Hepatocellular carcinoma effective stereotactic body radiotherapy using Gold Anchor and the Synchrony system: Two case reports and review of literature

BACKGROUND

Radiotherapy for hepatocellular carcinoma (HCC) is considered to have limited efficacy because of treatment intensity considering that the irradiated area includes the liver, which is highly radiosensitive. In this report, we present two cases in which tumor control by surgical resection, radiofrequency ablation, transcatheter arterial chemoembolization (TACE), and lenvatinib administration was difficult, but stereotactic body radiotherapy (SBRT) using the Synchrony system by Radixact™ and Gold Anchor^® (GA) was effective.

CASE SUMMARY

A 60-year-old man had a single 10-cm HCC in the right lobe. Viable lesions remained after TACE, and levels of alpha-fetoprotein and protein induced by vitamin K antagonists II (PIVKA-II) decreased and quickly re-elevated. We performed SBRT with GA. Three weeks after implantation, localized radiotherapy (SBRT; 40 Gy/5 fractions) was performed using the Synchrony system by Radixact™. Four weeks later, the viable lesion had disappeared, and the PIVKA-II levels decreased. A 77-year-old man had a single 12-cm HCC in the right lobe. The patient experienced recurrence after hepatectomy. Further recurrence occurred after TACE, and we performed SBRT with GA. Because of the proximity of the HCC to the gastrointestinal tract, localized radiotherapy (SBRT; 39 Gy/13 fractions) to the HCC was performed 3 wk after implantation using the Synchrony system by Radixact™. Four weeks later, the viable lesion had disappeared on computed tomography, and the PIVKA-Ⅱ levels decreased.

CONCLUSION

SBRT using the Synchrony system and GA can deliver a large dose accurately and safely, and could have a high therapeutic effect.

EANM dosimetry committee recommendations for dosimetry of 177Lu-labelled somatostatin-receptor- and PSMA-targeting ligands

The purpose of the EANM Dosimetry Committee is to provide recommendations and guidance to scientists and clinicians on patient-specific dosimetry. Radiopharmaceuticals labelled with lutetium-177 (177Lu) are increasingly used for therapeutic applications, in particular for the treatment of metastatic neuroendocrine tumours using ligands for somatostatin receptors and prostate adenocarcinoma with small-molecule PSMA-targeting ligands. This paper provides an overview of reported dosimetry data for these therapies and summarises current knowledge about radiation-induced side effects on normal tissues and dose-effect relationships for tumours. Dosimetry methods and data are summarised for kidneys, bone marrow, salivary glands, lacrimal glands, pituitary glands, tumours, and the skin in case of radiopharmaceutical extravasation. Where applicable, taking into account the present status of the field and recent evidence in the literature, guidance is provided. The purpose of these recommendations is to encourage the practice of patient-specific dosimetry in therapy with 177Lu-labelled compounds. The proposed methods should be within the scope of centres offering therapy with 177Lu-labelled ligands for somatostatin receptors or small-molecule PSMA.

Stereotactic body radiation therapy as a salvage treatment for single viable hepatocellular carcinoma at the site of incomplete transarterial chemoembolization: a retrospective analysis of 302 patients

BACKGROUND

To evaluate the clinical outcomes of patients who received stereotactic body radiation therapy (SBRT) for single viable hepatocellular carcinoma (HCC) at the site of incomplete transarterial chemoembolization (TACE).

METHODS

Patients treated with SBRT for single viable HCC after incomplete TACE between 2012 and 2017 at Asan Medical Center (Seoul, South Korea) were included. Incomplete TACE was defined as (1) evidence of viable HCC at the site of TACE on follow-up dynamic computed tomography (CT) or magnetic resonance imaging following one or more consecutive TACEs, (2) no definite tumor staining on superselective hepatic angiogram, or (3) no definite iodized oil uptake on post-embolization angiogram or CT. Doses of 10-15 Gy per fraction were given over 3-4 consecutive days. The primary outcome was local control rate at 3 years and secondary outcome included tumor response, overall survival rate, out-of-field intrahepatic recurrence-free survival, distant metastasis-free survival and treatment-related toxicities. Treatment-related adverse events were evaluated according to the common terminology criteria for adverse events, version 4.03.

RESULTS

A total of 302 patients were analyzed. The median follow-up duration was 32.9 months (interquartile range [IQR], 23.6-41.7) and the median tumor size was 2.0 cm (range, 0.7-6.9). The local control (LC) and overall survival rates at 3 years were 91.2 and 72.7%, respectively. 95.4% of the tumors reached complete response (CR) during the entire follow-up period (anyCR). The median interval from SBRT to anyCR was 3.4 months (IQR, 1.9-4.7), and 39.9 and 83.3% of the lesions reached CR at 3- and 6-months after SBRT, respectively. Radiation-induced liver disease was observed in 8 (2.6%) patients. No patients experienced gastroduodenal bleeding within the radiation field.

CONCLUSION

SBRT could be considered a feasible salvage treatment option for HCC after incomplete TACE.

Radioembolization of Hepatocellular Carcinoma with 90Y Glass Microspheres: No Advantage of Voxel Dosimetry with Respect to Mean Dose in Dose-Response Analysis with Two Radiological Methods

Simple Summary

We confirmed that the non-uniformity of an intra-lesion dose distribution, which was introduced in calculations as voxel dosimetry, did not significantly improve the AUC values of the dose–response relationship with respect to the mean dose. This was probably derived from the strong correlations (all p < 0.0001) among all voxel-based dosimetric variables (minimum Spearman correlation coefficient: 0.67) caused by the limited spatial resolution of nuclear medicine images. Responses were assessed with mRECIST and with an experimental densitometric method with a response threshold optimized at 20% HU variation. Significant dose–response agreement was obtained only with the densitometric method and only with post-therapy 90Y-PET data. More unexpectedly, the injection of Theraspheres™ on day 8 from the reference date rather than on day 4 worsened the dose–response correlation and reduced the efficacy at high doses. This may be explained by the increased non-uniformity following the non-linear mega-clustering effect triggered by the higher number of microspheres/GBq injected on day 8.

Abstract

In this confirmatory study, we tested if a calculation that included the non-uniformity of dose deposition through a voxel-based dosimetric variable Ψ was able to improve the dose–response agreement with respect to the mean absorbed dose D. We performed dosimetry with ^99mTc-MAA SPECT/CT and ⁹⁰Y-PET/CT in 86 patients treated 8 instead of 4 days after the reference date with 2.8 times more ⁹⁰Y glass microspheres/GBq than in our previous study. The lesion-by-lesion response was assessed with the mRECIST method and with an experimental densitometric criterion. A total of 106 lesions were studied. Considering Ψ as a prognostic response marker, having no Ψ provided a significantly higher AUC than D. The correlation, t-test, and AUC values were statistically significant only with the densitometric method and only with post-therapy dosimetry. In comparison with our previous study, the dose–response correlation and AUC values were poorer (maximum r = 0.43, R² = 0.14, maximal AUC = 0.71), and the efficacy at a high dose did not reach 100%. The expected advantages of voxel dosimetry were nullified by the correlation between any Ψ and D due to the limited image spatial resolution. The lower AUC and efficacy may be explained by the mega-clustering effect triggered by the higher number of microspheres/GBq injected on day 8.

Alpinetin: A Review of Its Pharmacology and Pharmacokinetics

Flavonoids isolated from medicinal herbs have been utilized as valuable health-care agents due to their virous biological applications. Alpinetin is a natural flavonoid that emerges in many widely used medicinal plants, and has been frequently applied in Chinese patent drugs. Accumulated evidence has demonstrated that alpinetin possesses a broad range of pharmacological activities such as antitumor, antiinflammation, hepatoprotective, cardiovascular protective, lung protective, antibacterial, antiviral, neuroprotective, and other properties through regulating multiple signaling pathways with low systemic toxicity. However, pharmacokinetic studies have documented that alpinetin may have poor oral bioavailability correlated to its extensive glucuronidation. Currently, the reported pharmacological properties and pharmacokinetics profiles of alpinetin are rare to be scientifically reviewed. In this article, we aimed to highlight the mechanisms of action of alpinetin in various diseases to strongly support its curative potentials for prospective clinical applications. We also summarized the pharmacokinetics properties and proposed some viable strategies to convey an appreciable reference for future advances of alpinetin in drug development.

Activation of p53 After Irradiation Impairs the Regenerative Capacity of the Mouse Liver

Radiation therapy is one of the treatment methods for hepatocellular carcinoma. However, radiation tolerance of the liver is low, and the detailed effect of radiation on liver regeneration has not been clarified. C57BL/6J mice or hepatocyte-specific p53 knockout (KO) mice (albumin [Alb]-Cre Trp53flox/flox ) were irradiated with a single fraction of 10 Gy localized to the upper abdomen. We performed 70% partial hepatectomy (PHx) 24 hours after irradiation. Liver regeneration was assessed by proliferation cell nuclear antigen (PCNA)- and Ki-67-positive hepatocyte ratios and liver-to-body weight ratio after PHx. To establish a fibrosis model, CCl4 was orally administered for 8 weeks. The murine hepatocyte cell line BNL CL.2 (CL2) was irradiated with 10 Gy. Irradiation activated p53, induced downstream p21 in the liver, and delayed liver regeneration after PHx. While PHx increased hepatocyte growth factor (HGF) levels and activated Met with or without irradiation in the regenerative liver, it activated Akt and extracellular kinase 1 and 2 (Erk 1/2) less in irradiated mice than in nonirradiated mice. In CL2 cells cultured with HGF, irradiation suppressed cell growth by decreasing phosphorylated Akt and Erk 1/2 levels, which was abolished by small interfering RNA-mediated p53 knockdown but not by p21 knockdown. Hepatocyte-specific knockout of p53 in mice abolished the irradiation-induced suppression of both liver regeneration and Akt and Erk 1/2 activation after PHx. In the fibrotic mouse model, the survival rate after PHx of irradiated p53 KO mice was higher than that of wild-type mice. Conclusion: p53 but not p21 is involved in the impaired regenerative ability of the irradiated liver.

Predictive Modeling of Survival and Toxicity in Patients With Hepatocellular Carcinoma After Radiotherapy

PURPOSE

To stratify patients and aid clinical decision making, we developed machine learning models to predict treatment failure and radiation-induced toxicities after radiotherapy (RT) in patients with hepatocellular carcinoma across institutions.

MATERIALS AND METHODS

The models were developed using linear and nonlinear algorithms, predicting survival, nonlocal failure, radiation-induced liver disease, and lymphopenia from baseline patient and treatment parameters. The models were trained on 207 patients from Massachusetts General Hospital. Performance was quantified using Harrell's c-index, area under the curve (AUC), and accuracy in high-risk populations. Models' structures were optimized in a nested cross-validation approach to prevent overfitting. A study analysis plan was registered before external validation using 143 patients from MD Anderson Cancer Center. Clinical utility was assessed using net-benefit analysis.

RESULTS

The survival model stratified high-risk versus low-risk patients well in the external validation cohort (c-index = 0.75), better than existing risk scores. Predictions of 1-year survival and nonlocal failure were excellent (external AUC = 0.74 and 0.80, respectively), especially in the high-risk group (accuracy > 90%). Cause-of-death analysis showed differential modes of treatment failure in these cohorts and indicated that these models could be used to stratify RT patients for liver-sparing treatment regimen or combination approaches with systemic agents. Predictions of liver disease and lymphopenia were good but less robust (external AUC = 0.68 and 0.7, respectively), suggesting the need for more comprehensive consideration of dosimetry and better predictive biomarkers. The liver disease model showed excellent accuracy in the high-risk group (92%) and revealed possible interactions of platelet count with initial liver function.

CONCLUSION

Machine learning approaches can provide reliable outcome predictions in patients with hepatocellular carcinoma after RT in diverse cohorts across institutions. The excellent performance, particularly in high-risk patients, suggests novel strategies for patient stratification and treatment selection.

Ambient temperature structures the gut microbiota of zebrafish to impact the response to radioactive pollution

Potential nuclear accidents propel serious environmental pollution, and the resultant radionuclide release devastates severely the environment severely and threatens aquatic organism survival. Likewise, ongoing climate change coupled with the gradual increase in global surface temperatures can also adversely impact the aquatic ecosystems. In the present study, we preconditioned zebrafish (Danio rerio) at three different temperatures (18 °C, 26 °C and 34 °C) to investigate the effects of a temperature profile on their radiosensitivity (exposure to 20 Gy of gamma rays) to identify the potential biochemical mechanism responsible for influencing radiosensitivity. We found that preconditioning of zebrafish at different temperatures moulded specific gut microbiota configurations and impacted hepatic glycometabolism and sensitivity to subsequent radiation. Following antibiotic treatment to reduce gut bacteria, these observed differences in the expression of hepatic glycometabolism-related genes and radiation-induced intestinal toxicity were minimal, supporting the hypothesis that the gut bacteria reshaped by different ambient temperatures might be the key modulators of hepatic functions and radiosensitivity in zebrafish. Together, our findings provide novel insights into the connection of radiation injuries with temperature alterations in fish, and suggest that maintaining the stability of gram-positive bacteria may be efficacious to protect aquatic organisms against short or long-term radioactive contamination in the context of global climate change.

Technical feasibility and clinical evaluation of 4D-MRI guided liver SBRT on the MR-linac

PURPOSE

Image-guided stereotactic body radiation therapy (SBRT) is an important local treatment for liver metastases. MRI-guidance enables direct tumor visualization, eliminating fiducial marker implantation. The purpose of this study was to test technical feasibility of our 4D-MRI guided liver SBRT workflow. Additionally, intra-fraction target motion and consequent target-coverage were studied.

MATERIALS&METHODS

Patients with liver metastases were included in this sub-study of the prospective UMBRELLA clinical trial. Patients received mid-position (midP) SBRT. The daily adapt-to-position workflow included localization, verification and intra-fraction tumor midP monitoring using 4D-MRI. Technical feasibility was established based on persistence of the treatment protocol, treatment time ≤1 hour, no geographical miss and no unexpected acute toxicity grade >3. All 4D-MRIs were registered to the planning midP-CT and tumor midP and amplitude were calculated. Additionally, delivered target dose was accumulated incorporating the 4D-MRI intra-fraction tumor motion and evaluated with Monte-Carlo error simulations.

RESULTS

20 patients with liver metastases were included and treated with 4D-MRI guided SBRT. Feasibility criteria were met in all-but-one patient. No grade ≥3 acute toxicity was observed. Group mean (M), systematic and random midP-drifts were 2.4mm, 2.6mm and 3.1mm in CC-direction. 4D-MRI tumor CC-amplitudes were reduced compared to the simulation 4D-CT (M=-1.9mm) and decreased during treatment (M=-1.4mm). Dose accumulation showed adquate target-coverage on a population level.

CONCLUSION

We successfully demonstrated technical feasibility of 4D-MRI guided SBRT in a cohort of 20 patients with liver metastases. However, substantial midposition drifts occurred which stress the need for intra-fraction motion management strategies to further increase the precision of treatment delivery.

Characterization of rib fracture development following liver directed stereotactic body radiation therapy

Purpose

Rib fractures are a well-described complication following thoracic stereotactic body radiation therapy (SBRT). However, there are limited data in the setting of liver-directed SBRT.

Methods

Patients who underwent liver SBRT from 2014 to 2019 were analyzed. Logistic regression models were used to identify the demographic, clinical, and dosimetric factors associated with the development of rib fractures.

Results

Three hundred and forty-three consecutive patients were reviewed with median follow-up of 9.3 months (interquartile range [IQR]: 4.7-17.4 months); 81% of patients had primary liver tumors and 19% had liver metastases. Twenty-one patients (6.2%) developed rib fractures with a median time to diagnosis of 7 months following SBRT (IQR: 5-19 months). Of those patients, 11 experienced concomitant chest wall pain, while 10 patients had an incidental finding of a rib fracture on imaging. On univariate analysis, female gender (odds ratio [OR]: 2.29; p = 0.05), V30 Gy (OR: 1.02; p < 0.001), V40 Gy (OR: 1.08; p < 0.001), maximum chest wall dose (OR: 1.1; p < 0.001), and chest wall D30 cm³ (OR: 1.09; p < 0.001) were associated with an increased probability of developing a rib fracture. On multivariate analysis, maximum chest wall dose (OR: 1.1; p < 0.001) was associated with developing a rib fracture. Receipt of more than one course of SBRT (p = 0.34), left versus right sided lesion (p = 0.69), osteoporosis (p = 0.54), age (p = 0.82), and PTV volume (p = 0.55) were not significant.

Conclusions

Rib fractures following liver SBRT were observed in 6.2% of patients with the majority being asymptomatic. To mitigate this risk, clinicians should minimize dose delivery to the chest wall. Female patients may be at increased risk.

Feasibility of marker-less stereotactic body radiotherapy for hepatocellular carcinoma

BACKGROUND

The feasibility of marker-less stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) has not yet been established, and, thus, was examined in the present study.

MATERIAL AND METHODS

We retrospectively investigated patients who received marker-less SBRT for locally untreated HCC tumors between July 2005 and December 2018. Radiotherapy planning CT was performed under fixation with vacuum cushions and abdominal compression. The clinical target volume (CTV) was equivalent to the gross tumor volume (GTV). The internal target volume (ITV) margin to CTV was determined from calculations based on the motion of the diaphragm. The planning target volume (PTV) margin to ITV was 5-6 mm. In the set-up, radiotherapy planning CT and linac-integrated cone-beam CT performed in the same imaging and fixation settings were merged by referring to the anatomical components surrounding target tumors. The primary endpoint was the 3-year cumulative local tumor progression rate. The upper limit of the 95% confidence interval for the 3-year cumulative local tumor progression rate was less than 7.0%, which was interpreted as favorable local control and feasible for marker-less SBRT. Local tumor progression was assessed by mRECIST.

RESULTS

We reviewed 180 patients treated with 35-40 Gy/5 fractions. The median follow-up time for the local tumor progression of censored tumors was 32.3 months (range, 0.3-104). The 3-year cumulative local tumor progression rate was 3.0% (95% CI, 1.1-6.5%). The 3-year overall survival rate was 71.6% (95% CI, 63.5-78.2%). Regarding acute hematologic toxicities, grade 3 hypoalbuminemia and thrombocytopenia were detected in 1 (0.6%) and 5 (2.9%) patients, respectively. Treatment-related death from SBRT was not observed. SBRT was initiated within 7 days after radiotherapy planning CT for 84% (152/180) of patients.

CONCLUSIONS

Marker-less SBRT for HCC achieved favorable local control that fulfilled the threshold. This result suggests that marker-less SBRT with appropriate settings is a feasible treatment strategy.

Organs at risk radiation dose constraints

Dose constraints are essential for performing dosimetry, especially for intensity modulation and for radiotherapy under stereotaxic conditions. We present the update of the recommendations of the French society of oncological radiotherapy for the use of these doses in classical current practice but also for reirradiation.

Degree of reduction in normal liver complication probability from free-breathing to breath-hold liver SBRT: a dose-escalation strategy using radiation dose-volume effect

Introduction. This study aimed to analyze the degree of reduction in normal liver complication probability (NTCP) from free-breathing (FB) to breath-hold (BH) liver SBRT. The effect of the radiation dose-volume on the mean liver dose (MLD) was also analyzed due to dose prescription, normal liver volume (NLV), and PTV.Materials and Methods. Thirty-three stereotactic body radiation therapy (SBRT) cases of hepatocellular carcinoma were selected, retrospectively. For FB, the treatments were planned on average intensity projection scan (CT_avg), and patient-specific internal target volume (ITV) margins were applied. To simulate the BH treatment, computed tomography (CT) scan correspond to the 40%-50% of the respiratory cycle (CT_40%-50%) was chosen, and an appropriate intrafraction margin of 2 mm, 1.5 mm, and 1.5 mm were given in craniocaudal (CC), superior-inferior (SI), and lateral direction to generate the final iGTV. As per RTOG 1112, all organs at risk (OAR's) were considered during the optimization of treatment plans. NTCP was calculated using LKB fractionated model. Multivariate regression analysis was performed to see the effect of EQD_2Gy, NLV, and PTV on MLD_2Gy.Results.A significant dosimetric difference was observed in the normal liver (liver-ITV/iGTV). A reduction of 1.7% in NTCP was observed from FB to BH technique. The leverage of dose escalation is more in BH because MLD_2Gycorresponds to 5%, 10%, 20%, and 50% NTCP was 0.099 Gy, 0.41 Gy, 1.21 Gy, and 3.432 Gy more in BH as compared to FB technique. In MVRA, the major factor which was attributed to a change in MLD_2Gyis EQD_2Gy. Conclusion. From FB to BH technique, a significant reduction in NTCP was observed. The dose prescription is a major factor attributed to the change in MLD_2Gy. Advances in knowledge: If feasible, prefer BH treatment either for tumor dose escalation or for the reduction in NTCP.

Hepatic tumours and radiotherapy

We present the update of the recommendations of the French society of oncological radiotherapy on hepatic tumours. Recent technological progress led to develop the concept of focused liver radiation therapy. We must distinguish primary and secondary tumours, as the indications are restricted and must be discussed as an alternative to surgical or medical treatments. The tumour volume, its liver location close to the organs at risk determine the irradiation technique (repositioning method, total dose delivered, dose fractionation regimens). Tumour (and liver) breathing related motions should be taken into account. Strict dosimetric criteria must be observed with particular attention to the dose-volume histograms of non-tumoral liver as well as of the hollow organs, particularly in case of hypofractionated high dose radiotherapy "under stereotaxic conditions". Stereotactic body radiotherapy is being evaluated and is often preferred to radiofrequency for primary or secondary tumours (usually less than 5cm). An adaptation can be proposed, with a conformal fractionated irradiation protocol with or without intensity modulation, for hepatocellular carcinomas larger than 5cm.

Granulocyte Colony-Stimulating Factor Treatment Before Radiotherapy Protects Against Radiation-Induced Liver Disease in Mice

Radiation-induced liver disease (RILD) remains a major problem resulting from radiotherapy. In this scenario, immunotherapy with granulocyte colony-stimulating factor (G-CSF) arises as an attractive approach that might improve the injured liver. Here, we investigated G-CSF administration’s impact before and after liver irradiation exposure using an association of alcohol consumption and local irradiation to induce liver disease model in C57BL/6 mice. Male and female mice were submitted to a previous alcohol-induced liver injury protocol with water containing 5% alcohol for 90 days. Then, the animals were treated with G-CSF (100 μg/kg/d) for 3 days before or after liver irradiation (18 Gy). At days 7, 30, and 60 post-radiation, non-invasive liver images were acquired by ultrasonography, magnetic resonance, and computed tomography. Biochemical and histological evaluations were performed to verify whether G-CSF could prevent liver tissue damage or reverse the acute liver injury. Our data showed that the treatment with G-CSF before irradiation effectively improved morphofunctional parameters caused by RILD, restoring histological arrangement, promoting liver regeneration, preserving normal organelles distribution, and glycogen granules. The amount of OV-6 and F4/80-positive cells increased, and α-SMA positive cells’ presence was normalized. Additionally, prior G-CSF administration preserved serum biochemical parameters and increased the survival rates (100%). On the other hand, after irradiation, the treatment showed a slight improvement in survival rates (79%) and did not ameliorate RILD. Overall, our data suggest that G-CSF administration before radiation might be an immunotherapeutic alternative to radiotherapy planning to avoid RILD.

Narrative review of the role of yttrium-90 selective internal radiation therapy in the surgical management of colorectal liver metastases

The management of colorectal liver metastasis (CRLM) is complicated and benefits from a multidisciplinary team approach. Liver-directed therapy has been emerging as a modality for better progression-free control. In its early years, selective internal radiation therapy (SIRT) with yttrium-90 (Y-90) was confined as an end-of-line therapy. However, literature has supported other roles including: a first-line treatment for CRLM alone or in combination with systemic chemotherapy; an adjunct to second or third-line chemotherapy; and a salvage treatment for chemo-refractory disease. Although future liver remnant (FLR) hypertrophy may take 3-12 months, the SIRT effect on loco-regional disease control has rendered it to be a useful tool in some pathologies with certain strategic goals. This paper reviews the use of SIRT with Y-90 in a surgical treatment pathway. This includes: (I) an element of multidisciplinary treatment of low-volume CRLMs, (II) convert an R1 to R0 resection by sterilizing the margins of tumor near critical structures, and (III) radiation lobectomy to induce contralateral hypertrophy in order to aid in a safer resection. There are many opportunities to validate the role of SIRT as a first-line therapy along with surgical resection including an umbrella clinical trial design.

Stereotactic body radiation therapy versus radiofrequency ablation for single small hepatocellular carcinoma: a propensity-score matching analysis of their impact on liver function and clinical outcomes

Background

Stereotactic body radiation therapy (SBRT) has high efficacy for early-stage hepatocellular carcinoma (HCC) and is an accepted alternative to radiofrequency ablation (RFA). However, SBRT for HCC may cause subacute liver injury leading to negative clinical outcomes. In this study, we compared changes of liver function and prognosis after SBRT or RFA in patients with single, small HCC by using a propensity-score matching analysis.

Methods

We reviewed medical records of 140 patients with single ≤3 cm HCC treated with SBRT or RFA at Kurashiki Central Hospital between January 2014 and February 2019. Changes of albumin-bilirubin (ALBI) score, local recurrence, and overall survival were compared between the propensity-score matched groups (31 patients treated with SBRT and 62 treated with RFA).

Results

The ALBI score increased modestly but significantly after SBRT, while it was unchanged in the RFA group; the intergroup difference was statistically significant (P=0.004). No local recurrence was identified in the SBRT group, whereas the cumulative recurrence incidence was 9.7% in the RFA group (P=0.023). Overall survival was not significantly different between the two groups (hazard ratio: 1.32, 95% confidence interval: 0.60-2.89, P=0.401).

Conclusions

SBRT had modestly negative impact on liver function but with appraisable local control of HCC. Our findings should contribute to the selection of this modality for treatment of single, small HCC.

Stereotactic body radiation therapy versus radiofrequency ablation in patients with small hepatocellular carcinoma: a systematic review and meta-analysis

Background

This study aimed to compare the clinical outcomes and toxicity between small hepatocellular carcinoma (HCC) patients treated with stereotactic body radiation therapy (SBRT) and those treated with radiofrequency ablation (RFA).

Methods

We searched databases for relevant clinical studies. The primary outcomes of interest were overall survival (OS) at 1 and 2 years, freedom from local progression (FFLP) rate at 2 years, and complications.

Results

Five cohorts from 5 retrospective studies and 4,814 patients with HCC were included. Pooled OS at 2 years was significantly lower for SBRT than for RFA [odds ratio (OR): 0.63; 95% confidence interval (CI): 0.51-0.79; P<0.0001], but the pooled FFLP rate at 2 years was higher for SBRT than for RFA (OR: 1.66; 95% CI: 1.05-2.61; P=0.03). In addition, there was no significant difference in the local and liver toxicities of the two treatments. The contradictory conclusion between the OS and FFLP outcome may be attributed to the difference in radiological dose and location, but there were no uniform criteria to illustrate the radiological dose and location in the included studies.

Conclusions

SBRT had a higher local control ratio but poorer prognosis than RFA in patients with small HCC. The local toxicity was comparable in both treatments. Further trials should be designed with uniform standards for SBRT and RFA treatments.

EANM dosimetry committee series on standard operational procedures: a unified methodology for 99mTc-MAA pre- and 90Y peri-therapy dosimetry in liver radioembolization with 90Y microspheres

The aim of this standard operational procedure is to standardize the methodology employed for the evaluation of pre- and post-treatment absorbed dose calculations in 90Y microsphere liver radioembolization. Basic assumptions include the permanent trapping of microspheres, the local energy deposition method for voxel dosimetry, and the patient-relative calibration method for activity quantification.The identity of 99mTc albumin macro-aggregates (MAA) and 90Y microsphere biodistribution is also assumed. The large observed discrepancies in some patients between 99mTc-MAA predictions and actual 90Y microsphere distributions for lesions is discussed. Absorbed dose predictions to whole non-tumoural liver are considered more reliable and the basic predictors of toxicity. Treatment planning based on mean absorbed dose delivered to the whole non-tumoural liver is advised, except in super-selective treatments.Given the potential mismatch between MAA simulation and actual therapy, absorbed doses should be calculated both pre- and post-therapy. Distinct evaluation between target tumours and non-tumoural tissue, including lungs in cases of lung shunt, are vital for proper optimization of therapy. Dosimetry should be performed first according to a mean absorbed dose approach, with an optional, but important, voxel level evaluation. Fully corrected 99mTc-MAA Single Photon Emission Computed Tomography (SPECT)/computed tomography (CT) and 90Y TOF PET/CT are regarded as optimal acquisition methodologies, but, for institutes where SPECT/CT is not available, non-attenuation corrected 99mTc-MAA SPECT may be used. This offers better planning quality than non dosimetric methods such as Body Surface Area (BSA) or mono-compartmental dosimetry. Quantitative 90Y bremsstrahlung SPECT can be used if dedicated correction methods are available.The proposed methodology is feasible with standard camera software and a spreadsheet. Available commercial or free software can help facilitate the process and improve calculation time.

Prospective Study of Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma on Waitlist for Liver Transplant

BACKGROUND AND AIMS

There are no prospective data on stereotactic body radiation therapy (SBRT) as a bridge to liver transplantation for HCC. This study aimed to evaluate the efficacy and safety of SBRT as bridging therapy, with comparison with transarterial chemoembolization (TACE) and high-intensity focused ultrasound (HIFU).

APPROACH AND RESULTS

Patients were prospectively enrolled for SBRT under a standardized protocol from July 2015 and compared with a retrospective cohort of patients who underwent TACE or HIFU from 2010. The primary endpoint was tumor control rate at 1 year after bridging therapy. Secondary endpoints included cumulative incidence of dropout, toxicity, and posttransplant survival. During the study period, 150 patients were evaluated (SBRT, n = 40; TACE, n = 59; HIFU, n = 51). The tumor control rate at 1 year was significantly higher after SBRT compared with TACE and HIFU (92.3%, 43.5%, and 33.3%, respectively; P = 0.02). With competing risk analysis, the cumulative incidence of dropout at 1 and 3 years after listing was lower after SBRT (15.1% and 23.3%) compared with TACE (28.9% and 45.8%; P = 0.034) and HIFU (33.3% and 45.1%; P = 0.032). Time-to-progression at 1 and 3 years was also superior after SBRT (10.8%, 18.5% in SBRT, 45%, 54.9% in TACE, and 47.6%, 62.8% in HIFU; P < 0.001). The periprocedural toxicity was similar, without any difference in perioperative complications and patient and recurrence-free survival rates after transplant. Pathological complete response was more frequent after SBRT compared with TACE and HIFU (48.1% vs. 25% vs. 17.9%, respectively; P = 0.037). In multivariable analysis, tumor size <3 cm, listing alpha-fetoprotein <200 ng/mL, Child A, and SBRT significantly reduced the risk of dropout.

CONCLUSIONS

SBRT was safe, with a significantly higher tumor control rate, reduced the risk of waitlist dropout, and should be used as an alternative to conventional bridging therapies.

Uniform versus non-uniform dose prescription for proton stereotactic body radiotherapy of liver tumors investigated by extensive motion-including treatment simulations

Compared to x-ray-based stereotactic body radiotherapy (SBRT) of liver cancer, proton SBRT may reduce the normal liver tissue dose. For an optimal trade-off between target and liver dose, a non-uniform dose prescription is often applied in x-ray SBRT, but lacks investigation for proton SBRT. Also, proton SBRT is prone to breathing-induced motion-uncertainties causing target mishit or dose alterations by interplay with the proton delivery. This study investigated non-uniform and uniform dose prescription in proton-based liver SBRT, including effects of rigid target motion observed during planning-4DCT and treatment. The study was based on 42 x-ray SBRT fractions delivered to 14 patients under electromagnetic motion-monitoring. For each patient, a non-uniform and uniform proton plan were made. The uniform plan was renormalized to be iso-toxic with the non-uniform plan using a NTCP model for radiation-induced liver disease. The motion data were used in treatment simulations to estimate the delivered target dose with rigid motion. Treatment simulations were performed with and without a repainting scheme designed to mitigate interplay effects. Including rigid motion, the achieved CTV mean dose after three fractions delivered without repainting was on average (±SD) 24.8 ± 8.4% higher and the D_98%was 16.2 ± 11.3% higher for non-uniform plans than for uniform plans. The interplay-induced increase in D_2%relative to the static plans was reduced from 3.2 ± 4.1% without repainting to -0.5 ± 1.7% with repainting for non-uniform plans and from 1.5 ± 2.0% to 0.1 ± 1.3% for uniform plans. Considerable differences were observed between estimated CTV doses based on 4DCT motion and intra-treatment motion. In conclusion, non-uniform dose prescription in proton SBRT may provide considerably higher tumor doses than uniform prescription for the same complication risk. Due to motion variability, target doses estimated from 4DCT motion may not accurately reflect the delivered dose. Future studies including modelling of deformations and associated range uncertainties are warranted to confirm the findings.

Effect of stereotactic body radiotherapy on regional metabolic liver function investigated in patients by dynamic [18F]FDGal PET/CT

Purpose

Stereotactic body radiotherapy (SBRT) is increasingly used for treatment of liver tumors but the effect on metabolic liver function in surrounding tissue is largely unknown. Using 2-deoxy-2-[¹⁸F]fluoro-d-galactose ([¹⁸F]FDGal) positron emission tomography (PET)/computed tomography (CT), we aimed to determine a dose–response relationship between radiation dose and metabolic liver function as well as recovery.

Procedures.

One male subject with intrahepatic cholangiocarcinoma and five subjects (1 female, 4 male) with liver metastases from colorectal cancer (mCRC) underwent [¹⁸F]FDGal PET/CT before SBRT and after 1 and 3 months. The dose response was calculated using the data after 1 month and the relative recovery was evaluated after 3 months. All patients had normal liver function at time of inclusion.

Results

A linear dose–response relationship for the individual liver voxel dose was seen until approximately 30 Gy. By fitting a polynomial curve to data, a mean TD₅₀ of 18 Gy was determined with a 95% CI from 12 to 26 Gy. After 3 months, a substantial recovery was observed except in tissue receiving more than 25 Gy.

Conclusions

[¹⁸F]FDGal PET/CT makes it possible to determine a dose–response relationship between radiation dose and metabolic liver function, here with a TD₅₀ of 18 Gy (95% CI 12–26 Gy). Moreover, the method makes it possible to estimate metabolic recovery in liver tissue.

Novel Clinically Weight-Optimized Dynamic Conformal Arcs (WO-DCA) for Liver SBRT: A Comparison with Volumetric Modulated Arc Therapy (VMAT)

PURPOSE

To evaluate the feasibility of shortening the duration of liver stereotactic radiotherapy (SBRT) without jeopardizing dosimetry or conformity by utilizing weight-optimized dynamic conformal arcs (WO-DCA) as opposed to volumetric modulated arc therapy (VMAT) for tumors away from critical structures.

METHODS

Nineteen patients with liver metastasis were included, previously treated with 50 Gy in 4 fractions with VMAT technique using two partial coplanar arcs of 6 MV beams delivered in high-definition multi-leaf collimator (HD-MLC). Two coplanar partial WO-DCA were generated on Pinnacle treatment planning system (TPS) for each patient; and MLC aperture around the planning target volume (PTV) was automatically generated at different margins for both arcs and maintained dynamically around the target during arc rotation. Weight of the two arcs using optimization method was adjusted between the arcs to maximize tumor coverage and protect organs at risk (OAR) based on the RTOG-0438 protocol.

RESULTS

The WO-DCA plans successfully "agreed" with the standard VMAT for OAR (liver, spinal cord, stomach, duodenum, small bowel, and heart) and PTV (Dmean, D98%, D2%, CI, and GI), with superior mean quality assurance (QA) pass rate (97.06 vs 93.00 for VMAT; P < 0.001 and t = 8.87). Similarly, the WO-DCA technique additionally reduced the beam-on time (3.26 vs 4.43; P < 0.001) and monitor unit (1860 vs 2705 for VMAT; P < 0.001) values significantly.

CONCLUSION

The WO-DCA plans might minimize small-field dosimetry errors and defeat patient-specific VMAT QA requirements due to the omission of MLC beam modulation through the target volume. The WO-DCA plans may additionally enable faster treatment delivery times and lower OAR without sacrificing target doses in SBRT of liver tumors away from critical structures.

Image-Guided Liver Stereotactic Body Radiotherapy Using VMAT and Real-Time Adaptive Tumor Gating: Evaluation of the Efficacy and Toxicity for Hepatocellular Carcinoma

Simple Summary

Although the use of stereotactic body radiation therapy (SBRT) in the management of hepatocellular carcinoma (HCC) remains unclear, it is a therapeutic option often considered in patients not eligible to or recurring after other local therapies. Liver SBRT can be delivered using a wide range of techniques and linear accelerators. We report the first evaluation for HCC of SBRT using volumetric modulated arc therapy (VMAT) and real-time adaptive tumor gating, which is a mainly completely non-invasive procedure (no fiducial markers for 65.2% of the patients). Our study showed that this SBRT technique has very favorable outcomes with optimal local control and a low toxicity rate.

Abstract

Liver SBRT is a therapeutic option for the treatment of HCC in patients not eligible for other local therapies. We retrospectively report the outcomes of a cohort of consecutive patients treated with SBRT for HCC at the Montpellier Cancer Institute. Between March 2013 and December 2018, 66 patients were treated with image-guided liver SBRT using VMAT and real-time adaptive tumor gating in our institute. The main endpoints considered in this study were local control, disease-free survival, overall survival, and toxicity. The median follow-up was 16.8 months. About 66.7% had prior liver treatment. Most patients received 50 Gy in five fractions of 10 Gy. No patient had local recurrence. Overall survival and disease-free survival were, respectively, 83.9% and 46.7% at one year. In multivariate analysis, the diameter of the lesions was a significant prognostic factor associated with disease-free survival (HR = 2.57 (1.19–5.53) p = 0.02). Regarding overall survival, the volume of PTV was associated with lower overall survival (HR = 2.84 (1.14–7.08) p = 0.025). No grade 3 toxicity was observed. One patient developed a grade 4 gastric ulcer, despite the dose constraints being respected. Image-guided liver SBRT with VMAT is an effective and safe treatment in patients with inoperable HCC, even in heavily pre-treated patients. Further prospective evaluation will help to clarify the role of SBRT in the management of HCC patients.

Toward MR-integrated proton therapy: modeling the potential benefits for liver tumors

Magnetic resonance imaging (MRI)-integrated proton therapy (MRiPT) is envisioned to improve treatment quality for many cancer patients. However, given the availability of alternative image-guided strategies, its clinical need is yet to be justified. This study aims to compare the expected clinical outcomes of MRiPT with standard of practice cone-beam CT (CBCT)-guided PT, and other MR-guided methods, i.e. offline MR-guided PT and MR-linac, for treatment of liver tumors. Clinical outcomes were assessed by quantifying the dosimetric and biological impact of target margin reduction enabled by each image-guided approach. Planning target volume (PTV) margins were calculated using random and systematic setup, delineation and motion uncertainties, which were quantified by analyzing longitudinal MRI data for 10 patients with liver tumors. Proton treatment plans were created using appropriate PTV margins for each image-guided PT method. Photon plans with margins equivalent to MRiPT were generated to represent MR-linac. Normal tissue complication probabilities (NTCP) of the uninvolved liver were compared. We found that PTV margin can be reduced by 20% and 40% for offline MR-guided PT and MRiPT, respectively, compared with CBCT-guided PT. Furthermore, clinical target volume expansion could be largely alleviated when delineating on MRI rather than CT. Dosimetric implications included decreased equivalent mean dose of the uninvolved liver, i.e. up to 24.4 Gy and 27.3 Gy for offline MR-guided PT and MRiPT compared to CBCT-guided PT, respectively. Considering Child-Pugh score increase as endpoint, NTCP of the uninvolved liver was significantly decreased for MRiPT compared to CBCT-guided PT (up to 48.4%,p < 0.01), offline MR-guided PT (up to 12.9%,p < 0.01) and MR-linac (up to 30.8%,p < 0.05). Target underdose was possible in the absence of MRI-guidance (D90 reduction up to 4.2 Gy in 20% of cases). In conclusion, MRiPT has the potential to significantly reduce healthy liver toxicities in patients with liver tumors. It is superior to other image-guided techniques currently available.

Overexpression of ADAM9 decreases radiosensitivity of hepatocellular carcinoma cell by activating autophagy

A disintegrin and a metalloprotease (ADAM)9 upregulated within human hepatocellular carcinoma (HCC) cells, but its effect on HCC radiosensitivity remains unknown. The present work aimed to examine the effect of ADAM9 on HCC radiosensitivity and to reveal its possible mechanism, which may be helpful in identifying a potential therapeutic strategy. Changes in ADAM9 expression after X-ray irradiation were identified using western blot, qRT-PCR, and immunofluorescence. ADAM9 stable knockdown and overexpression cell lines were constructed using lentivirus packaging. The radiosensitivity of HCC cells with altered ADAM9 expression was examined by CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays. This study also determined how autophagy affected HCC cell radiosensitivity. Furthermore, ADAM9, p62 and Bax expressions in HCC tissues that were removed after radiotherapy were detected by immunohistochemistry, and the relationship among the levels of these molecules was statistically analyzed. The level of ADAM9expression in HCC cells increased after X-ray irradiation. Through CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays, this work discovered the increased MHCC97H cell radiosensitivity after ADAM9 knockdown, and the radiosensitivity of Huh7 cells decreased after the overexpression of ADAM9. Furthermore, ADAM9 induced HCC cell autophagy via downregulating Nrf2 expression, while autophagy inhibition or induction reversed the effects of altered ADAM9 expression on radiosensitivity. Moreover, ADAM9 level showed a negative correlation with Bax and p62 expression within HCC tissues after radiotherapy. Taken together, ADAM9 decreased the radiosensitivity of HCC cells, and autophagy mediated this process.

Radiation-induced liver injury and hepatocyte senescence

Radiation-induced liver injury (RILI) is a major complication of radiotherapy during treatment for liver cancer and other upper abdominal malignant tumors that has poor pharmacological therapeutic options. A series of pathological changes can be induced by radiation. However, the underlying mechanism of RILI remains unclear. Radiation can induce cell damage via direct energy deposition or reactive free radical generation. Cellular senescence can be observed due to the DNA damage response (DDR) caused by radiation. The senescence-associated secretory phenotype (SASP) secreted from senescent cells can cause chronic inflammation and aggravate liver dysfunction for a long time. Oxidative stress further activates the signaling pathway of the inflammatory response and affects cellular metabolism. miRNAs clearly have differential expression after radiation treatment and take part in RILI development. This review aims to systematically profile the overall mechanism of RILI and the effects of radiation on hepatocyte senescence, laying foundations for the development of new therapies.

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.

Concurrent Sorafenib and Radiotherapy versus Radiotherapy Alone for Locally Advanced Hepatocellular Carcinoma: A Propensity-Matched Analysis

Purpose

Evidence is lacking concerning the benefit of the combination of sorafenib and radiotherapy to treat advanced hepatocellular carcinoma (HCC). To date, no publication has reported the outcomes of radiotherapy alone versus concurrent therapy. We aimed to compare the effectiveness of radiotherapy alone versus concurrent radiotherapy and sorafenib for locally advanced hepatocellular carcinoma.

Materials and Methods

We conducted a propensity score matching (PSM) cohort study comparing the effectiveness of the concurrent use of sorafenib and external beam radiotherapy versus radiotherapy alone in Barcelona Clinic Liver Cancer (BCLC) stage B or C, nonsurgically managed, nonmetastatic patients with HCC. Two subpopulations were matched based on baseline characteristics. Stratified analysis was also performed to assess the heterogeneous effects of the two arms. Overall survival (OS) was compared. Radiation-induced liver disease (RILD) and overt gastrointestinal (GI) bleeding events were also recorded.

Results

Seven hundred thirty-one BCLC stage B or C nonmetastatic HCC patients were identified from 2007 to 2017. Of these, 347 patients met the inclusion criteria (Radiotherapy alone: 269 patients; concurrent therapy: 78 patients). Propensity score matching yielded 73 patients each in the radiotherapy and concurrent groups. The median OS was 9.6 months in the radiotherapy-alone group and 9.9 months in the concurrent group (hazard ratio (HR): 1.12; 95% CI=0.78–1.62; p=0.544). Posttreatment toxicities, including radiation-induced liver disease and overt gastrointestinal bleeding, showed no significant differences between the groups.

Conclusion

In our study, the concurrent use of sorafenib and conventional external beam radiotherapy shows no survival benefit over radiotherapy alone for locally advanced hepatocellular carcinoma.

Accurate non-tumoral 99mTc-MAA absorbed dose prediction to plan optimized activities in liver radioembolization using resin microspheres

AIM

The manufacturers' recommended methods to calculate delivered activities in liver radioembolization are simplistic and only slightly personalized. Activity planning could also be based on a ^99mTc-macroaggregated albumin SPECT/CT (MAA) using the partition model but its accuracy is controversial. This study evaluates the dose parameters in the normal liver and in the tumor compartments using MAA SPECT/CT (pre-therapeutic imaging) and ⁹⁰Y TOF-PET/CT (post-therapy imaging). Finally, we propose a prescription of the activity as a function of the normal liver MAA distribution.

METHOD

66 procedures of RE (with resin microspheres) corresponding to 171 lesions were analyzed. Tumor to normal targeted liver uptake (T/NTL), tumor absorbed dose (TD) and whole normal liver absorbed (WNLD) were assessed with MAA and ⁹⁰Y imaging. Secondly, activities were recalculated using the MAA distribution in the normal liver compartment to reach the maximal tolerable liver dose. These Activities were compared to activities defined with the BSA method.

RESULTS

Compared to ⁹⁰Y imaging, our study demonstrated an accurate estimation of the WNLD using MAA imaging (Pearson's R = 0.97, p < 0.001). On the contrary, significant variations were found for TD (R = 0.65, p < 0.001). The MAA T/NTL ratio has a 85% positive predictive value in identifying patients who will get a ⁹⁰Y T/NTL ratio above 1.5. Moreover, activities calculated using the MAA distribution in the normal liver compartment were significantly higher to activities defined with the BSA method.

CONCLUSION

Whole normal liver absorbed doses are accurately predicted with MAA imaging and could be used to optimize the activity planning.

Comparison of Y-90 and Ho-166 Dosimetry Using Liver Phantom: A Monte Carlo Study

BACKGROUND

It is estimated that more than 1 million people are diagnosed with liver malignancy each year and one of the treatments is radioembolization with Y-90 and Ho-166. <P> Objective: The aim of this study is to calculate the absorbed doses caused by Y-90 and Ho-166 in tumor and liver parenchyma using a phantom via Monte Carlo method. <P> Methods: A liver model phantom including a tumor imitation of sphere (r =1.5cm) was defined in GATE. The total activity of 40 mCi Y-90 and Ho-166 was prescribed into tumor imitation as source and 2x2x2 mm3 voxel-sized DoseActors were identified at 30 locations. The simulation, performed to calculate the absorbed doses left by particles during 1 second for Y-90 and Ho-166, was run for a total of 10 days and 11 days, respectively. Total doses were calculated by taking the doses occurring in 1 second as a reference. <P> Results: The maximum absorbed doses were found to be 2.334E+03±1.576E+01 Gy for Y-90 and 7.006E+02±6.013E-01 Gy for Ho-166 at the center of tumor imitation. The minimum absorbed doses were found to be 2.133E-03±1.883E-01 Gy for Y-90 and 1.152E-02±1.036E-03 Gy for Ho-166 at the farthest location from source. The mean absorbed doses in tumor imitation were found to be 1.50E+03±1.36E+00 Gy and 4.58E+02±4.75E-01 Gy for Y-90 and Ho-166, respectively. And, the mean absorbed doses in normal parenchymal tissue were found to be2.07E+01±9.58E-02 Gy and 3.79E+00±2.63E-02 Gy for Y-90 and Ho-166, respectively. <P> Conclusion: Based on the results, Ho-166 is a good alternative to Y-90 according to dosimetric evaluation.

Unrecognized digestive toxicities of radiation therapy

The aim of this article is to review unrecognized toxicities resulting from radiation therapy of digestive neoplasms. Due to their precocious occurrence, acute toxicities are well-known by radiation oncologist, and their treatment well-established. Thus, acute toxicities will not be described in this review. We will focus on incidence, diagnosis, and management of late and uncommon toxicities occurring in the digestive tract and digestive organs. Prevention, by respecting healthy tissues constraints, is the main tool to reduce incidence of those rare complications. Nonetheless, once installed, late toxicities remain a major burden in terms of quality of life and can even be life threatening. Hence, information and education about their diagnosis and management is important.

Recent update on comprehensive therapy for advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The treatment methods for HCC are diverse, mainly including surgical resection, ablation, and liver transplantation. The curative effect can be achieved only for early stage HCC, and it is easy to recur and metastasize after surgery, with a 5-year recurrence rate as high as 70%. Most patients with HCC are in the middle and advanced stage at the time of diagnosis and lose the chance of surgical resection. In recent years, with the in-depth study of the pathogenesis of HCC and the progress of medical science and technology, the systemic treatment of advanced HCC has made a breakthrough. At present, multidisciplinary comprehensive treatment including targeted therapy and immunotherapy has become an effective strategy and inevitable trend for the treatment of advanced HCC. Combined therapy has greatly improved the prognosis of HCC patients and opened up a new milestone in the treatment of this malignancy. In this article, we focus on the treatment progress of advanced HCC to further guide clinical practice.

Using the Diaphragm as a Tracking Surrogate in CyberKnife Synchrony Treatment

BACKGROUND In this study, we assessed the usefulness of diaphragm surrogate tracking in the design of a respiratory model for CyberKnife Synchrony treatment of lung tumors. MATERIAL AND METHODS Twenty-four patients with lung cancer who underwent stereotactic body radiotherapy with CyberKnife between April and November 2019 were enrolled. Simulation plans for each patient were designed using Xsight lung tracking (XLT) and diaphragm tracking (DT) methods, and tumor visualization tests were performed. The offset consistency at each respiratory phase was analyzed. The relative distance along the alignment center of the superior-inferior (SI) axis in the 2 projections (dxAB), uncertainty (%), and average standard error (AvgStdErr)/maximum standard error (MAXStdErr) were also analyzed. RESULTS Bland-Altman analyses revealed that the average differences±standard deviation (SD) between XLT and DT tracking methods were 0.4±2.9 mm, 0.3±4.35 mm, and -1.8±6.8 mm for the SI, left-right (LR), and anterior-posterior (AP) directions, respectively. These results indicated high consistency in the SI and LR directions and poor consistency in the AP direction. Uncertainty differed significantly between XLT and DT (22.813±5.721% vs 9.384±3.799%; t=-5.236; P=0.0008), but we found no significant differences in dxAB, AvgStdErr, or MAXStdErr. CONCLUSIONS In the majority of cases, motion tracking by XLT and DT was consistent and synchronized in the SI directions, but not in the LR and AP directions. With a boundary margin of 0.3±4.35 mm and 1.8±6.8 mm for the LR and AP directions, DT may contribute to better implementation of CyberKnife Synchrony treatment in patients with lung tumors near the diaphragm that cannot be seen in tumor visualization tests.

Reducing the impact on renal function of kidney SABR through management of respiratory motion

PURPOSE

Stereotactic ablative body radiotherapy (SABR) is as a viable treatment option to treat kidney cancer. This study quantifies dose reduction to non-tumour ipsilateral kidney and estimated renal function gain from elimination of respiratory motion.

METHODS

We reviewed 62 previously treated kidney SABR patients. The gross tumour volume (GTV) was segmented in each phase of a four-dimensional CT (4DCT). Tumour motion amplitude (TMA) was obtained from the GTV centroid on each phase. Low modulation, motion managed (MM) plans were generated on the exhale phase image. Internal target volume (ITV)-based plans were generated on the 4DCT average intensity projection. To estimate delivered kidney dose, the ITV-based plan was copied ten times to the exhale phase image, with isocentre located at the GTV centroid position in each phase. The dose was calculated and averaged to result in non-motion managed plans. Difference in ipsilateral kidney volume receiving 50% of the prescription dose (V50%) and estimated glomerular filtration rate (GFR) change were compared between ITV and MM plans.

RESULTS

The mean ± st.dev. TMA was 0.79 ± 0.49 cm. Removing respiratory motion reduced ipsilateral kidney V50% (slope of the difference = 12 cc/cm of TMA, Pearson-r = 0.69, p-value <10^-9), and estimated GFR was improved (slope = 4.4 %/cm of TMA, Pearson-r = 0.85, p-value < 10^-10).

CONCLUSIONS

We have quantified the improvement in healthy kidney dose when removing respiratory motion from kidney SABR plans, and demonstrated an expected gain in GFR of 4.4 %/cm of motion removed.

Normal Tissue Injury Induced by Photon and Proton Therapies: Gaps and Opportunities

Despite technological advances in radiation therapy (RT) and cancer treatment, patients still experience adverse effects. Proton therapy (PT) has emerged as a valuable RT modality that can improve treatment outcomes. Normal tissue injury is an important determinant of the outcome; therefore, for this review, we analyzed 2 databases: (1) clinical trials registered with ClinicalTrials.gov and (2) the literature on PT in PubMed, which shows a steady increase in the number of publications. Most studies in PT registered with ClinicalTrials.gov with results available are nonrandomized early phase studies with a relatively small number of patients enrolled. From the larger database of nonrandomized trials, we listed adverse events in specific organs/sites among patients with cancer who are treated with photons and protons to identify critical issues. The present data demonstrate dosimetric advantages of PT with favorable toxicity profiles and form the basis for comparative randomized prospective trials. A comparative analysis of 3 recently completed randomized trials for normal tissue toxicities suggests that for early stage non-small cell lung cancer, no meaningful comparison could be made between stereotactic body RT and stereotactic body PT due to low accrual (NCT01511081). In addition, for locally advanced non-small cell lung cancer, a comparison of intensity modulated RTwith passive scattering PT (now largely replaced by spot-scanned intensity modulated PT), PT did not provide any benefit in normal tissue toxicity or locoregional failure over photon therapy. Finally, for locally advanced esophageal cancer, proton beam therapy provided a lower total toxicity burden but did not improve progression-free survival and quality of life (NCT01512589). The purpose of this review is to inform the limitations of current trials looking at protons and photons, considering that advances in technology, physics, and biology are a continuum, and to advocate for future trials geared toward accurate precision RT that need to be viewed as an iterative process in a defined path toward delivering optimal radiation treatment. A foundational understanding of the radiobiologic differences between protons and photons in tumor and normal tissue responses is fundamental to, and necessary for, determining the suitability of a given type of biologically optimized RT to a patient or cohort.

Treatment outcomes of stereotactic body radiation therapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinomas

AIM

To report the outcomes of stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinoma patients.

METHODS

From January 2005 to July 2018, 63 patients with 74 lesions with a maximum diameter ≤52 mm were treated by stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system. No patient with a Child-Pugh Score ≥9 was included, and 85.6% had a score of 5 or 6. Using the biological effective dose (BED) with an α/β ratio of 10 (BED₁₀ ), the median dose in BED₁₀ at the reference point was 76.8 Gy (range 60-122.5 Gy). Overall survival (OS) and local control rates were assessed using the Kaplan-Meier method.

RESULTS

With a median follow-up period of 24.6 months (range 0.9-118.4 months), the 1-year and 2-year OS rates were 86.8% (95% confidence interval [95% CI] 75.8-93.3) and 71.1% (57.8-81.6), respectively. The 2-year OS was 89.6% in patients with the baseline modified albumin-bilirubin (mALBI) grade =1, and 61.7% in patients with grade ≥2a. In the multivariate analysis, the mALBI grade (=1 vs. ≥2a) was a significant factor for OS (p = 0.028, 95% CI 1.11-6.18). The 1-year and 2-year local control rates were 100% (100-100%) and 92.0% (77.5-97.5%). The local control rates were significantly higher in the BED₁₀ ≥100 Gy group than in the BED₁₀ <100 Gy group (2-year 100% vs. 86.5%, p = 0.049) at the reference point.

CONCLUSION

This retrospective study of stereotactic body radiotherapy using real-time tumor-tracking radiotherapy for hepatocellular carcinoma showed favorable outcomes with lower incidence of toxicities, especially in patients treated with BED₁₀ ≥100 Gy to the reference point.

Therapies for hepatocellular carcinoma: overview, clinical indications, and comparative outcome evaluation. Part two: noncurative intention

Locoregional therapies can be offered to hepatocellular carcinoma patients as a bridge to transplant, to downstage disease burden for transplant eligibility, or for disease control to prolong survival. Systemic therapies also play a large role in HCC treatment, occasionally in conjunction with other methods. This manuscript reviews the various treatment options for HCC with a historically noncurative intent.

Efficacy and Prognostic Factors of Trans-Arterial Chemoembolization Combined With Stereotactic Body Radiation Therapy for BCLC Stage B Hepatocellular Carcinoma

Purpose

This study aimed to evaluate the efficacy and safety of trans-arterial chemoembolization (TACE) followed by stereotactic body radiation therapy (SBRT) in treating Barcelona Clinic Liver Cancer (BCLC) stage B hepatocellular carcinoma (HCC) not amenable to resection and radiofrequency ablation (RFA).

Methods

From February 2012 to January 2017, a total of 57 BCLC stage B HCC patients who were unsuitable candidates for resection and RFA treated with TACE combined with CyberKnife SBRT were included in this retrospective study. Patients underwent TACE for a median of two times (1-5 times) before SBRT. SBRT prescription doses ranged from 30 Gy to 50 Gy in 3-5 fractions.

Results

The median follow-up time was 42 months. The objective response rate (CR + PR) was 85.9%, and the disease control rate (CR + PR + SD) was 96.5%. The local control (LC) rates were 91.1% and 84.3% at 1 and 2 years, respectively. The 1-, 2-, 3-year overall survival (OS) and the median survival time were 73.2%, 51.4%, 32.4% and 26.6 months, respectively. The 1-, 2-, and 3-year progression-free survival (PFS) were 34.2%, 21.6%, and 9%, respectively, with a median PFS time of 9.7 months. A subgroup analysis was conducted in 32 patients with AFP ≥ 200 ng/ml before TACE. OS was significantly prolonged in those with AFP that decreased by more than 75% than those with AFP that decreased by less than 75% (P = 0.018) after SBRT. The treatment was well tolerated with only one patient (1.8%) developed grade 3 gastrointestinal toxicity, and another patient developed non-classical RILD. In multivariate analysis, tumor length ≥ 10 cm and AFP ≥ 200 ng/ml were independent poor prognostic factors for OS.

Conclusion

The combination of TACE and Cyberknife SBRT showed optimal efficacy with acceptable toxicity for BCLC stage B HCC.

The biological effects of radiation-induced liver damage and its natural protective medicine

The biological damage caused by the environmental factors such as radiation and its control methods are one of the frontiers of life science research that has received widespread attention. Ionizing radiation can directly interact with target molecules (such as DNA, proteins and lipids) or decomposed by radiation from water, leading to changes in oxidative events and biological activities in cells. Liver is a radiation-sensitive organ, and its radiosensitivity is second only to bone marrow, lymph, gastrointestinal tissue, gonads, embryos and kidneys. In addition, as a key organ of mammals, liver performs a series of functions, including the production of bile, the metabolism of nutrients, the elimination of waste, the storage of glycogen, and the synthesis of proteins. Therefore, liver is prone to various pathophysiological changes. In this review, the effects of radiation on liver injury, its pathogenesis, bystander effect and the natural traditional Chinese medicine to protect the radiation induced liver damage are discussed.

Radiofrequency ablation versus stereotactic body radiation therapy for small (≤ 3 cm) hepatocellular carcinoma: A retrospective comparison analysis

BACKGROUND AND AIM

We compared the clinical outcomes of radiofrequency ablation (RFA) and stereotactic body radiation therapy (SBRT) in small (≤ 3 cm) hepatocellular carcinoma.

METHODS

A total of 266 patients treated with RFA (n = 179) or SBRT (n = 87) were reviewed. Local control rates (LCRs), intrahepatic recurrence-free survival (IHRFS) rates, and overall survival (OS) rates were compared. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances in baseline characteristics between the two groups.

RESULTS

The median follow-up period was 50.3 months, and treatment method (RFA vs SBRT) was not a significant prognostic factor for LCR, OS, and IHRFS in both multivariate and IPTW-adjusted analyses. The 4-year LCRs after RFA and SBRT were 92.7% and 95.0%, respectively. Perivascular location was a significant prognostic factor for LCR in the entire patients and in the RFA group, but not in the SBRT group. The 4-year OS rates in the RFA and SBRT groups were 78.1% and 64.1%, respectively (P = 0.012). After IPTW adjustment, the 4-year LCRs (90.6% vs 96.3%) and OS rates (71.8% vs 70.2%) were not significantly different between the two groups. The rate of grade ≥ 3 adverse events was 0.6% (n = 1) in the RFA group and 1.1% (n = 1) in the SBRT group.

CONCLUSIONS

The two treatment methods showed comparable outcomes in terms of LCR, OS rate, and IHRFS rate after IPTW adjustment. SBRT seems to be a viable alternative method for small hepatocellular carcinomas that are not suitable for RFA due to tumor location.

Impact of adjuvant radiotherapy on biological and clinical parameters in right-sided breast cancer

PURPOSE

In patients with right-sided breast cancer (BC) the liver might be partially irradiated during adjuvant radiotherapy (RT). Thus, we performed a prospective observational study to evaluate the dose delivered to the liver, and its potential biological impact.

PATIENTS AND METHODS

We enrolled 34 patients with right-sided BC treated with adjuvant RT. The RT schedules were either the Canadian (42.5Gy in 16 fx) or standard fractionated (50Gy in 25 fx) regimen respectively with 9 (26.5%) and 25 (73.5%) patients each, ± a boost of 10-16Gy. Each patient had a complete blood count and liver enzymes analysis, before starting and during the last week of treatment.

RESULTS

A significant decrease in white blood cells and thrombocytes counts was observed during RT. We observed a significant correlation between certain hepatic parameters and the volume of the irradiated liver and/or the mean liver dose. A significant correlation between the volume of the right lung and the liver mean dose was found (P=0.008). In the bivariate analysis, a significant correlation between fatigue and the white blood cell count's evolution was observed (P<0.025).

CONCLUSION

With the standard RT technique, incidental irradiation of the liver was documented in a large number of patients, and some significant hepatic parameters alterations were observed, without an apparent clinical impact, but this study cannot exclude them. The liver mean dose was correlated with the right lung volume suggesting that deep inspiration breath hold (DIBH) techniques may represent a way to decrease the liver dose. These findings need to be evaluated in further larger studies.

Magnetic Resonance-Guided Stereotactic Body Radiotherapy of Liver Tumors: Initial Clinical Experience and Patient-Reported Outcomes

PURPOSE/OBJECTIVE

Stereotactic body radiation therapy (SBRT) has emerged as a valid treatment alternative for non-resectable liver metastases or hepatocellular carcinomas (HCC). Magnetic resonance (MR) guided SBRT has a high potential of further improving treatment quality, allowing for higher, tumoricidal irradiation doses whilst simultaneously sparing organs at risk. However, data on treatment outcome and patient acceptance is still limited.

MATERIAL/METHODS

We performed a subgroup analysis of an ongoing prospective observational study comprising patients with liver metastases or HCC. Patients were treated with ablative MR-guided SBRT at the MRIdian Linac in the Department of Radiation Oncology at Heidelberg University Hospital between January 2019 and February 2020. Local control (LC) and overall survival (OS) analysis was performed using the Kaplan-Meier method. An in-house designed patient-reported outcome questionnaire was used to measure patients' experience with the MR-Linac treatment. Toxicity was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE v. 5.0).

RESULTS

Twenty patients (with n = 18 metastases; n = 2 HCC) received MR-guided SBRT for in total 26 malignant liver lesions. Median biologically effective dose (BED at α/β = 10) was 105.0 Gy (range: 67.2-112.5 Gy) and median planning target volume was 57.20 ml (range: 17.4-445.0 ml). Median treatment time was 39.0 min (range: 26.0-67.0 min). At 1-year, LC was 88.1% and OS was 84.0%. Grade I° gastrointestinal toxicity °occurred in 30.0% and grade II° in 5.0% of the patients with no grade III° or higher toxicity. Overall treatment experience was rated positively, with items scoring MR-Linac staff's performance and items concerning the breath hold process being among the top positively rated elements. Worst scored items were treatment duration, positioning and low temperature.

CONCLUSION

MR-guided SBRT of liver tumors is a well-tolerated and well-accepted treatment modality. Initial results are promising with excellent local control and only mildest toxicity. However, prospective studies are warranted to truly assess the potential of MR-guided liver SBRT and to identify which patients profit most from this new versatile technology.

[Radiation therapy of hepatic haemangiomas: Review from a case report]

Haemangioma is the most frequent benign hepatic tumour. Haemangioma is generally asymptomatic but it can sometimes cause disabling symptoms depending on its size and location. Surgery and interventional radiology are the cornerstone of the treatment in this situation. Radiation therapy, already used with good efficacy and safety to treat hepatic malignant lesions as hepatocarcinoma and metastases, is a relevant option in case of contraindication to surgery because of multiple or very large lesions. In this context, we report the case of a patient presenting with multiple symptomatic hepatic haemangiomas, successfully treated by radiation therapy in our department. These good results justified a review of the literature to report series of patients treated in this indication and to describe the main treatment regimens used.

Assessment of the confidence interval in the multivariable normal tissue complication probability model for predicting radiation-induced liver disease in primary liver cancer

We developed a confidence interval-(CI) assessing model in multivariable normal tissue complication probability (NTCP) modeling for predicting radiation-induced liver disease (RILD) in primary liver cancer patients using clinical and dosimetric data. Both the mean NTCP and difference in the mean NTCP (ΔNTCP) between two treatment plans of different radiotherapy modalities were further evaluated and their CIs were assessed. Clinical data were retrospectively reviewed in 322 patients with hepatocellular carcinoma (n = 215) and intrahepatic cholangiocarcinoma (n = 107) treated with photon therapy. Dose-volume histograms of normal liver were reduced to mean liver dose (MLD) based on the fraction size-adjusted equivalent uniform dose. The most predictive variables were used to build the model based on multivariable logistic regression analysis with bootstrapping. Internal validation was performed using the cross-validation leave-one-out method. Both the mean NTCP and the mean ΔNTCP with 95% CIs were calculated from computationally generated multivariate random sets of NTCP model parameters using variance-covariance matrix information. RILD occurred in 108/322 patients (33.5%). The NTCP model with three clinical and one dosimetric parameter (tumor type, Child-Pugh class, hepatitis infection status and MLD) was most predictive, with an area under the receiver operative characteristics curve (AUC) of 0.79 (95% CI 0.74-0.84). In eight clinical subgroups based on the three clinical parameters, both the mean NTCP and the mean ΔNTCP with 95% CIs were able to be estimated computationally. The multivariable NTCP model with the assessment of 95% CIs has potential to improve the reliability of the NTCP model-based approach to select the appropriate radiotherapy modality for each patient.

Benefits of Local Treatment Including External Radiotherapy for Hepatocellular Carcinoma with Portal Invasion

We aimed to identify the oncologic benefits of local treatment including radiotherapy (LRT) in hepatocellular carcinoma (HCC) invading the portal vein. We used clinical data of patients with HCC invading the portal vein from 2008 to 2014 provided by 50 hospitals nationwide. A total of 1163 patients were included in the analysis. The LRT group was younger than the best supportive care (BSC) group (p < 0.001). The mean Child-Pugh score of the LRT group (6.1) was significantly lower than that of the BSC group (7.7) (p < 0.001). Propensity score-matched analysis generated 222 pairs. The median survival of all patients, LRT, and BSC groups were 5.0, 8.0, and 2.0 months, respectively. The overall survival (OS) rates in the LRT and BSC groups were 34.2% and 16.2% at one year, and 12.6% and 6.8% at two years, respectively (p < 0.001). Multivariate analysis showed that LRT (HR 0.41, 95% CI 0.32-0.52), age >60 years, extrahepatic metastases, tumor size ≥10 cm, and Child-Pugh class (CPC) B or C were independent predictors of higher mortality (all p < 0.05). Statistical differences in survival were maintained in all CPC-albumin-bilirubin classes (all p < 0.05). LRT was significant in patients with HCC with portal invasion, valid for patients with CPC A and B.

Stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of liver metastases in oligometastatic patients: initial clinical experience

Purpose

We aimed to present our initial clinical experience on the implementation of a stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of liver metastases in oligometastatic disease.

Materials and Methods

Twenty-one patients (24 lesions) with liver metastasis treated with SMART were included in this retrospective study. Step-and-shoot intensity-modulated radiotherapy technique was used with daily plan adaptation. During delivery, real-time imaging was used by acquiring planar magnetic resonance images in sagittal plane for monitoring and gating. Acute and late toxicities were recorded both during treatment and follow-up visits.

Results

The median follow-up time was 11.6 months (range, 2.2 to 24.6 months). The median delivered total dose was 50 Gy (range, 40 to 60 Gy); with a median fraction number of 5 (range, 3 to 8 fractions) and the median fraction dose was 10 Gy (range, 7.5 to 18 Gy). Ninety-three fractions (83.7%) among 111 fractions were re-optimized. No patients were lost to follow-up and all patients were alive except one at the time of analysis. All of the patients had either complete (80.9%) or partial (19.1%) response at irradiated sites. Estimated 1-year overall survival was 93.3%. Intrahepatic and extrahepatic progression-free survival was 89.7% and 73.5% at 1 year, respectively. There was no grade 3 or higher acute or late toxicities experienced during the treatment and follow-up course.

Conclusion

SMART represents a new, noninvasive and effective alternative to current ablative radiotherapy methods for treatment of liver metastases in oligometastatic disease with the advantages of better visualization of soft tissue, real-time tumor tracking and potentially reduced toxicity to organs at risk.

Personalized Image-Guided Therapies for Local Malignencies: Interdisciplinary Options for Interventional Radiology and Interventional Radiotherapy

Minimal-invasive interventions considerably extend the therapeutic spectrum in oncology and open new dimensions in terms of survival, tolerability and patient-friendliness. Through the influence of image-guided interventions, many interdisciplinary therapy concepts have significantly evolved, and this process is by far not yet over. The rapid progression of minimal-invasive technologies offers hope for new therapeutic concepts in the short, medium and long term. Image-guided hybrid-technologies complement and even replace in selected cases classic surgery. In this newly begun era of immune-oncology, interdisciplinary collaboration and the focus on individualized and patient-friendly therapies are crucial.