Stereotactic body radiotherapy for patients with unresectable primary hepatocellular carcinoma: dose-volumetric parameters predicting the hepatic complication

Prognostic nomogram of overall survival for radiation therapy in hepatocellular carcinoma: a population study based on the SEER database and an external cohort

Purpose

Radiotherapy (RT) plays an important role in the treatment of hepatocellular carcinoma (HCC). To screen patients who benefit most from RT, a nomogram for survival prediction of RT based on a large sample of patients with HCC was created and validated.

Methods

A total of 2,252 cases collected from the Surveillance, Epidemiology, and End Results (SEER) database were separated into a training or an internal validation cohort in a 7:3 ratio (n = 1,565:650). An external validation cohort of cases from our institute was obtained (n = 403). LASSO regression and Cox analyses were adopted to develop a nomogram for survival prediction. The decision curve analysis (DCA), calibration curve, and time-dependent receiver operating characteristic curves (TROCs) demonstrated the reliability of the predictive model.

Results

For patients with HCC who received RT, the analyses revealed that the independent survival prediction factors were T stage {T2 vs. T1, hazard ratio (HR) =1.452 [95% CI, 1.195-1.765], p < 0.001; T3 vs. T1, HR = 1.469 [95% CI, 1.168-1.846], p < 0.001; T4 vs. T1, HR = 1.291 [95% CI, 0.951-1.754], p = 0.101}, N stage (HR = 1.555 [95% CI, 1.338-1.805], p < 0.001), M stage (HR = 3.007 [95% CI, 2.645-3.418], p < 0.001), max tumor size (>2 and ≤5 vs. ≤2 cm, HR = 1.273 [95% CI, 0.992-1.633], p = 0.057; >5 and ≤10 vs. ≤2 cm, HR = 1.625 [95% CI, 1.246-2.118], p < 0.001; >10 vs. ≤2 cm, HR = 1.784 [95% CI, 1.335-2.385], p < 0.001), major vascular invasion (MVI) (HR = 1.454 [95% CI, 1.028-2.057], p = 0.034), alpha fetoprotein (AFP) (HR = 1.573 [95% CI, 1.315-1.882], p < 0.001), and chemotherapy (HR = 0.511 [95% CI, 0.454-0.576], p < 0.001). A nomogram constructed with these prognostic factors demonstrated outstanding predictive accuracy. The area under the curve (AUC) in the training cohort for predicting overall survival (OS) at 6, 12, 18, and 24 months was 0.824 (95% CI, 0.803-0.846), 0.824 (95% CI, 0.802-0.845), 0.816 (95% CI, 0.792-0.840), and 0.820 (95% CI, 0.794-0.846), respectively. The AUCs were similar in the other two cohorts. The DCA and calibration curve demonstrated the reliability of the predictive model.

Conclusion

For patients who have been treated with RT, a nomogram constructed with T stage, N stage, M stage, tumor size, MVI, AFP, and chemotherapy has good survival prediction ability.

Development and validation of a nomogram for radiation-induced hepatic toxicity after intensity modulated radiotherapy for hepatocellular carcinoma: a retrospective study

OBJECTIVE

This study aimed to construct a nomogram to predict radiation-induced hepatic toxicity in patients with hepatocellular carcinoma treated with intensity-modulated radiotherapy.

METHODS

This study reviewed the clinical characteristics and dose-volume parameters of 196 patients with hepatocellular carcinoma. Radiation-induced hepatic toxicity was defined as progression of the Child-Pugh score caused by intensity-modulated radiotherapy. Factors relevant to radiation-induced hepatic toxicity were selected using receiver operating characteristic and univariate logistic analysis. A risk assessment model was developed, and its discrimination was validated.

RESULTS

Eighty-eight (44.90%) and 28 (14.29%) patients had radiation-induced hepatic toxicity ≥ 1 (Child-Pugh ≥ 1) and radiation-induced hepatic toxicity ≥ 2 (Child-Pugh ≥ 2). Pre-treatment Child-Pugh, body mass index and dose-volume parameters were correlated with radiation-induced hepatic toxicity ≥ 1 using univariate logistic analysis. V15 had the best predictive effectiveness among the dose-volume parameters in both the training (area under the curve: 0.763, 95% confidence interval: 0.683-0.842, P < 0.001) and validation cohorts (area under the curve: 0.759, 95% confidence interval: 0.635-0.883, P < 0.001). The area under the curve values of the model that was constructed by pre-treatment Child-Pugh, body mass index and V15 for radiation-induced hepatic toxicity ≥1 were 0.799 (95% confidence interval: 0.719-0.878, P < 0.001) and 0.775 (95% confidence interval: 0.657-0.894, P < 0.001) in the training and validation cohorts, respectively. Patients with a body mass index ≤ 20.425, Barcelona clinic liver cancer = C, Hepatitis B Virus-positive, Eastern Cooperative Oncology Group = 1-2 and hepatic fibrosis require lower V15 dose limits.

CONCLUSIONS

Risk assessment model constructed from Pre-treatment Child-Pugh, V15 and body mass index can guide individualized patient selection of toxicity minimization strategies.

Role of Stereotactic Body Radiation Therapy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC)is a common type of liver cancer with a poor prognosis, especially in patients with advanced stages or underlying liver disease. While surgical resection, liver transplantation, and ablation therapies have traditionally been the mainstay of treatment for HCC, radiation therapy has become increasingly recognized as an effective alternative, particularly for those who are not surgical candidates. Stereotactic Body Radiation Therapy (SBRT) is a highly precise form of radiation therapy that delivers very high doses of radiation to the tumor while sparing surrounding healthy tissue. Several studies have reported favorable outcomes with SBRT in HCC treatment. Moreover, SBRT can be used to treat recurrent HCC after prior treatment, offering a potentially curative approach in select cases. While SBRT has demonstrated its efficacy and safety in treating HCC, future studies are needed to further investigate the potential role of SBRT in combination with other treatments for HCC.

Effectiveness of Robotic Stereotactic Radiotherapy in Patients Undergoing Re-irradiation: A Review

Stereotactic ablative radiotherapy (SABR) is a possible treatment option for patients who develop recurrence within or at the edge of a previously irradiated volume. Robotic stereotactic radiotherapy is the result of technological advances in robotic precision, real-time imaging, non-invasive, highly customizable treatment plan, and delivery with sub-millimeter accuracy. This article reviews the radiobiologic, technical, and clinical aspects of robotic-based SABR re-irradiation for various anatomical sites. An extensive literature search was performed to identify articles on the utilization of robotic stereotactic radiotherapy for patients undergoing re-irradiation. The reported prescription dose and fractionation data along with outcomes such as overall survival, local control rates, and toxicities were qualitatively reviewed. The findings consistently indicate that re-irradiation using robotic SABR provides encouraging survival rates with minimal toxicity in the clinical setting of various anatomical sites delivered using locally non-invasive means where other treatment options are scarce.

Non-classic radiation-induced liver disease after intensity-modulated radiotherapy for Child-Pugh grade B patients with locally advanced hepatocellular carcinoma

BACKGROUND

The incidence of classic radiation-induced liver disease (cRILD) has been significantly reduced. However, non-classic radiation-induced liver disease (ncRILD) remains a major concern following radiotherapy in patients with hepatocellular carcinoma (HCC). This study evaluated the incidence of ncRILD following intensity-modulated radiotherapy (IMRT) for Child-Pugh grade B (CP-B) patients with locally advanced HCC and established a nomogram for predicting ncRILD probability.

METHODS

Seventy-five CP-B patients with locally advanced HCC treated with IMRT between September 2014 and July 2021 were included. The max tumor size was 8.39 cm ± 5.06, and the median prescribed dose was 53.24 Gy ± 7.26. Treatment-related hepatotoxicity was evaluated within three months of completing IMRT. A nomogram model was formulated to predict the probability of ncRILD, using univariate and multivariate analysis.

RESULTS

Among CP-B patients with locally advanced HCC, ncRILD occurred in 17 (22.7%) patients. Two patients (2.7%) exhibited a transaminase elevation of ≥ G3, fourteen (18.7%) exhibited a Child-Pugh score increase of ≥ 2, and one (1.3%) demonstrated both a transaminase elevation of ≥ G3 and a Child-Pugh score increase of ≥ 2. No cRILD cases were observed. A mean dose to the normal liver of ≥ 15.1 Gy was used as the cutoff for ncRILD. Multivariate analysis revealed that the prothrombin time before IMRT, tumour number, and mean dose to the normal liver were independent risk factors for ncRILD. The nomogram established on the basis of these risk factors displayed exceptional predictive performance (AUC = 0.800, 95% CI 0.674-0.926).

CONCLUSIONS

The incidence of ncRILD following IMRT for CP-B patients with locally advanced HCC was acceptable. A nomogram based on prothrombin time before IMRT, tumour number, and mean dose to the normal liver accurately predicted the probability of ncRILD in these patients.

Surgical resection versus transarterial chemoembolization followed by moderately hypofractionated radiotherapy in hepatocellular carcinoma

BACKGROUND AND OBJECTIVE

Transarterial chemoembolization (TACE) is the gold standard treatment in intermediate hepatocellular carcinoma (HCC), but long-term disease control rates remain low. Herein, we compared results of TACE followed by hypofractionated radiotherapy (TACE-hRT) to surgical resection (SR) in early single or paucinodular intrahepatic HCC.

METHODS

Between June 2004 and November 2016, data on 160 consecutive patients with Barcelona Clinic Liver Cancer (BCLC) stage A Child-Pugh A HCC treated with SR or TACE-hRT in our expert center were retrospectively reviewed. Time to progression (TTP), progression-free survival (PFS), and overall survival (OS) were evaluated. Clinical outcomes were compared using the stabilized-weights inverse probability of treatment weighting propensity score.

RESULTS

Ninety-eight patients underwent SR and 62 were treated by TACE-hRT. Median total dose of RT was 54 Gy (interquartile range [IQR] 54-54) in 3‑Gy fractions. Median OS follow-up was 93 months. TTP did not significantly differ between patients following SR and TACE-hRT, with 1‑year rates of 68.2% and 82.6% (p = 0.17), respectively. In contrast, PFS and OS were lower in the TACE-hRT group (p = 0.015 and p = 0.006), with a median OS of 37 vs. 63 months for patients with surgery and TACE-hRT, respectively. In multivariate analysis, a significant negative impact on PFS and OS was seen for age at diagnosis, on TTP for alcohol-related liver disease, and on OS for total number of HCC nodules. Symptomatic grade ≥ 3 adverse events were presented by 42 (42.9%) SR and 19 (30.6%) TACE-hRT patients (p = 0.17).

CONCLUSION

In patients presenting Child-Pugh A BCLC‑A HCC with high risk for surgical complications, TACE-hRT can be an effective and safe treatment. However, surgical management remains the standard of care whenever possible.

Feasibility and dosimetric evaluation of single- and multi-isocentre stereotactic body radiation therapy for multiple liver metastases

Objectives

Single-isocentre volumetric-modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) improves treatment efficiency and patient compliance for patients with multiple liver metastases (MLM). However, the potential increase in dose spillage to normal liver tissue using a single-isocentre technique has not yet been studied. We comprehensively evaluated the quality of single- and multi-isocentre VMAT-SBRT for MLM and propose a RapidPlan-based automatic planning (AP) approach for MLM SBRT.

Methods

A total of 30 patients with MLM (two or three lesions) were selected for this retrospective study. We manually replanned all patients treated with MLM SBRT by using the single-isocentre (MUS) and multi-isocentre (MUM) techniques. Then, we randomly selected 20 MUS and MUM plans for training to generate the single-isocentre RapidPlan model (RPS) and the multi-isocentre RapidPlan model (RPM). Finally, we used data from the remaining 10 patients to validate RPS and RPM.

Results

Compared with MUS, MUM reduced the mean dose delivered to the right kidney by 0.3 Gy. The mean liver dose (MLD) was 2.3 Gy higher for MUS compared with MUM. However, the monitor units, delivery time, and V20Gy of normal liver (liver-gross tumour volume) for MUM were significantly higher than for MUS. Based on validation, RPS and RPM slightly improved the MLD, V20Gy, normal tissue complications, and dose sparing to the right and left kidneys and spinal cord compared with manual plans (MUS vs RPS and MUM vs RPM), but RPS and RPM significantly increased monitor units and delivery time.

Conclusions

The single-isocentre VMAT-SBRT approach could be used for MLM to reduce treatment time and patient comfort at the cost of a small increase in the MLD. Compared with the manual plans, RapidPlan-based plans, especially RPS, have slightly improved quality.

Stereotactic Ablative Body Radiotherapy as a Bridge to Liver Transplant for Hepatocellular Carcinoma: Preliminary Results of Başkent University Experience

OBJECTIVES

Hepatocellular carcinoma is the most common primary liver tumor, with curative treatment options being liver transplant and resection. However, approximately 20% to 30% of patients have substantial disease progression while awaiting transplant. Here, we report our initial experience on stereotactic ablative body radiotherapy as a bridge to liver transplant for patients with hepatocellular carcinoma.

MATERIALS AND METHODS

Seven patients with 9 lesions received stereotactic ablative body radiotherapy as a bridge treatment to transplant. All patients underwent radiofrequency ablation, transcatheter arterial chemoembolization, or hepatic resection before stereotactic ablative body radiotherapy. Magnetic resonance imaging was used to evaluate radiographic responses 1 month later.

RESULTS

Median age of patients was 65 years (range, 63-71 years), median stereotactic ablative body radiotherapy dose was 45 Gy (range, 30-54 Gy; delivered in 3-5 fractions), and median tumor diameter was 17 mm (range, 12-30 mm). Before stereotactic ablative body radiotherapy, all patients underwent liver-directed therapies, including transcatheter arterial chemoembolization for 3 lesions, transcatheter arterial chemoembolization and radiofrequency ablation for 4 lesions, surgical resection for 1 lesion, and surgical resection plus transcatheter arterial chemoembolization for the remaining lesion. Patients showed no evidence of gastrointestinal toxicity or radiation-induced liver disease. Acute toxicity was negligible; all patients completed the treatment course. One month after stereotactic ablative body radiotherapy administration, response rates were assessed with magnetic resonance imaging, with complete responses obtained in 5 lesions (55.5%), partial responses for 2 lesions, and stable disease for 2 lesions. No disease progression was shown following stereotactic ablative body radiotherapy application.

CONCLUSIONS

Stereotactic ablative body radiotherapy is an effective, safe, and tolerable bridging therapy option. Although we observed an early response after treatment, exact response rates will not be known for at least 3 months following stereotactic ablative body radiotherapy. Thus, our findings should be confirmed through additional prospective studies with longer follow-up.

Clinical Values and Markers of Radiation-Induced Liver Disease for Hepatocellular Carcinoma With Portal Vein Tumor Thrombus Treated With Stereotactic Body Radiotherapy

Background

Information about radiation-induced liver disease (RILD) in hepatocellular carcinoma (HCC) patients preexisting hepatitis B cirrhosis with portal vein tumor thrombus (PVTT) extended to the main portal vein treated with stereotactic body radiotherapy (SBRT) is still inadequate and the predictive markers for RILD have not been cleared in these patients. The aim of the study is to identify factors that can be used to predict RILD and to evaluate the influence of RILD in these patients.

Methods

In our study, 59 patients were analyzed and evaluated from December 2015 to June 2019, according to the entry criteria. After treatment, 59 patients were followed up within the first month and then every 3 months. Hematology test, tumor markers, three-phasic CT scan of the lungs, and CT or MRI scan of the liver were performed at each follow up.

Results

Median overall survival time was 10.7 months (range, 5.8 to 14.9). RILD appeared in 17 of the 59 patients (28.8%) at the 3rd month after SBRT. In the univariate analysis, not only the CP score class (A or B) but also each different pretreatment CP score (p < 0.05) was a significant predictive factor of RILD. More RILD cases were detected with the increase of CP score. The recovery rate decreased as the baseline CP score increased (p < 0.05). It was found that the overall survival time was affected by only baseline CP score and RILD (p < 0.05).

Conclusions

The development of RILD has a dependency on the CP score in these patients. CP scores before treatment and RILD are significantly associated with overall survival. SBRT is an effective and safe method for patients with CP ≤ B7. For patients with CP-B8, liver function should be monitored more frequently. It is not safe enough for the SBRT treatment in CP-B9 patients.

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.

Stereotactic Body Radiation Therapy after Chemotherapy for Unresectable Perihilar Cholangiocarcinoma: The STRONG Trial, a Phase I Safety and Feasibility Study

Simple Summary

The role of radiotherapy in the treatment of perihilar cholangiocarcinoma has not yet been properly defined. In this prospective study, we therefore explored the addition to first-line chemotherapy of stereotactic body radiation therapy (SBRT) delivered in 15 fractions. Patients eligible for the study had been diagnosed with unresectable perihilar cholangiocarcinoma, and then had no progressive disease after completing treatment with 6–8 cycles of cisplatin-gemcitabine. Primary endpoints were feasibility and safety. Secondary endpoints were local control, progression-free survival, overall survival, and quality of life. As each patient completed the SBRT successfully and no dose-limiting toxicity was found, we consider this treatment to be both feasible and safe. The local control rate and overall survival were promising. However, due to the small sample size of this study, we urge the analysis of this treatment in a larger series of patients.

Abstract

Background: In unresectable pCCA, the standard of care is palliative chemotherapy. We investigated the feasibility and safety of adding stereotactic body radiation therapy (SBRT) after chemotherapy. Methods: Patients with unresectable pCCA, stage T1-T4N0-N1M0, ECOG 0-1, having finished 6–8 cycles of cisplatin and gemcitabine without disease progression were eligible. SBRT was planned in 15 fractions of 3.0–4.5 Gy. The primary endpoints were feasibility (defined as completing SBRT as planned) and toxicity, evaluated within 3 months after SBRT (CTCAE v4.03). A conventional “3 + 3” design was used, corresponding to a sample size of 6 patients. Dose-limiting toxicity (DLT) was defined as grade ≥ 4 hepatobiliary or grade ≥ 3 gastrointestinal toxicity. The secondary endpoints, measured from the start of radiotherapy, were local control, progression-free survival, overall survival, and quality of life (QoL). ClinicalTrials.gov identifier: NCT03307538. Results: Six patients were enrolled between November 2017 and March 2020. SBRT was delivered as planned. All patients were treated with 60Gy (15 × 4.0Gy). No SBRT-related DLT was observed. The most common grade ≥ 3 toxicity was cholangitis (n = 5). The median follow-up was 14 months. The 12-month local control rate was 80%. We observed no substantial changes in QoL. Conclusion: In patients with unresectable pCCA with stable disease after palliative chemotherapy, adding SBRT is feasible and safe. The observed local control merits an additional evaluation of effectiveness.

Feasibility and Early Clinical Experience of Online Adaptive MR-Guided Radiotherapy of Liver Tumors

PURPOSE

To assess the feasibility and early results of online adaptive MR-guided radiotherapy (oMRgRT) of liver tumors.

METHODS

We retrospectively examined consecutive patients with primary or secondary liver lesions treated at our institution using a 0.35T hybrid MR-Linac (Viewray Inc., Mountain View, CA, USA). Online-adaptive treatment planning was used to account for interfractional anatomical changes, and real-time intrafractional motion management using online 2D cine MRI was performed using a respiratory gating approach. Treatment response and toxicity were assessed during follow-up.

RESULTS

Eleven patients and a total of 15 lesions were evaluated. Histologies included cholangiocarcinomas and metastases of neuroendocrine tumors, colorectal carcinomas, sarcomas and a gastrointestinal stroma tumor. The median BED₁₀ of the PTV prescription doses was 84.4 Gy (range 59.5-112.5 Gy) applied in 3-5 fractions and the mean GTV BED₁₀ was in median 147.9 Gy (range 71.7-200.5 Gy). Online plan adaptation was performed in 98% of fractions. The median overall treatment duration was 53 min. The treatment was feasible and successfully completed in all patients. After a median follow-up of five months, no local failure occurred and no ≥ grade two toxicity was observed. OMRgRT resulted in better PTV coverage and fewer OAR constraint violations.

CONCLUSION

Early results of MR-linac based oMRgRT for the primary and secondary liver tumors are promising. The treatment was feasible in all cases and well tolerated with minimal toxicity. The technique should be compared to conventional SBRT in further studies to assess the advantages of the technique.

Carbon ion radiotherapy for patients with hepatocellular carcinoma in the caudate lobe carbon ion radiotherapy for hepatocellular carcinoma in caudate lobe

AIM

The treatment of hepatocellular carcinoma in the caudate lobe (HCCCL) is technically challenging. We aimed to investigate the efficacy and toxicity of carbon ion radiotherapy (C-ion RT) for HCCCL.

METHODS

Patients with HCCCL treated with C-ion RT at our hospital between January 2011 and December 2018 were evaluated. The total dose was 52.8 or 60 Gy (relative biological effectiveness) in four or 12 fractions depending on the distance between the tumor and the gastrointestinal tract. The survival outcome, the presence or absence of recurrence (local recurrence, intrahepatic recurrence outside the irradiation field, or extrahepatic recurrence), and acute/late adverse events were evaluated.

RESULTS

Nine patients were included. The median tumor size was 3.4 cm, and the median follow-up duration was 18.3 months for all patients. No patient developed local recurrence during follow-up. Five patients subsequently developed intrahepatic recurrence outside the irradiation field and two had extrahepatic metastasis. Five patients died of hepatocellular carcinoma. No acute adverse events of grade ≥2 were observed. Two patients experienced grade 2 or 3 late adverse events, including obstructive jaundice, hepatic encephalopathy, ascites, and edema.

CONCLUSION

Carbon ion radiotherapy for HCCCL achieved excellent local control with acceptable adverse events and can thus be a curative treatment option for HCCCL.

Capacity of proton beams in preserving normal liver tissue during proton beam therapy for hepatocellular carcinoma

Unirradiated liver volume (ULV) preservation rate is an important factor associated with radiation-induced liver disease (RILD) in patients with hepatocellular carcinoma (HCC) undergoing proton beam therapy (PBT). The purpose of this study is to identify the predictors for ULV preservation and quantify the capacity of proton beams in normal liver sparing during PBT. We reviewed planning data of 92 patients with single intrahepatic HCC tumors undergoing PBT. The potential clinical and planning factors that may affect ULV preservation were involved in multiple linear regression for ULV preservation rate. The significant factors were determined to be predictors and their influences were quantified. The median ULV preservation rate was 62.08%. All the assessed clinical factors showed significant effects on ULV preservation rate: clinical target volume (CTV), P < 0.001; portal vein tumor thrombosis (PVTT), P = 0.010; left lobe tumor, P = 0.010. In contrast, none of the planning factors demonstrated significance. The coefficients of significant factors in multiple linear regression were 60.85 for intercept, -0.02 for CTV, -9.01 for PVTT and 8.31 for left lobe tumors. The capacity of proton beams to spare normal liver tissue during PBT for HCC is mainly affected by clinical factors. The baseline of the ULV preservation rate is 60.85%, decreasing 0.02% with each milliliter of CTV increase and 9.01% for tumors with PVTT, and increasing 8.31% for tumors limited to the left lobe. Further clinical studies should be carried out to correlate our dosimetric findings with clinical outcomes.

Radiation-induced liver disease in the era of SBRT: a review

INTRODUCTION

Stereotactic Body Radiotherapy (SBRT) in liver tumors allows ablative radiation doses in tumors preserving the liver tissue. However, liver is a parallel organ allowing high doses in a small region to preserve its function. If this is not possible, radio-induced liver toxicity is produced. Radio-induced liver toxicity or radio-induced liver disease (RILD) is the most serious toxicity in liver radiotherapy.

AREAS COVERED

In this review, we analyzed published literature on PubMed and MEDLINE. We included papers in English language with information about RILD characteristics, diagnostic, risk factors, pathophysiology, and treatment. All citations were evaluated for relevant content and validation.

EXPERT OPINION

The study of RILD is fundamental before the implementation of liver SBRT. Radio-induced liver toxicity is a complication that can be fatal for patients. This is a diagnosis of exclusion and it is essential that experts in the treatment of hepatic SBRT know about it and anticipate its development. The study and development of molecular or imaging biomarkers could be key in their diagnosis and prevention.

MRI-guided adaptive radiotherapy for liver tumours: visualising the future

MRI-guided radiotherapy is a novel and rapidly evolving technology that might enhance the risk-benefit ratio. Through direct visualisation of the tumour and the nearby healthy tissues, the radiation oncologist can deliver highly accurate treatment even to mobile targets. Each individual treatment can be customised to changing anatomy, potentially reducing the risk of radiation-related toxicities while simultaneously increasing the dose delivered to the tumour. MRI-guided radiotherapy offers a new tool for the radiation oncologist, and creates an opportunity to achieve durable local control of liver tumours that might not otherwise be possible. Future work will allow us to expand the population eligible for curative-intent radiotherapy, optimise and customise radiation doses to specific tumours, and hopefully create opportunities for improving outcomes through machine learning and radiomics-based approaches. This Review outlines the current and future applications for MRI-guided radiotherapy with respect to metastatic and primary liver cancers.

Stereotactic ablative radiotherapy for colorectal cancer liver metastasis

Survival improvement of colorectal liver metastasis (CRLM) benefits from systemic therapy and metastasis-directed local therapy. Stereotactic ablative body radiotherapy (SABR), as a new efficient metastasis-directed local therapy with a systematic impact, plays a vital role in CRLM multidisciplinary treatment. SABR leads to a dramatic immunological change in the tumor microenvironment (TME) via differential activation of cytoprotective and cytotoxic pathways in malignant and non-malignant cells, in addition to direct tumor cell death. The synergy of SABR and immunotherapy might increase the abscopal response rate of out-field lesions by targeting different steps of the immune-mediated response, in addition to direct intratumoral cell death. The clinical treatment and efficacy of SABR, its influence on TME, and potential molecular underpinnings of which are the topic of this review.

Dosimetric Analysis and Normal-Tissue Complication Probability Modeling of Child-Pugh Score and Albumin-Bilirubin Grade Increase After Hepatic Irradiation

PURPOSE

This study aimed to develop robust normal-tissue complication probability (NTCP) models for patients with hepatocellular carcinoma treated with radiation therapy (RT) using Child-Pugh (CP) score and albumin-bilirubin (ALBI) grade increase as endpoints for hepatic toxicity.

METHODS AND MATERIALS

Data from 108 patients with hepatocellular carcinoma treated with RT between 2008 and 2017 were evaluated, of which 47 patients (44%) were treated with proton RT. Of these patients, 29 received stereotactic body RT and 79 moderately hypofractionated RT to median physical tumor doses of 43 Gy in 5 fractions and 59 Gy in 15 fractions, respectively. A generalized Lyman-Kutcher-Berman (LKB) model was used to model the NTCP using 2 clinical endpoints, both evaluated at 3 months after RT: CP score increase of ≥2 and ALBI grade increase of ≥1 from the pre-RT baseline. Confidence intervals on LKB fit parameters were determined using bootstrap resampling.

RESULTS

Compared with previous NTCP models, this study found a stronger correlation between normal liver volume receiving low doses of radiation (5-10 Gy) and a CP score or ALBI grade increase. A CP score increase exhibited a stronger correlation to normal liver volumes irradiated than an ALBI grade increase. LKB models for CP increase found values for the volume-effect parameter of a = 0.06 for all patients, and a = 0.02/0.09 when fit to photon/proton patients separately. Subset analyses for patients with superior initial liver functions showed consistent dose-volume effects (a = 0.1) and consistent dose-response relationships.

CONCLUSIONS

This study presents an update of liver NTCP models in the era of modern RT techniques using relevant endpoints of hepatic toxicity, CP score and ALBI grade increase. The results show a stronger influence of low-dose bath on hepatic toxicity than those found in previous studies, indicating that RT techniques that minimize the low-dose bath may be beneficial for patients.

Characterization of robust optimization for VMAT plan for liver cancer

Purpose

We investigated the feasibility of robust optimization for volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) for liver cancer in comparison with planning target volume (PTV)-based optimized plans. Treatment plan quality, robustness, complexity, and accuracy of dose delivery were assessed.

Methods

Ten liver cancer patients were selected for this study. PTV-based optimized plans with an 8-mm PTV margin and robust optimized plans with an 8-mm setup uncertainty were generated. Plan perturbed doses were evaluated using a setup error of 8 mm in all directions from the isocenter. The dosimetric comparison parameters were clinical target volume (CTV) doses (D_98%, D_50%, and D_2%), liver doses, and monitor unit (MU). Plan complexity was evaluated using the modulation complexity score for VMAT (MCSv).

Results

There was no significant difference between the two optimizations with respect to CTV doses and MUs. Robust optimized plans had a higher liver dose than did PTV-based optimized plans. Plan perturbed dose evaluations showed that doses to the CTV for the robust optimized plans had small variations. Robust optimized plans were less complex than PTV-based optimized plans. Robust optimized plans had statistically significant fewer leaf position errors than did PTV-based optimized plans.

Conclusions

Comparison of treatment plan quality, robustness, and plan complexity of both optimizations showed that robust optimization could be feasibile for VMAT of liver cancer.

Stereotactic Body Radiotherapy for Large Unresectable Hepatocellular Carcinomas - A Single Institution Phase II Study

AIMS

To evaluate the safety and efficacy of liver stereotactic body radiotherapy (SBRT) in the treatment of unresectable hepatocellular carcinomas (HCC) measuring >5 cm.

MATERIALS AND METHODS

Between November 2013 and February 2016, 13 patients with unresectable HCC (>5 cm), ineligible for other local treatments, with a Child-Pugh score (CPS) ≤ B7, were enrolled into a single-institution phase II study. SBRT was delivered by volumetric-modulated arc radiotherapy. Radiological response was reported using modified Response Evaluation Criteria in Solid Tumours criteria and toxicities graded by Common Terminology Criteria for Adverse Events v4 criteria.

RESULTS

Sixteen hepatomas (median size 7.5 cm, range 5.1-9.7 cm) were treated in 13 patients. The baseline CPS was A5/6 in nine patients (69%) and B7 in four patients (31%). Five patients (38%) received previous liver-directed treatment. The median prescribed dose was 45 Gy (range 40-45 Gy) in five fractions. The median follow-up was 17.7 months. The 1-year local control rate was 92%. The median overall survival was 17.7 months and the 1-year overall survival was 62%. The median time to local progression was not reached. Five patients (39%) had an increase in CPS by two or more points at 3 months. Overall, there were 10 grade 3 acute toxicities occurring in seven patients, of which six were haematological. Quality of life remained clinically stable or improved at 3 months in 61.5% and 53.8% of patients based on the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 Global Health Score and Functional Assessment of Cancer Therapy - Hepatobiliary version 4 score, respectively.

CONCLUSIONS

In our cohort, SBRT to unresectable large HCC tumours provided excellent local control with acceptable toxicities. Regional recurrence remained the major cause of failure. Further studies are warranted to examine the role for SBRT in combination with other modalities to maximise disease control in the liver.

Stereotactic ablative radiotherapy versus conventionally fractionated radiotherapy in the treatment of hepatocellular carcinoma with portal vein invasion: a retrospective analysis

BACKGROUND

This study aimed to compare the clinical outcomes of stereotactic ablative radiotherapy (SABR) and conventionally fractionated radiotherapy (CFRT) in hepatocellular carcinoma (HCC) patients with portal vein invasion (PVI).

METHODS

HCC patients with PVI treated with radiotherapy from 2007 to 2016 were analysed. CFRT was administered at a median dose of 51.5 Gy (interquartile range, 45-54 Gy) with 1.8-3 Gy per fraction. SABR was administered at a median dose of 45 Gy (interquartile range, 40-48 Gy) with 6-12.5 Gy per fraction. Treatment efficacy, toxicity, and associated predictors were assessed.

RESULTS

Among the 104 evaluable patients (45 in the SABR group and 59 in the CFRT group), the overall response rate (ORR, complete and partial response) was significantly higher in the SABR group than the CFRT group (62.2% vs. 33.8%, p = 0.003). The 1-year overall survival (OS) rate (34.9% vs. 15.3%, p = 0.012) and in-field progression-free survival (IFPS) rate (69.6% vs. 32.2%, p = 0.007) were also significantly higher in the SABR vs. CFRT group. All 3 rates remained higher in the SABR group after propensity score matching. Multivariable analysis identified SABR and a biologically effective dose ≥65 Gy as favourable predicators of OS. There was no difference between treatment groups in the incidence of radiation-induced liver disease or increase of Child-Pugh score ≥ 2 within 3 months of radiotherapy.

CONCLUSIONS

SABR was superior to CFRT in terms of ORR, OS, and IFPS. We suggest that SABR should be the preferred technique for HCC patients with PVI.

Modeling of Normal Tissue Complications Using Imaging and Biomarkers After Radiation Therapy for Hepatocellular Carcinoma

PURPOSE

To develop normal tissue complications (NTCP) models for hepatocellular cancer (HCC) patients who undergo liver radiation therapy (RT) and to evaluate the potential role of functional imaging and measurement of blood-based circulating biological markers before and during RT to improve the performance of these models.

METHODS AND MATERIALS

The data from 192 HCC patients who had undergone RT from 2005 to 2014 were evaluated. Of the 192 patients, 146 had received stereotactic body RT (SBRT) and 46 had received conventional RT to a median physical tumor dose of 49.8 Gy and 50.4 Gy, respectively. The physical doses were converted into 2-Gy equivalents for analysis. Two approaches were investigated for modeling NTCP: (1) a generalized Lyman-Kutcher-Burman model; and (2) a generalization of the parallel architecture model. Three clinical endpoints were considered: the change in albumin-bilirubin (ALBI), change in Child-Pugh (C-P) score, and grade ≥3 liver enzymatic changes. Local dynamic contrast-enhanced magnetic resonance imaging portal venous perfusion information was used as an imaging biomarker for local liver function. Four candidate inflammatory cytokines were considered as biological markers. The imaging findings and cytokine levels were incorporated into NTCP modeling, and their role was evaluated using goodness-of-fit metrics.

RESULTS

Using dosimetric information only, the Lyman-Kutcher-Burman model for the ALBI/C-P change had a steeper response curve compared with grade ≥3 enzymatic changes. Incorporating portal venous perfusion imaging information into the parallel architecture model to represent functional reserve resulted in relatively steeper dose-response curves compared with dose-only models. A larger loss of perfusion function was needed for enzymatic changes compared with ALBI/C-P changes. Increased transforming growth factor-β1 and eotaxin expression increased the trend of expected risk in both NTCP modeling approaches but did not reach statistical significance.

CONCLUSIONS

The incorporation of imaging findings and biological markers into NTCP modeling of liver toxicity improved the estimates of expected NTCP risk compared with using dose-only models. In addition, such generalized NTCP models should contribute to a better understanding of the normal tissue response in HCC SBRT patients and facilitate personalized treatment.

SBRT for Hepatocellular Carcinoma: 8-Year Experience from a Regional Transplant Center

PURPOSE

The study aimed to evaluate stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) in patients not eligible for liver transplant (LT).

METHODS

We retrospectively identified transplant-ineligible HCC patients treated with SBRT to the liver between 2004 and 2013. Our primary endpoint was overall survival (OS). We also report treatment toxicities using CTCAE 3.0, radiographic response, and patterns of failure.

RESULTS

We identified 93 patients with median age at SBRT of 65.8 years. Forty-six percent were classified as Child-Pugh B or C and 85% had an Eastern Cooperative Oncology Group performance status of 1-2. After SBRT, 86% of patients experienced no or mild treatment-related adverse events. Only 8% of patients experienced grade 3 and 2% of patients experienced grade 4 adverse events. Overall radiographic response was complete in 1.2%, partial in 35.4%, stable in 43.9%, and progressive disease in 19.5%. Median OS was 8.8 months with 1-, 2-, and 3-year OS rates of 38.0, 29.8 and 21.2%, respectively. The Cancer of the Liver Italian Program (CLIP) score was found to strongly correlate with survival. Median OS for patients with CLIP scores of 0, 1, 2, and 3 was 21.1, 8.5, 5.1, and 7.1 months, respectively (p = 0.003).

CONCLUSION

Our series demonstrates that SBRT is generally safe for HCC patients, even those with advanced liver failure. Although survival is generally poor, we were able to identify a group of patients with good liver function and early tumor stage who can achieve median OS of close to 2 years with SBRT.

Protons versus Photons for Unresectable Hepatocellular Carcinoma: Liver Decompensation and Overall Survival

PURPOSE

Ablative radiation therapy is increasingly being used for hepatocellular carcinoma (HCC) resulting in excellent local control rates; however, patients without evidence of disease progression often die from liver failure. The clinical benefit of proton- over photon-based radiation therapy is unclear. We therefore sought to compare clinical outcomes of proton versus photon ablative radiation therapy in patients with unresectable HCC.

METHODS AND MATERIALS

This is a single-institution retrospective study of patients treated during 2008 to 2017 with nonmetastatic, unresectable HCC not previously treated with liver-directed radiation therapy and who did not receive further liver-directed radiation therapy within 12 months after completion of index treatment. The primary outcome, overall survival (OS), was assessed using Cox regression. Secondary endpoints included incidence of non-classic radiation-induced liver disease (defined as increase in baseline Child-Pugh score by ≥2 points at 3 months posttreatment), assessed using logistic regression, and locoregional recurrence, assessed using Fine-Gray regression for competing risks. All outcomes were measured from radiation start date.

RESULTS

The median follow-up was 14 months. Of 133 patients with median age 68 years and 75% male, 49 (37%) were treated with proton radiation therapy. Proton radiation therapy was associated with improved OS (adjusted hazard ratio, 0.47; P = .008; 95% confidence interval [CI], 0.27-0.82). The median OS for proton and photon patients was 31 and 14 months, respectively, and the 24-month OS for proton and photon patients was 59.1% and 28.6%, respectively. Proton radiation therapy was also associated with a decreased risk of non-classic radiation-induced liver disease (odds ratio, 0.26; P = .03; 95% CI, 0.08-0.86). Development of nonclassic RILD at 3 months was associated with worse OS (adjusted hazard ratio, 3.83; P < .001; 95% CI, 2.12-6.92). There was no difference in locoregional recurrence, including local failure, between protons and photons.

CONCLUSIONS

Proton radiation therapy was associated with improved survival, which may be driven by decreased incidence of posttreatment liver decompensation. Our findings support prospective investigations comparing proton versus photon ablative radiation therapy for HCC.

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: Current Trends and Controversies

Hepatocellular carcinoma is the fourth leading cause of cancer-related death worldwide. Depending on the extent of disease and competing comorbidities for mortality, multiple liver-directed therapy options exist for the treatment of hepatocellular carcinoma. Advancements in radiation oncology have led to the emergence of stereotactic body radiation therapy as a promising liver-directed therapy, which delivers high doses of radiation with a steep dose gradient to maximize local tumor control and minimize radiation-induced treatment toxicity. In this study, we review the current clinical data as well as the unresolved issues and controversies regarding stereotactic body radiation therapy for hepatocellular carcinoma: (1) Is there a radiation dose–response relationship with hepatocellular carcinoma? (2) What are the optimal dosimetric predictors of radiation-induced liver disease, and do they differ for patients with varying liver function? (3) How do we assess treatment response on imaging? (4) How does stereotactic body radiation therapy compare to other liver-directed therapy modalities, including proton beam therapy? Based on the current literature discussed, this review highlights future possible research and clinical directions.

Clinical significance of radiation-induced liver disease after stereotactic body radiation therapy for hepatocellular carcinoma

BACKGROUND/AIMS

The aim of this study was to investigate parameters that predict radiation-induced liver disease (RILD) following stereotactic body radiotherapy (SBRT) in patients with hepatocellular carcinoma (HCC) and to identify the clinical significance of RILD.

METHODS

We retrospectively reviewed the medical records of 117 HCC patients who were treated by SBRT from March 2011 to February 2015. RILD was defined as elevated liver transaminases more than five times the upper normal limit or a worsening of Child-Pugh (CP) score by 2 within 3 months after SBRT. All patients were assessed at 1 month and every 3 months after SBRT.

RESULTS

Median follow-up was 22.5 months (range, 3 to 56) after SBRT. RILD was developed in 29 of the 117 patients (24.7%). On univariate analysis, significant predictive factors of RILD were pretreatment CP score (p < 0.001) and normal liver volume (p = 0.002). Multivariate analysis showed that CP score was a significant predictor of RILD (p < 0.001). The incidence of RILD increased above a CP score of 6 remarkably. The rate of recovery from RILD decreased significantly above a CP score of 8. Survival analysis showed that CP score was an independent prognostic factor of overall survival (p = 0.001).

CONCLUSION

CP score is a significant factor to predict RILD in patients with chronic liver disease. RILD can be tolerated by patients with a CP score ≤ 7. However, careful monitoring of liver function is needed for patients with a CP score 7 after SBRT.

Protocol for the STRONG trial: stereotactic body radiation therapy following chemotherapy for unresectable perihilar cholangiocarcinoma, a phase I feasibility study

INTRODUCTION

For patients with perihilar cholangiocarcinoma (CCA), surgery is the only treatment modality that can result in cure. Unfortunately, in the majority of these patients, the tumours are found to be unresectable at presentation due to either local invasive tumour growth or the presence of distant metastases. For patients with unresectable CCA, palliative chemotherapy is the standard treatment yielding an estimated median overall survival (OS) of 12-15.2 months. There is no evidence from randomised trials to support the use of stereotactic body radiation therapy (SBRT) for CCA. However, small and most often retrospective studies combining chemotherapy with SBRT have shown promising results with OS reaching up to 33-35 months.

METHODS AND ANALYSIS

This study has been designed as a single-centre phase I feasibility trial and will investigate the addition of SBRT after standard chemotherapy in patients with unresectable perihilar CCA (T1-4 N0-1 M0). A total of six patients will be included. SBRT will be delivered in 15 fractions of 3-4.5 Gy (risk adapted). The primary objective of this study is to determine feasibility and toxicity. Secondary outcomes include local tumour control, progression-free survival (PFS), OS and quality of life. Length of follow-up will be 2 years. As an ancillary study, the personalised effects of radiotherapy will be measured in vitro, in patient-derived tumour and bile duct organoid cultures.

ETHICS AND DISSEMINATION

Ethics approval for the STRONG trial has been granted by the Medical Ethics Committee of Erasmus MC Rotterdam, the Netherlands. It is estimated that all patients will be included between October 2017 and October 2018. The results of this study will be published in a peer-reviewed journal, and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03307538; Pre-results.

Stereotactic body radiation therapy in primary hepatocellular carcinoma: current status and future directions

Stereotactic body radiation therapy (SBRT) is a form of radiation therapy that has been used in the treatment of primary hepatocellular carcinoma (HCC) over the past decade. To evaluate the clinical efficacy of SBRT in primary HCC, a literature search was conducted to identify original research articles published from January 2000 through January 2018 in PubMed on SBRT in HCC. All relevant studies published from 2004 to 2018 were included. Prospective studies demonstrated 2-year local control (LC) rates ranging from 64-95% and overall survival (OS) rates ranging from 34% (2-year) to 65% (3-year). Retrospective studies demonstrated 2-year LC rates of 44-90% and 2-year OS rates of 24-67%. Reported toxicities in primary HCC patients vary but SBRT appears to be relatively well tolerated. Studies comparing SBRT to radiofrequency ablation (RFA) are few, but they suggest SBRT may be more effective than RFA in specific primary HCC populations. Additionally, SBRT appears to increase the efficacy of both transarterial chemoembolization (TACE) and sorafenib in selected primary HCC populations.

How small is TOO small? New liver constraint is needed- Proton therapy of hepatocellular carcinoma patients with small normal liver

PURPOSE

This study evaluated the outcomes of hepatocellular carcinoma (HCC) patients with small normal liver volume (NLV) treated with proton beam therapy (PBT) and introduced estimated standard liver volume (eSLV) as a new constraint.

MATERIALS AND METHODS

HCC patients with NLV < 800 cm3 and no distant metastasis who received treatment in our proton center were included. The doses of PBT were mainly 72.6 Gray equivalents (GyE) in 22 fractions and 66 GyE in 10 fractions according to tumor locations. The Urata equation was used to calculate eSLV.

RESULTS

Twenty-two patients were treated between November 2015 and December 2016. The 1-year progression-free and overall survival rates were 40.4% and 81.8%, respectively. The 1-year in-field failure-free rate was 95.5%. NLV ranged from 483.9 to 795.8 cm3 (median = 673.8 cm3), eSLV ranged from 889.3 to 1290.0 cm3 (median = 1104.5 cm3), and the resulting NLV/eSLV ratio ranged from 44.3 to 81.2% (median = 57.7%). Non-irradiated liver volume (NILV) ranged from 232.9 to 531.6 cm3 (median = 391.2 cm3). The NILV/eSLV ratio ranged from 21.2 to 48.0% (median = 33.3%). NLV in the patients who received <30 GyE (rV30) ranged from 319.1 to 633.3 cm3 (median = 488.2 cm3), and their rV30/eSLV ratio ranged from 30.7 to 58.0%. None of our patients developed liver failure. One patient with initial abnormal liver enzyme levels developed non-classic radiation-induced liver disease (RILD).

CONCLUSION

From the viewpoint of minimal liver toxicity occurring in our patients with NLV < 800 cm3, conventional liver constraints involving the use of absolute volume could not accurately predict the risk of RILD. It is reasonable to start using individualized constraints with eSLV for HCC patients undergoing PBT. According to the study results, an NILV/eSLV ratio of >20% and an rV30/eSLV ratio of >30% are acceptable.

[Technical aspects and indications of extracranial stereotactic radiotherapy]

Extracranial stereotactic radiotherapy has developed considerably in recent years and is now an important part of the therapeutic alternatives to be offered to patients with cancer. It offers opportunities that have progressively led physicians to reconsider the therapeutic strategy, for example in the case of local recurrence in irradiated territory or oligometastatic disease. The literature on the subject is rich but, yet, there is no real consensus on therapeutic indications. This is largely due to the lack of prospective, randomized studies that have evaluated this technique with sufficient recoil. We propose a review of the literature on the technical aspects and indications of extracranial stereotactic radiotherapy.

Angiosomal radiopathologic analysis of transarterial radioembolization for the treatment of hepatocellular carcinoma

PURPOSE

To assess the radiopathologic correlation following Yttrium-90 transarterial radioembolization (TARE) of hepatocellular carcinoma (HCC) using variable radiodosimetry to identify imaging surrogates of histologic response.

METHODS

Twelve patients with HCC underwent ablative (≥ 190 Gy) and/or non-ablative (< 190 Gy) TARE delivered in a segmental, lobar, or combined fashion as a surgical neoadjuvant or bridge to transplantation. Both targeted tumor and treatment angiosome were analyzed before and after TARE utilizing hepatocyte-specific contrast-enhanced MRI or contrast-enhanced CT. Responses were graded using EASL and mRECIST criteria. Histologic findings including percent tumor necrosis and adjacent hepatic substrate effects were correlated with imaging features.

RESULTS

Complete pathologic necrosis (CPN) was observed in 7/12 tumors post-TARE. Ablative and non-ablative dosing resulted in CPN in 5/6 and 2/6 tumors, respectively. Hyperintensity on T2-weighted imaging, the absence of hepatocyte-specific gadolinium contrast uptake, and plateau or persistent enhancement kinetics in the angiosome correlated with CPN and performed similarly to EASL and mRECIST criteria in predicting CPN.

CONCLUSIONS

The absence of hepatocyte-specific contrast uptake, increased signal on T2-weighted sequences, and plateau or persistent enhancement in the angiosome may represent MRI surrogates of CPN following TARE of HCC. These findings correlated with EASL and mRECIST response criteria. Further investigation is needed to determine the role of these findings as possible adjuncts to conventional imaging criteria.

Hepatectomy versus stereotactic body radiotherapy for primary early hepatocellular carcinoma: A propensity-matched analysis in a single institution

OBJECTIVE

To evaluate the efficacy of both surgical resection and stereotactic body radiotherapy for small hepatocellular carcinoma.

BACKGROUND

Although the number of stereotactic body radiotherapies being performed for hepatocellular carcinoma has gradually increased, data comparing surgical resection and stereotactic body radiotherapy are limited.

METHODS

Between 2008 and 2015, a total of 281 patients with 1 to 3 small hepatocellular carcinoma tumors (≤3 cm in diameter), treated initially with curative intent (surgical resection, 254; stereotactic body radiotherapy, 27), were retrospectively analyzed. Overall survival and disease-free survival were compared in a propensity score matching analysis.

RESULTS

Patients in the surgical resection group tended to be younger, had more tumors, and had better hepatic function than those in the stereotactic body radiotherapy group (P < .05). The percent recurrence of the same sub-segment in the stereotactic body radiotherapy group was significantly higher than that in the surgical resection group (P = .0034). Propensity score analysis revealed that 54 patients with surgical resection and 27 with stereotactic body radiotherapy had the same baseline characteristics. The 5-year overall survival and disease-free survival rates for the surgical resection and stereotactic body radiotherapy groups were 75.2% vs 47.8% (P = .0149) and 33.8% vs 16.4% (P = .0512), respectively. Multivariate analysis showed that surgical resection was a significant favorable factor for overall survival and disease-free survival of patients with one to three small hepatocellular carcinomas.

CONCLUSION

Surgical resection provided better long-term overall survival and disease-free survival in patients with small hepatocellular carcinoma tumors. However, stereotactic body radiotherapy may be an effective alternative treatment for inoperable patients with early hepatocellular carcinoma.

A prospective study of the safety and efficacy of liver stereotactic body radiotherapy in patients with and without prior liver-directed therapy

BACKGROUND AND PURPOSE

To evaluate the safety and efficacy of liver stereotactic body radiotherapy (SBRT), and examine potential factors impacting outcomes including prior liver-directed therapy.

MATERIALS AND METHODS

Patients with ECOG 0-1, Child-Pugh Class A or B, and primary hepatocellular carcinoma (HCC) or liver metastases unsuitable for surgical resection or ablation were eligible for a prospective single arm trial. SBRT was delivered with a CyberKnife system to 45 Gy in 3 fractions with a predetermined dose de-escalation scheme. Adverse events, local control, and survival were assessed.

RESULTS

A total of 30 patients were enrolled. Eleven patients (37%) had HCC and 19 (63%) patients had liver metastases. Fourteen patients (47%) had prior liver-directed therapies including nine with liver resection, seven with trans-arterial chemoembolization, and six with radiofrequency ablation. Cumulative grade 2 and 3 acute toxicity occurred in 47% and 7% of patients, respectively. Similar rates of ≥grade 2 acute toxicity were observed between patients who had prior liver-directed treatments and those who did not. At a median follow-up of 12.7 months, 1-year local control and overall survival were 81% and 62%, respectively. Prior liver-directed therapy did not affect local control or survival.

CONCLUSIONS

Liver SBRT is a safe and effective treatment even in the setting of prior liver-directed surgical and ablative therapies.

Predictive Factors for Child-Pugh Score Elevation in Hepatocellular Carcinoma Patients Treated with Conformal Radiation Therapy: Dose-Volume Histogram Analysis

Aims and background

We designed the study to identify the clinical and dose-volumetric parameters associated with the risk of Child-Pugh score elevation in hepatocellular carcinoma patients treated with conformal radiation therapy.

Methods and study design

All 161 hepatocellular carcinoma patients in the study underwent 4D-computed tomography simulation, and a dose-volume histogram was generated after radiotherapy planning. Patients who had an elevated Child-Pugh (e-CP) score of 2 or more without progressive disease within 3 months were defined as e-CP positive.

Results

Twenty-six of 142 patients without progressive disease were e-CP positive. Pretreatment Child-Pugh class, further treatment within 30 days of radiotherapy, lymph node metastasis, mean liver dose, V20 Gy, V25 Gy, and V30 Gy were significantly correlated with e-CP positivity. The e-CP developed in 13 of 106 patients (12.3%) with V30 Gy of ≤28.1% and in 13 of 36 patients (36.1%) with V30 Gy >28.1% ( P = 0.001).

Conclusions

Our data demonstrate that mean liver dose, V10 Gy, V20 Gy, V25 Gy, and V30 Gy are independent dose-volumetric predictors for e-CP positivity in hepatocellular carcinoma patients treated with conformal radiation therapy. V30 Gy should be limited to less than 28.1% to minimize the risk of e-CP.

Radiation Dose-Volume Effects for Liver SBRT

Stereotactic body radiation therapy (SBRT) has emerged as an effective, noninvasive treatment option for primary liver cancer and metastatic disease occurring in the liver. Although SBRT can be highly effective for establishing local control in hepatic malignancies, a tradeoff exists between tumor control and normal tissue complications. The objective of the present study was to review the normal tissue dose-volume effects for SBRT-induced liver and gastrointestinal toxicities and derive normal tissue complication probability models.

Defining Radiation-Induced Hepatic Toxicity in Hepatocellular Carcinoma Patients Treated with Stereotactic Body Radiotherapy

The definition and criteria of radiation-induced hepatic toxicity (RIHT) in hepatocellular carcinoma patients vary among studies. Therefore, the reported rates of RIHT differ among studies, and this causes confusion. In this study, we evaluated RIHT using several laboratory and clinical parameters, and analyzed which criterion is more correlated with RT and survival. Forty-five HCC patients treated with stereotactic body radiotherapy were included for the analysis. All patients had unresectable HCC and Child-Pugh (CP) class A or B baseline liver function. A median total dose of 45 Gy was delivered by CyberKnife in 3 fractions. For individual laboratory parameter, ≥ grade 2 toxicity development of bilirubin, albumin, or prothrombin time by Common Terminology Criteria of Adverse Effects (CTCAE) was correlated with mean liver dose and survival. However, serum transaminases had no correlation with liver mean dose and survival, and were rather affected by other local treatments. Compared to the CTCAE, the increase in the CP score of 2 points or more was better correlated with liver failure and overall survival, and it was not affected by other local treatments or tumor progression. We concluded RIHT was better defined by the change in the CP score rather than the CTCAE in patients treated by stereotactic body radiotherapy for HCC.

Analysis of the factors affecting the safety of robotic stereotactic body radiation therapy for hepatocellular carcinoma patients

Objective

The objective of this study was to investigate the safety of robotic stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) patients and its related factors.

Methods

A total of 74 HCC patients with Child-Turcotte-Pugh (CTP) Class A were included in a multi-institutional, single-arm Phase II trial (NCT 02363218) between February 2013 and August 2016. All patients received SBRT treatment at a dose of 45 Gy/3f. The liver function was compared before and after SBRT treatment by the analysis of adverse hepatic reactions and changes in CTP classification.

Results

After SBRT treatment, eight patients presented with decreases in CTP classification and 13 patients presented with ≥ grade 2 hepatic adverse reactions. For patients presenting with ≥ grade 2 hepatic adverse reactions, the total liver volume of ≤1,162 mL and a normal liver volume (total liver volume - gross tumor volume [GTV]) of ≤1,148 mL were found to be independent risk factors and statistically significant (P<0.05).

Conclusion

The total liver volume and normal liver volume are associated with the occurrence of ≥ grade 2 hepatic adverse reactions after SBRT treatment on HCC patients. Therefore, if the fractionated scheme of 45 Gy/3f is applied in SBRT for HCC patients, a total liver volume >1,162 mL and a normal liver volume >1,148 mL should be ensured to improve therapeutic safety.

Toward consensus reporting of radiation-induced liver toxicity in the treatment of primary liver malignancies: Defining clinically relevant endpoints

BACKGROUND

Our purpose was to define the most clinically relevant "nonclassic" radiation-induced liver disease (RILD) endpoints in cirrhotic patients receiving stereotactic body radiation therapy or proton beam therapy for primary liver cancer.

METHODS AND MATERIALS

We retrospectively collected pretreatment, detailed toxicity (≤6 months posttreatment), and outcomes data from 48 patients. Deaths were examined for association with RILD. Univariate and multivariate Cox models defined significant predictors of overall survival (OS)/RILD-specific survival (RILD-SS).

RESULTS

With median follow-up of 13 months, 23 patients (48%) had an increase in Child-Pugh (CP) score (≥2, 25%) and 3 (6%) had ≥G3 transaminase elevation. Of 18 deaths, 6 were potentially ascribed to RILD. Univariate analysis showed that CP score increases of ≥1 and ≥2 and CP class change predicted OS, as did ≥G3 aspartate transaminase (AST) elevation and ≥1 Common Terminology Criteria for Adverse Events (CTCAE) AST toxicity grade change. On multivariate analysis, CP score increase of ≥2 and ≥1 CTCAE AST toxicity grade change were the strongest independent nonclassic RILD predictors of OS. For RILD-SS, CP score increases of ≥2, ≥grade 3 CTCAE alanine transaminase, and ≥grade 2 bilirubin elevations were predictive.

CONCLUSIONS

Increased CP score ≥2 strongly predicts for both OS and RILD-SS and should be reported in future studies along with transaminase elevations, which are also predictive of outcomes.

A block matching based approach with multiple simultaneous templates for the real-time 2D ultrasound tracking of liver vessels

PURPOSE

The implementation of motion management techniques in radiation therapy can aid in mitigating uncertainties and reducing margins. For motion management to be effective, it is necessary to track key structures both accurately and at a real-time speed. Therefore, the focus of this work was to develop a 2D algorithm for the real-time tracking of ultrasound features to aid in radiation therapy motion management.

MATERIALS AND METHODS

The developed algorithm utilized a similarity measure-based block matching algorithm incorporating training methods and multiple simultaneous templates. The algorithm is broken down into three primary components, all of which use normalized cross-correlation (NCC) as a similarity metric. First, a global feature shift to account for gross displacements from the previous frame is determined using large block sizes which encompass the entirety of the feature. Second, the most similar reference frame is chosen from a series of training images that are accumulated during the first K frames of tracking to aid in contour consistency and provide a starting point for the localized template initialization. Finally, localized block matching is performed through the simultaneous use of both a training frame and the previous frame. The localized block matching utilizes a series of templates positioned at the boundary points of the training and previous contours. The weighted final boundary points from both the previous and the training frame are ultimately combined and used to determine an affine transformation from the previous frame to the current frame.

RESULTS

A mean tracking error of 0.72 ± 1.25 mm was observed for 85 point-landmarks across 39 ultrasound sequences relative to manual ground truth annotations. The image processing speed per landmark with the GPU implementation was between 41 and 165 frames per second (fps) during the training set accumulation, and between 73 and 234 fps after training set accumulation. Relative to a comparable multithreaded CPU approach using OpenMP, the GPU implementation resulted in speedups between -30% and 355% during training set accumulation, and between -37% and 639% postaccumulation.

CONCLUSIONS

Initial implementations indicated an accuracy that was comparable to or exceeding those achieved by alternative 2D tracking methods, with a computational speed that is more than sufficient for real-time applications in a radiation therapy environment. While the overall performance reached levels suitable for implementation in radiation therapy, the observed increase in failures for smaller features, as well as the algorithm's inability to be applied to nonconvex features warrants additional investigation to address the shortcomings observed.

Pre-radiotherapy neutrophil-to-lymphocyte ratio as an independent prognostic factor in patients with locally advanced hepatocellular carcinoma treated with radiotherapy

We aimed to investigate the pre-radiotherapy neutrophil-to-lymphocyte ratio (prNLR) as a prognostic factor in patients with locally advanced hepatocellular carcinoma (HCC) treated with radiotherapy (RT), and to determine the optimal cut-off value for prNLR. We retrospectively evaluated 56 patients with locally advanced HCC treated with RT (helical tomotherapy) between March 2006 and February 2012. The optimal cut-off value was determined by using a maximally selected log-rank test. Prognostic factors that influence the local progression-free survival (PFS) and overall survival (OS) were evaluated. A prNLR of 2.1 was determined to be the optimal cut-off value. In a comparison between the high-prNLR group and the low-prNLR group, there was a 13.1-month difference in the median OS (10.3 vs. 23.4 months, p = 0.003) and a 10.4-month difference in the median local PFS (7.1 vs. 17.5 months, p = 0.001). On multivariate analysis of prognostic factors for local PFS and OS, the prNLR was identified as an independent prognostic factor, and the hazard ratio was 4.2 and 2.5, respectively. We demonstrated that a low prNLR was significantly associated with better PFS and OS in patients with locally advanced HCC treated with RT, and the prNLR should be considered as an independent prognostic factor in these patients.

放射性肝损伤的研究进展

我国是肝癌大国, 肝癌的年发病及死亡人数均占全球一半以上. 很多患者在肝癌发展的不同时期会接受放射治疗. 放射性肝损伤(radiation-induced liver damage, RILD)是由放射治疗导致的一种临床亚急性、慢性肝脏损伤, 是胸部和上腹部肿瘤放疗及骨髓移植前预处理中最严重的并发症之一. RILD极大地影响了胸腹部肿瘤, 特别是肝癌的放疗疗效. 因此, 本综述对RILD的病理、影像学特点、临床评估及防治作一归纳总结.