Radiation-induced liver disease in three-dimensional conformal radiation therapy for primary liver carcinoma: the risk factors and hepatic radiation tolerance

Local and Global Function Model of the Liver

PURPOSE

To develop a local and global function model in the liver based on regional and organ function measurements to support individualized adaptive radiation therapy (RT).

METHODS AND MATERIALS

A local and global model for liver function was developed to include both functional volume and the effect of functional variation of subunits. Adopting the assumption of parallel architecture in the liver, the global function was composed of a sum of local function probabilities of subunits, varying between 0 and 1. The model was fit to 59 datasets of liver regional and organ function measures from 23 patients obtained before, during, and 1 month after RT. The local function probabilities of subunits were modeled by a sigmoid function in relating to MRI-derived portal venous perfusion values. The global function was fitted to a logarithm of an indocyanine green retention rate at 15 minutes (an overall liver function measure). Cross-validation was performed by leave-m-out tests. The model was further evaluated by fitting to the data divided according to whether the patients had hepatocellular carcinoma (HCC) or not.

RESULTS

The liver function model showed that (1) a perfusion value of 68.6 mL/(100 g · min) yielded a local function probability of 0.5; (2) the probability reached 0.9 at a perfusion value of 98 mL/(100 g · min); and (3) at a probability of 0.03 [corresponding perfusion of 38 mL/(100 g · min)] or lower, the contribution to global function was lost. Cross-validations showed that the model parameters were stable. The model fitted to the data from the patients with HCC indicated that the same amount of portal venous perfusion was translated into less local function probability than in the patients with non-HCC tumors.

CONCLUSIONS

The developed liver function model could provide a means to better assess individual and regional dose-responses of hepatic functions, and provide guidance for individualized treatment planning of RT.

Dosimetric comparison of carbon ion radiotherapy and stereotactic body radiotherapy with photon beams for the treatment of hepatocellular carcinoma

Background

The purpose of this study was to compare carbon ion radiotherapy (C-ion RT) and stereotactic radiotherapy (SBRT) with photon beams for the treatment of hepatocellular carcinoma (HCC), specifically with regard to the dose volume parameters for target coverage and normal tissue sparing.

Methods

Data of 10 patients who were treated using C-ion RT with a total dose of 60 Gy(RBE) in four fractions were used. The virtual plan of SBRT was simulated on the treatment planning computed tomography images of C-ion RT. Dose volume parameters such as minimum dose covering 90 % of the planning target volume (PTV D90), homogeneity index (HI), conformity index (CI), mean liver dose (MLD), volume of the liver receiving 5 to 60 Gy (V5-60), and max point dose (Dmax) of gastrointestinal (GI) tract were calculated from both treatment plans.

Results

The PTV D90 was 59.6 ± 0.2 Gy(RBE) in C-ion RT, as compared to 56.6 ± 0.3 Gy in SBRT (p < 0.05). HI and CI were 1.19 ± 0.03 and 0.79 ± 0.06, respectively in C-ion RT, as compared to 1.21 ± 0.01 and 0.37 ± 0.02, respectively in SBRT. Only CI showed a significant difference between two modalities. Mean liver dose was 8.1 ± 1.4 Gy(RBE) in C-ion RT, as compared to 16.1 ± 2.5 Gy in SBRT (p < 0.05). V5 to V50 of liver were higher in SBRT than C-ion RT and significant differences were observed for V5, V10 and V20. Dmax of the GI tract was higher in SBRT than C-ion RT, but did not show a significantly difference.

Conclusions

C-ion RT provides an advantage in both target conformity and normal liver sparing compared with SBRT.

Radiation-Induced Liver Injury in Three-Dimensional Conformal Radiation Therapy (3D-CRT) for Postoperative or Locoregional Recurrent Gastric Cancer: Risk Factors and Dose Limitations

PURPOSE

This study examined the status of radiation-induced liver injury in adjuvant or palliative gastric cancer radiation therapy (RT), identified risk factors of radiation-induced liver injury in gastric cancer RT, analysed the dose-volume effects of liver injury, and developed a liver dose limitation reference for gastric cancer RT.

METHODS AND MATERIALS

Data for 56 post-operative gastric cancer patients and 6 locoregional recurrent gastric cancer patients treated with three-dimensional conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT) from Sep 2007 to Sep 2009 were analysed. Forty patients (65%) were administered concurrent chemotherapy. Pre- and post-radiation chemotherapy were given to 61 patients and 43 patients, respectively. The radiation dose was 45-50.4 Gy in 25-28 fractions. Clinical parameters, including gender, age, hepatic B virus status, concurrent chemotherapy, and the total number of chemotherapy cycles, were included in the analysis. Univariate analyses with a non-parametric rank test (Mann-Whitney test) and logistic regression test and a multivariate analysis using a logistic regression test were completed. We also analysed the correlation between RT and the changes in serum chemistry parameters [including total bilirubin, (TB), direct bilirubin (D-TB), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and serum albumin (ALB)] after RT.

RESULTS

The Child-Pugh grade progressed from grade A to grade B after radiotherapy in 10 patients. A total of 16 cases of classic radiation-induced liver disease (RILD) were observed, and 2 patients had both Child-Pugh grade progression and classic RILD. No cases of non-classic radiation liver injury occurred in the study population. Among the tested clinical parameters, the total number of chemotherapy cycles correlated with liver function injury. V35 and ALP levels were significant predictive factors for radiation liver injury.

CONCLUSIONS

In 3D-CRT for gastric cancer patients, radiation-induced liver injury may occur and affect the overall treatment plan. The total number of chemotherapy cycles correlated with liver function injury, and V35 and ALP are significant predictive factors for radiation-induced liver injury. Our dose limitation reference for liver protection is feasible.

Radiation induced liver disease: A clinical update

Radiation-induced liver disease (RILD) or radiation hepatitis is a sub-acute form of liver injury due to radiation. It is one of the most dreaded complications of radiation which prevents radiation dose escalation and re-irradiation for hepatobiliary or upper gastrointestinal malignancies. This complication should be kept in mind whenever a patient is planned for irradiation of these malignancies. Although, incidence of RILD is decreasing due to better knowledge of liver tolerance, improved investigation modalities and modern radiation delivery techniques, treatment options are still limited. In this review article, we have focussed on patho-physiology, risk factors, prevention and management of RILD.

Clinical utility of gadoxetate disodium-enhanced hepatic MRI for stereotactic body radiotherapy of hepatocellular carcinoma

PURPOSE

To investigate the utility of gadoxetate disodium-enhanced hepatic MRI (EOB-MRI) for stereotactic body radiotherapy (SBRT) to treat hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

We divided 30 HCC patients who underwent SBRT into group A (no change in their Child-Pugh score 6 months post-SBRT) and group B (increased score 6 months post-SBRT). EOB-MRI was performed before and 6 months after SBRT. We calculated the liver-spleen contrast (LSC) ratio for each radiation dose area on hepatobiliary phase scans (LSCbefore using images obtained before SBRT and LSCafter using images acquired after SBRT) and the weighted LSC (W-LSC) as: [(mean LSCbefore (0-30 Gy) × liver volume (0-30 Gy) + mean LSCbefore (30 Gy-) × liver volume (30 Gy-))/total liver volume]. Then we compared the W-LSC, percentage of the liver volume exposed to >20 Gy (V20), and mean liver dose in the two groups.

RESULTS

The LSCafter at 48, 40, and 30 Gy to the liver was statistically lower than the unirradiated area of the liver (p < 0.01). Univariate analysis showed that only W-LSC was significantly associated with group B (p = 0.02).

CONCLUSION

W-LSC was a useful parameter for predicting changes in hepatic function after SBRT.

Mesenchymal stem cell-conditioned medium prevents radiation-induced liver injury by inhibiting inflammation and protecting sinusoidal endothelial cells

Current management of radiation-induced liver injury is limited. Sinusoidal endothelial cell (SEC) apoptosis and inflammation are considered to be initiating events in hepatic damage. We hypothesized that mesenchymal stem cells (MSCs) possess anti-apoptotic and anti-inflammatory actions during hepatic irradiation, acting via paracrine mechanisms. This study aims to examine whether MSC-derived bioactive components are protective against radiation-induced liver injury in rats. MSC-conditioned medium (MSC-CM) was generated from rat bone marrow-derived MSCs. The effect of MSC-CM on the viability of irradiated SECs was examined by flow cytometric analysis. Activation of the Akt and ERK pathways was analyzed by western blot. MSC-CM was also delivered to Sprague-Dawley rats immediately before receiving liver irradiation, followed by testing for pathological features, changes in serum hyaluronic acid, ALT, and inflammatory cytokine levels, and liver cell apoptosis. MSC-CM enhanced the viability of irradiated SECs in vitro and induced Akt and ERK phosphorylation in these cells. Infusion of MSC-CM immediately before liver irradiation provided a significant anti-apoptotic effect on SECs and improved the histopathological features of injury in the irradiated liver. MSC-CM also reduced the secretion and expression of inflammatory cytokines and increased the expression of anti-inflammatory cytokines. MSC-derived bioactive components could be a novel therapeutic approach for treating radiation-induced liver injury.

Multidisciplinary perspective of hepatocellular carcinoma: A Pacific Northwest experience

Hepatocellular carcinoma (HCC) is the most rapidly increasing type of cancer in the United States. HCC is a highly malignant cancer, accounting for at least 14000 deaths in the United States annually, and it ranks third as a cause of cancer mortality in men. One major difficulty is that most patients with HCC are diagnosed when the disease is already at an advanced stage, and the cancer cannot be surgically removed. Furthermore, because almost all patients have cirrhosis, neither chemotherapy nor major resections are well tolerated. Clearly there is need of a multidisciplinary approach for the management of HCC. For example, there is a need for better understanding of the fundamental etiologic mechanisms that are involved in hepatocarcinogenesis, which could lead to the development of successful preventive and therapeutic modalities. It is also essential to define the cellular and molecular bases for malignant transformation of hepatocytes. Such knowledge would: (1) greatly facilitate the identification of patients at risk; (2) prompt efforts to decrease risk factors; and (3) improve surveillance and early diagnosis through diagnostic imaging modalities. Possible benefits extend also to the clinical management of this disease. Because there are many factors involved in pathogenesis of HCC, this paper reviews a multidisciplinary perspective of recent advances in basic and clinical understanding of HCC that include: molecular hepatocarcinogenesis, non-invasive diagnostics modalities, diagnostic pathology, surgical modality, transplantation, local therapy and oncological/target therapeutics.

Feasibility and efficacy of helical tomotherapy in cirrhotic patients with unresectable hepatocellular carcinoma

Background

This study is to evaluate the toxicity and outcomes of helical tomotherapy (HT) in patients treated for unresectable hepatocellular carcinoma (HCC).

Methods

From March 2008 to September 2010, 38 patients with unresectable HCC were treated with HT. The median patient age was 67 years (range, 45–85). The median follow-up period was 17.2 months (range, 7–46). All patients had liver cirrhosis. Median radiation dose was 54 Gy (range, 46–71.8) delivered in 1.8 to 2.4-Gy fractions. The planning target volumes were 241.2 ± 153.1 cm³ (range, 45.8–722.4). Treatment responses were assessed in 3–6 months after HT.

Results

There was a complete response in 2 patients (5.2 %), partial response in 18 patients (47.4 %), stable disease in 13 patients (34.2 %), and progressive disease in 5 patients (13.2 %). The median overall survival was 12.6 months, and 1- and 2-year overall survival rates were 56.2 and 31.7 %, respectively. Eastern Cooperative Oncology Group (ECOG score, p = 0.008), Child-Pugh classification (p = 0.012), albumin (p = 0.046), and hemoglobin (p = 0.028) were significant parameters that predicted primary tumor response to radiotherapy in multivariate analysis. ECOG score (p = 0.012), Child-Pugh class (p = 0.026), and response to radiotherapy (p = 0.016) were independent prognostic factors for overall survival in multivariate analysis. Responders had better overall survival than non-responders (23.6 vs. 5.8 months, p < 0.001). The 1- and 2-year overall survival rates for responders were 68.3 and 57 %, respectively, while for non-responders, they were 0 %. The 1- and 2-year local control rates were 88.2 and 82.3 %, respectively. Five patients (13.2 %) had grade 3 or greater liver toxicity, and one patient (2.6 %) had a grade 3 gastric ulcer. No treatment-related liver failure or death was documented in this study.

Conclusions

Radiotherapy using HT seems to be a safe and effective treatment option for unresectable HCC patients. This study indicates that HT is a feasible treatment even in patients without good performance status and hepatic function reservation.

Influence of liver toxicities on prognosis after stereotactic body radiation therapy for hepatocellular carcinoma

AIM

To better define clinically relevant non-classic radiation-induced liver disease (RILD) following stereotactic body radiotherapy (SBRT) in patients with small hepatocellular carcinoma (HCC).

METHODS

We retrospectively evaluated the influence of acute liver toxicities on fatal hepatic failure in HCC patients treated with SBRT. Between April 2006 and February 2012, 194 HCC were treated with SBRT. Among them, patients followed up for more than 6 months were eligible. Laboratory results and Child-Pugh (CP) scores were obtained before treatment and at monthly follow-up visits. Toxicities were evaluated by the Common Terminology Criteria for Adverse Events version 4.0. Possible definitions of RILD were evaluated with respect to fatal hepatic failure within 12 months.

RESULTS

One hundred and eighty HCC were evaluated with a median follow-up of 28.2 months. Fatal hepatic failure within 12 months occurred in eight patients (4%). On univariate analysis, grade 3 or more elevated transaminases, CP score of 8 or more, and/or grade 3 or more decreased platelet count significantly predicted fatal hepatic failure within 12 months. Combinations of these factors (i.e. having at least one criterion) also predicted fatal hepatic failure within 12 months (16% with criteria vs 1% without criteria). Two-year overall survival rates for patients with and without RILD was 64.9% and 83.8% (P < 0.001), respectively.

CONCLUSION

We identified three criteria that affected overall survival in HCC patients treated with SBRT. Further prospective studies are warranted to validate the safety and effect of SBRT for HCC.

Differential hepatic avoidance radiation therapy: Proof of concept in hepatocellular carcinoma patients

PURPOSE

To evaluate the feasibility of a novel planning concept that differentially redistributes RT dose away from functional liver regions as defined by (99m)Tc-sulphur colloid (SC) uptake on patient SPECT/CT images.

MATERIALS AND METHODS

Ten HCC patients with different Child-Turcotte-Pugh scores (A5-B9) underwent SC SPECT/CT scans in treatment position prior to RT that were registered to planning CT scans. Proton pencil beam scanning (PBS) therapy plans were optimized to deliver 37.5-60.0Gy (RBE) over 5-15 fractions using single field uniform dose technique robust to range and setup uncertainty. Photon volumetrically modulated arc therapy (VMAT) plans were optimized to the same prescribed dose and minimum target coverage. For both treatment modalities, differential hepatic avoidance RT (DHART) plans were generated to decrease dose to functional liver volumes (FLV) defined by a range of thresholds relative to maximum SC uptake (43-90%) in the tumor-subtracted liver. Radiation dose was redistributed away from regions of increased SC uptake in each FLV by linearly scaling mean dose objectives during PBS or VMAT optimization. DHART planning feasibility was assessed by a significantly negative Spearman's rank correlation (RS) between dose difference and SC uptake. Patient, tumor, and treatment planning characteristics were tested for association to DHART planning feasibility using non-parametric Kruskal-Wallis ANOVA.

RESULTS

Compared to conventional plans, DHART plans achieved a 3% FLV dose reduction for every 10% SC uptake increase. DHART planning was feasible in the majority of patients with 60% of patients having RS<-0.5 (p<0.01, range -1.0 to 0.2) and was particularly effective in 30% of patients (RS<-0.9). Mean dose to FLV was reduced by up to 20% in these patients. Only fractionation regimen was associated with DHART planning feasibility: 15 fraction courses were more feasible than 5-6 fraction courses (RS<-0.93 vs. RS>-0.60, p<0.02).

CONCLUSION

Differential avoidance of functional liver regions defined on sulphur colloid SPECT/CT is achievable with either photon VMAT or proton PBS therapy. Further investigation with phantom studies and in a larger cohort of patients may validate the utility of DHART planning for HCC radiotherapy.

Liver regeneration and energetic changes in rats following hepatic radiation therapy and hepatocyte transplantation by ³¹P MRSI

BACKGROUND & AIMS

Radiation-induced liver damage (RILD) is a poorly understood and potentially devastating complication of hepatic radiation therapy (RT) for liver cancers. Previous work has demonstrated that hepatocyte transplantation (HT) can ameliorate RILD in rats. We hypothesized that RT inhibits generation of cellular ATP and suppresses hepatic regeneration.

METHODS

To study the metabolic changes that occur in RILD with and without HT, (31)P MRSI data were acquired in rats treated with partial hepatectomy (PH) alone, PH with hepatic irradiation (PHRT) or PHRT with HT (PHRT+HT).

RESULTS

Both [γ -ATP] and ATP/Pi (31)P MRSI signal ratio initially decreased and subsequently returned to baseline levels within 2 weeks after PH, which is consistent with other published data. Persistently reduced [γ-ATP] and ATP/Pi (31)P MRSI signal ratio were observed in rats up to 20 weeks after PHRT. However, progressive increases in [γ -ATP] were observed over time in the group of rats receiving PHRT+HT. Normal [γ -ATP] was observed 20 weeks after PHRT+HT (vs. PH alone), although, ATP/Pi levels did not return to normal after PHRT +HT. Ex vivo histological studies were performed to confirm liver repopulation with transplanted hepatocytes and the amelioration of pathologic changes of RILD.

CONCLUSIONS

These findings suggest that (31)P MRSI can be used to monitor the progress of RILD and its amelioration using transplanted hepatocytes to simultaneously restore metabolic function while replacing host hepatocytes damaged by RT.

Molecular responses of radiation-induced liver damage in rats

The aim of the present study was to investigate the molecular responses involved in radiation‑induced liver damage (RILD). Sprague‑Dawley rats (6‑weeks‑old) were irradiated once at a dose of 20 Gy to the right upper quadrant of the abdomen. The rats were then sacrificed 3 days and 1, 2, 4, 8 and 12 weeks after irradiation and rats, which were not exposed to irradiation were used as controls. Weight measurements and blood was obtained from the rats and liver tissues were collected for histological and apoptotic analysis. Immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis were performed to measure the expression levels of mRNAs and proteins, respectively. The serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were increased significantly in the RILD rats. Histological investigation revealed the proliferation of collagen and the formation of fibrotic tissue 12 weeks after irradiation. Apoptotic cells were observed predominantly 2 and 4 weeks after irradiation. The immunohistochemistry, RT‑qPCR and western blot analysis all revealed the same pattern of changes in the expression levels of the molecules assessed. The expression levels of transforming growth factor‑β1 (TGF‑β1), nuclear factor (NF)‑κB65, mothers against decapentaplegic homolog 3 (Smad3) and Smad7 and connective tissue growth factor were increased during the recovery period following irradiation up to 12 weeks. The expression levels of tumor necrosis factor‑α, Smad7 and Smad4 were only increased during the early phase (first 4 weeks) of recovery following irradiation. In the RILD rat model, the molecular responses indicated that the TGF‑β1/Smads and NF‑κB65 signaling pathways are involved in the mechanism of RILD recovery.

4DCT Simulation With Synchronized Contrast Injection in Liver SBRT Patients

BACKGROUND/PURPOSE

Delivering stereotactic body radiotherapy for liver metastases remains a challenge because of respiratory motion and poor visibility without intravenous contrast. The purpose of this article is to describe a novel and simple computed tomography (CT) simulation process of integrating timed intravenous contrast that could overcome the uncertainty of target delineation.

METHODS AND RESULTS

The simulation involves two 4-dimensional CT (4DCT) scans. The first scan only encompasses the immediate region of the tumor and surrounding tissue, which reduces the 4DCT scan time so that it can be optimally timed with intravenous contrast injection. The second 4DCT scan covers a larger volume and is used as the primary CT data set for dose calculation, as well as patient setup verification on the treatment unit. The combination of the two 4DCT scans allows us to optimally visualize liver metastases over all phases of the breathing cycle while simultaneously acquiring a long enough 4DCT data set that is suitable for planning and patient setup verification.

CONCLUSION

This simulation technique allows for a better target definition when treating liver metastases, without being invasive.

The role of radiotherapy in the treatment of hepatocellular carcinoma with portal vein tumor thrombus

The aim of this study was to evaluate the role of radiotherapy in the treatment of hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVT) and to determine the prognostic factors for overall survival. Altogether, 106 patients with HCC and PVT referred for radiotherapy between 2004 and 2009 were retrospectively reviewed. A total of 60 Gy in 30 daily fractions was delivered with intensity-modulated radiotherapy techniques. Patient-related and treatment-related factors were analyzed to evaluate their prognostic significance for the overall survival rate. Complete response was noted in 10 patients and partial response in 55 patients. The liver lesions had become resectable after the completion of radiotherapy in 12 patients, and surgery was subsequently performed. One or two courses of transarterial chemoembolization (TACE) were administered to 19 patients following radiotherapy. The 1-year and 2-year overall survival rates were 34.7% and 11%, respectively, and the median survival was 7 months for the entire cohort of patients. Post-radiotherapy treatment modality, response to radiotherapy and JIS score were demonstrated as independent prognostic factors for overall survival (P = 0.003, P < 0.001, P < 0.001, respectively). For patients who received surgical intervention after radiotherapy, the median survival was 30 months and the 2-year overall survival rate was 67%. Radiotherapy achieved a 61.5% objective response rate and prolonged survival in patients with PVT. The liver tumors had become resectable after radiotherapy in 11% of patients. Our results suggested that radiotherapy could offer survival benefits and should be considered as a treatment option for patients with PVT. Radiotherapy could also be considered as a preoperative treatment modality in patients with HCC and PVT.

Clinical decision tool for optimal delivery of liver stereotactic body radiation therapy: Photons versus protons

PURPOSE

Stereotactic body radiation therapy (SBRT) for treatment of liver tumors is often limited by liver dose constraints. Protons offer potential for more liver sparing, but clinical situations in which protons may be superior to photons are not well described. We developed and validated a treatment decision model to determine whether liver tumors of certain sizes and locations are more suited for photon versus proton SBRT.

METHODS AND MATERIALS

Six spherical mock tumors from 1 to 6 cm in diameter were contoured on computed tomography images of 1 patient at 4 locations: dome, caudal, left medial, and central. Photon and proton plans were generated to deliver 50 Gy in 5 fractions to each tumor and optimized to deliver equivalent target coverage and maximal liver sparing. Using these plans, we developed a hypothesis-generating model to predict the optimal modality for maximal liver sparing based on tumor size and location. We then validated this model in 10 patients with liver tumors.

RESULTS

Protons spared significantly more liver than photons for dome or central tumors ≥3 cm (dome: 134 ± 21 cm(3), P = .03; central: 108 ± 4 cm(3), P = .01). Our model correctly predicted the optimal SBRT modality for all 10 patients. For patients with dome or central tumors ≥3 cm, protons significantly increased the volume of liver spared (176 ± 21 cm(3), P = .01) and decreased the mean liver dose (8.4 vs 12.2 Gy, P = .01) while offering no significant advantage for tumors <3 cm at any location or for caudal and left medial tumors of any size.

CONCLUSIONS

When feasible, protons should be considered as the radiation modality of choice for dome and central tumors >3 cm to allow maximal liver sparing and potentially reduce radiation toxicity. Protons should also be considered for any tumor >5 cm if photon plans fail to achieve adequate coverage or exceed the mean liver threshold.

Efficacy of hepatic arterial infusion chemotherapy in combination with irradiation for advanced hepatocellular carcinoma with portal vein invasion

BACKGROUND

The presence of portal vein tumor thrombosis (PVTT) is a poor prognostic factor for patients with hepatocellular carcinomas (HCC). The purpose of this study was to determine the treatment effect of irradiation in combination with hepatic arterial infusion chemotherapy (HAIC) for these patients.

METHODS

We retrospectively examined the outcome of 67 HCC patients with PVTT of the main trunk or first branch who received HAIC alone or with concurrent irradiation for PVTT (CCRT).

RESULTS

Thirty-four patients received HAIC, and 33 patients received CCRT. The time to progression (TTP) of PVTT in the CCRT group was significantly longer than in the HAIC group (p < 0.01), and the TTP of intrahepatic nodules in the CCRT group tended to be longer than in the HAIC group (p = 0.06). The objective response rates of intrahepatic nodules (52 vs. 18%, p < 0.01) and PVTT (45 vs. 18%, p = 0.01) were both significantly higher in the CCRT group than in the HAIC group, respectively. No significant difference in overall survival was found between the two groups (p = 0.14); however, the median survival time in the CCRT group was longer than that in the HAIC group (12.4 vs. 5.7 months, respectively).

CONCLUSIONS

CCRT might be a promising treatment for advanced-stage HCC with PVTT. CCRT prolonged the TTP of intrahepatic nodules and PVTT, and it improved the objective response rate of intrahepatic nodules and PVTT.

Incorporating GSA-SPECT into CT-based dose-volume histograms for advanced hepatocellular carcinoma radiotherapy

In single photon emission computed tomography-based three-dimensional radiotherapy (SPECT-B-3DCRT), images of Tc-99m galactosyl human serum albumin (GSA), which bind to receptors on functional liver cells, are merged with the computed tomography simulation images. Functional liver is defined as the area of normal liver where GSA accumulation exceeds that of hepatocellular carcinoma (HCC). In cirrhotic patients with a gigantic, proton-beam-untreatable HCC of ≥ 14 cm in diameter, the use of SPECT-B-3DCRT in combination with transcatheter arterial chemoembolization achieved a 2-year local tumor control rate of 78.6% and a 2-year survival rate of 33.3%. SPECT-B-3DCRT was applied to HCC to preserve as much functional liver as possible. Sixty-four patients with HCC, including 30 with Child B liver cirrhosis, received SPECT-B-3DCRT and none experienced fatal radiation-induced liver disease (RILD). The Child-Pugh score deteriorated by 1 or 2 in > 20% of functional liver volume that was irradiated with ≥ 20 Gy. The deterioration in the Child-Pugh score decreased when the radiation plan was designed to irradiate ≤ 20% of the functional liver volume in patients given doses of ≥ 20 Gy (_FLV_20Gy). Therefore, _FLV_20Gy≤ 20% may represent a safety index to prevent RILD during 3DCRT for HCC. To supplement _FLV_20Gy as a qualitative index, we propose a quantitative indicator, F_20Gy, which was calculated as F_20Gy = 100% × (the GSA count in the area irradiated with ≥ 20 Gy)/(the GSA count in the whole liver).

Bone marrow-derived stromal cell therapy in cirrhosis: clinical evidence, cellular mechanisms, and implications for the treatment of hepatocellular carcinoma

Current treatment options for hepatocellular carcinoma (HCC) are often limited by the presence of underlying liver disease. In patients with liver cirrhosis, surgery, chemotherapy, and radiation therapy all carry a high risk of hepatic complications, ranging from ascites to fulminant liver failure. For patients receiving radiation therapy, cirrhosis dramatically reduces the already limited radiation tolerance of the liver and represents the most important clinical risk factor for the development of radiation-induced liver disease. Although improvements in conformal radiation delivery techniques have improved our ability to safely irradiate confined areas of the liver to increasingly higher doses with excellent local disease control, patients with moderate-to-severe liver cirrhosis continue to face a shortage of treatment options for HCC. In recent years, evidence has emerged supporting the use of bone marrow-derived stromal cells (BMSCs) as a promising treatment for liver cirrhosis, with several clinical studies demonstrating sustained improvement in clinical parameters of liver function after autologous BMSC infusion. Three predominant populations of BMSCs, namely hematopoietic stem cells, mesenchymal stem cells, and endothelial progenitor cells, seem to have therapeutic potential in liver injury and cirrhosis. Preclinical studies of BMSC transplantation have identified a range of mechanisms through which these cells mediate their therapeutic effects, including hepatocyte transdifferentiation and fusion, paracrine stimulation of hepatocyte proliferation, inhibition of activated hepatic stellate cells, enhancement of fibrolytic matrix metalloproteinase activity, and neovascularization of regenerating liver. By bolstering liver function in patients with underlying Child's B or C cirrhosis, autologous BMSC infusion holds great promise as a therapy to improve the safety, efficacy, and utility of surgery, chemotherapy, and hepatic radiation therapy in the treatment of HCC.

Dosimetric comparison of intensity modulated and volumetric arc radiation therapy for gastric cancer

The aim of the present study was to compare radiotherapy treatment plans for gastric cancer using intensity-modulated radiotherapy (IMRT) and single/double-arc volumetric modulated arc therapy (SA/DA-VMAT) delivery techniques. A total of 29 postoperative gastric cancer patients were enrolled in this study and each patient was scheduled 5-field IMRT (5F-IMRT), 7-field IMRT (7F-IMRT), SA-VMAT and DA-VMAT techniques. Dose-volume histogram statistics, conformal index (CI), homogeneity index (HI) and monitor units (MUs) were analyzed to compare treatment plans. The DA-VMAT plans exceeded the other three methods in terms of planning tumor volume dose and organs at risk in the kidneys, but not in the liver. DA-VMAT exhibited a better mean CI (0.87±0.03) and HI (0.10±0.01) than the other techniques. In addition, for the kidneys the dose sparing (V13, V18 and mean kidney dose) was improved by DA-VMAT plans. Similar results were observed for MUs. However, 5F-IMRT showed a marginal advantage in V30 and mean dose in normal liver when compared with DA-VMAT. The results of this study suggest that DA-VMAT provides improved tumor coverage when compared with 5F-IMRT, 7F-IMRT and SA-VMAT; however, DA-VMAT exhibits no advantage in liver protection when compared with 5F-IMRT. Further studies are required to establish differences in treatment outcomes among the four technologies.

Long-term pathological and immunohistochemical features in the liver after intraoperative whole-liver irradiation in rats

Radiation therapy (RT) has become particularly important recently for treatment of liver tumors, but there are few experimental investigations pertaining to radiation-induced liver injuries over long-term follow-up periods. Thus, the present study examined pathological liver features over a 10-month period using an intraoperative whole-liver irradiation model. Liver function tests were performed in blood samples, whereas cell death, cell proliferation, and fibrotic changes were evaluated pathologically in liver tissues, which were collected from irradiated rats 24 h, 1, 2, 4 and 40 weeks following administration of single irradiation doses of 0 (control), 15 or 30 Gy. The impaired liver function, increased hepatocyte number, and decreased apoptotic cell proportion observed in the 15 Gy group, but not the 30 Gy group, returned to control group levels after 40 weeks; however, the Ki-67 indexes in the 15 Gy group were still higher than those in the control group after 40 weeks. Azan staining showed a fibrotic pattern in the irradiated liver in the 30 Gy group only, but the expression levels of alpha smooth muscle actin (α-SMA) and transforming growth factor-beta 1 (TGF-β1) in both the 15 and 30 Gy groups were significantly higher than those in the control group (P < 0.05). There were differences in the pathological features of the irradiated livers between the 15 Gy and 30 Gy groups, but TGF-β1 and α-SMA expression patterns supported the gradual progression of radiation-induced liver fibrosis in both groups. These findings will be useful in the future development of protective drugs for radiation-induced liver injury.

Integrating respiratory-gated PET-based target volume delineation in liver SBRT planning, a pilot study

Background

To assess the feasibility and benefit of integrating four-dimensional (4D) Positron Emission Tomography (PET) – computed tomography (CT) for liver stereotactic body radiation therapy (SBRT) planning.

Methods

8 patients with 14 metastases were accrued in the study. They all underwent a non-gated PET and a 4D PET centered on the liver. The same CT scan was used for attenuation correction, registration, and considered the planning CT for SBRT planning. Six PET phases were reconstructed for each 4D PET. By applying an individualized threshold to the 4D PET, a Biological Internal Target Volume (BITV) was generated for each lesion. A gated Planning Target Volume (PTVg) was created by adding 3 mm to account for set-up margins. This volume was compared to a manual Planning Target Volume (PTV) delineated with the help of a semi-automatic Biological Target Volume (BTV) obtained from the non-gated exam. A 5 mm radial and a 10 mm craniocaudal margins were applied to account for tumor motion and set-up margins to create the PTV.

Results

One undiagnosed liver metastasis was discovered thanks to the 4D PET. The semi-automatic BTV were significantly smaller than the BITV (p = 0.0031). However, after applying adapted margins, 4D PET allowed a statistically significant decrease in the PTVg as compared to the PTV (p = 0.0052).

Conclusions

In comparison to non-gated PET, 4D PET may better define the respiratory movements of liver targets and improve SBRT planning for liver metastases. Furthermore, non respiratory-gated PET exams can both misdiagnose liver metastases and underestimate the real internal target volumes.

Estimating functional liver reserve following hepatic irradiation: adaptive normal tissue response models

PURPOSE

To estimate the limit of functional liver reserve for safe application of hepatic irradiation using changes in indocyanine green, an established assay of liver function.

MATERIALS AND METHODS

From 2005 to 2011, 60 patients undergoing hepatic irradiation were enrolled in a prospective study assessing the plasma retention fraction of indocyanine green at 15-min (ICG-R15) prior to, during (at 60% of planned dose), and after radiotherapy (RT). The limit of functional liver reserve was estimated from the damage fraction of functional liver (DFL) post-RT [1-(ICG-R15pre-RT/ICG-R15post-RT)] where no toxicity was observed using a beta distribution function.

RESULTS

Of 48 evaluable patients, 3 (6%) developed RILD, all within 2.5 months of completing RT. The mean ICG-R15 for non-RILD patients pre-RT, during-RT and 1-month post-RT was 20.3%(SE 2.6), 22.0%(3.0), and 27.5%(2.8), and for RILD patients was 6.3%(4.3), 10.8%(2.7), and 47.6%(8.8). RILD was observed at post-RT damage fractions of ≥78%. Both DFL assessed by during-RT ICG and MLD predicted for DFL post-RT (p<0.0001). Limiting the post-RT DFL to 50%, predicted a 99% probability of a true complication rate <15%.

CONCLUSION

The DFL as assessed by changes in ICG during treatment serves as an early indicator of a patient's tolerance to hepatic irradiation.

Phase 2 study of combined sorafenib and radiation therapy in patients with advanced hepatocellular carcinoma

PURPOSE

This phase 2 study evaluated the efficacy of radiation therapy (RT) with concurrent and sequential sorafenib therapy in patients with unresectable hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

Forty patients with unresectable HCC unfit for transarterial chemoembolization were treated with RT with concurrent and sequential sorafenib. Sorafenib was administered from the commencement of RT at a dose of 400 mg twice daily and continued to clinical or radiologic progression, unacceptable adverse events, or death. All patients had underlying Child-Pugh A cirrhosis. The maximal tumor diameter ranged from 3.0 cm to 15.5 cm. Coexisting portal vein thrombosis was found in 24 patients and was irradiated simultaneously. The cumulative RT dose ranged from 40 Gy to 60 Gy (median, 50 Gy). Image studies were done 1 month after RT and then every 3 months thereafter.

RESULTS

Thirty-three (83%) completed the allocated RT. During RT, the incidence of hand-foot skin reactions ≥ grade 2 and diarrhea were 37.5% and 25%, respectively, and 35% of patients had hepatic toxicities grade ≥2. Twenty-two (55.0%) patients achieved complete or partial remission at the initial assessment, and 18 (45%) had stable or progressive disease. The 2-year overall survival and infield progression-free survival (IFPS) were 32% and 39%, respectively. A Cancer of the Liver Italian Program (CLIP) score ≥2 was associated with an inferior outcome in overall survival. Six patients (15%) developed treatment-related hepatic toxicity grade ≥3 during the sequential phase, and 3 of them were fatal.

CONCLUSIONS

When RT and sorafenib therapy were combined in patients with unresectable HCC, the initial complete or partial response rate was 55% with a 2-year IFPS of 39%. A CLIP score ≥2 was associated with an inferior outcome in overall survival. Hepatic toxicities are a major determinant of the safety; the combination should be used with caution and needs further investigation.

Therapeutic benefit of radiotherapy in huge (≥10 cm) unresectable hepatocellular carcinoma

BACKGROUND & AIMS

Huge (≥10 cm) hepatocellular carcinomas (HCCs) show dismal prognosis and only a limited number of cases are eligible for curative resection. We studied the therapeutic benefit of radiotherapy (RT) in patients with huge unresectable HCCs.

METHODS

Data from 283 patients with huge HCCs and preserved liver function who underwent non-surgical treatment from July 2001 to March 2012 were retrospectively reviewed. Patients were divided into 4 groups according to the initial treatment: Group A (N= 49), transarterial chemoembolization (TACE); Group B (N = 35), TACE + RT; Group C (N = 50), hepatic arterial infusion chemotherapy; and Group D (n = 149), concurrent chemoradiotherapy (CCRT).

RESULTS AND CONCLUSIONS

The median follow-up period was 27.8 months (range, 12.9-121.9 months). The median overall survival (OS) was longer in Groups B (15.3 months) and D (12.8 months) than in Groups A (7.5 months) and C (8.2 months; Group B vs. A, Bonferroni corrected P [P(c)] = 0.04; Group B vs. C, P(c) = 0.02; Group D vs. A, P(c) = 0.01; Group D vs. C, Pc = 0.006). Groups B and D also showed superior progression-free survival (PFS) and intrahepatic control than Groups A and C. In multivariate analysis, tumour multiplicity, serum alpha-foetoprotein level (≥200 ng/ml) and initial treatment were independent prognostic factors for OS and PFS. Patients with huge unresectable HCCs treated with RT, either as CCRT or in combination with TACE, showed excellent intrahepatic control and prolonged survival. RT could be considered a promising treatment modality in these patients.

Stereotactic ablative radiotherapy for oligometastatic disease in liver

Liver metastasis in solid tumors, including colorectal cancer, is the most frequent and lethal complication. The development of systemic therapy has led to prolonged survival. However, in selected patients with a finite number of discrete lesions in liver, defined as oligometastatic state, additional local therapies such as surgical resection, radiofrequency ablation, cryotherapy, and radiotherapy can lead to permanent local disease control and improve survival. Among these, an advance in radiation therapy made it possible to deliver high dose radiation to the tumor more accurately, without impairing the liver function. In recent years, the introduction of stereotactic ablative radiotherapy (SABR) has offered even more intensive tumor dose escalation in a few fractions with reduced dose to the adjacent normal liver. Many studies have shown that SABR for oligometastases is effective and safe, with local control rates widely ranging from 50% to 100% at one or two years. And actuarial survival at one and two years has been reported ranging from 72% to 94% and from 30% to 62%, respectively, without severe toxicities. In this paper, we described the definition and technical aspects of SABR, clinical outcomes including efficacy and toxicity, and related parameters after SABR in liver oligometastases from colorectal cancer.

Significance of an increase in the Child-Pugh score after radiotherapy in patients with unresectable hepatocellular carcinoma

Background

We attempted to analyze the effects of an increase in the Child-Pugh (CP) score on the overall survival of patients with unresectable hepatocellular carcinoma (HCC) after radiotherapy (RT).

Methods

From March 2006 to February 2012, 103 patients received RT using the TomoTherapy Hi-Art at Incheon St. Mary’s Hospital and Seoul St. Mary’s Hospital. The dose per fraction was 1.8–5 Gy, and the total dose was 40–60 Gy (median, 50 Gy). We considered an increase of at least 2 points in the CP score within 3 months after RT to be clinically important radiation-induced hepatic toxicity and analyzed the effects of an increased CP score on overall survival.

Results

The median follow-up duration was 11.6 months (range, 3.5–85.3 months). The median survival time was 11.6 months. In multivariate analysis, planning target volume and an increase in the CP score after RT were found to be a statistically significant factors (p = 0.010 and 0.015, respectively). In a comparison of cases with and without an increase in the CP score, there was an 11.0-month difference in the median survival time (6.9 vs. 17.9 months), and the relative risk of mortality was 1.8.

Conclusion

An increase of at least 2 points in the CP score within 3 months of RT completion is an important on-treatment factor that affects overall survival. To minimize such increases, careful patient selection and a more sophisticated radiation treatment plan are imperative.

Risk factors for hepatitis B virus reactivation after conformal radiotherapy in patients with hepatocellular carcinoma

This study investigated whether conformal radiotherapy affects hepatitis B virus (HBV) reactivation, and the risk factors for HBV reactivation in patients with HBV-related hepatocellular carcinoma (HCC). Sixty-nine patients with HCC were included in this retrospective study. Before radiotherapy (RT), all patients underwent imaging examinations and some baseline examinations, including CBC, liver function test, renal function test, α-fetoprotein level, hepatitis B (HB) surface antigen, HB surface Ab, HB e antigen, HB e Ab, and serum HBV DNA quantification. During the period of RT and at least 16 weeks after the end of RT, CBCs were carried out weekly and the other tests were monitored monthly or more frequently if necessary. The clinical features and dosimetric parameters of RT were recorded. Univariate and multivariate logistic regression algorithms were used to analyze the risk factors of HBV reactivation. The incidence of complications in the study population was as follows: radiation-induced liver disease, 17.4%; HBV reactivation, 24.6%; and HBV reactivation-induced hepatitis, 21.7%. The HBV DNA level and dose volume parameters including normal liver volume, V20, and mean dose were associated with HBV reactivation. There was a relatively high incidence of HBV reactivation in HCC patients after the end of conformal RT. The serum HBV DNA level and some dosimetric parameters related to normal liver, including normal liver volume, V20, and mean dose, were the prognosis factors of HBV reactivation and should be carefully considered before conformal RT.

A comparison of liver protection among 3-D conformal radiotherapy, intensity-modulated radiotherapy and RapidArc for hepatocellular carcinoma

Purpose

The analysis was designed to compare dosimetric parameters among 3-D conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT) and RapidArc (RA) to identify which can achieve the lowest risk of radiation-induced liver disease (RILD) for hepatocellular carcinoma (HCC).

Methods

Twenty patients with HCC were enrolled in this study. Dosimetric values for 3DCRT, IMRT, and RA were calculated for total dose of 50 Gy/25f. The percentage of the normal liver volume receiving >40, >30, >20, >10, and >5 Gy (V₄₀, V₃₀, V₂₀, V₁₀ and V₅) were evaluated to determine liver toxicity. V₅, V₁₀, V₂₀, V₃₀ and D_mean of liver were compared as predicting parameters for RILD. Other parameters included the conformal index (CI), homogeneity index (HI), and hot spot (V_110%) for the planned target volume (PTV) as well as the monitor units (MUs) for plan efficiency, the mean dose (D_mean) for the organs at risk (OARs) and the maximal dose at 1% volume (D_1%) for the spinal cord.

Results

The D_mean of IMRT was higher than 3DCRT (p = 0.045). For V₅, there was a significant difference: RA > IMRT >3DCRT (p <0.05). 3DCRT had a lower V₁₀ and higher V₂₀, V₃₀ values for liver than RA (p <0.05). RA and IMRT achieved significantly better CI and lower V_110% values than 3DCRT (p <0.05). RA had better HI, lower MUs and shorter delivery time than 3DCRT or IMRT (p <0.05).

Conclusion

For right lobe tumors, RapidArc may have the lowest risk of RILD with the lowest V₂₀ and V₃₀ compared with 3DCRT or IMRT. For diameters of tumors >8 cm in our study, the value of D_mean for 3DCRT was lower than IMRT or RapidArc. This may indicate that 3DCRT is more suitable for larger tumors.

Radiation-induced liver disease after stereotactic body radiotherapy for small hepatocellular carcinoma: clinical and dose-volumetric parameters

Background

To investigate the clinical and dose–volumetric parameters that predict the risk of radiation-induced liver disease (RILD) for patients with small, unresectable hepatocellular carcinoma (HCC) treated with stereotactic body radiotherapy (SBRT).

Methods

Between March 2007 and December 2009, 92 patients with HCC treated with SBRT were reviewed for RILD within 3 months of completing treatment. RILD was evaluated according to the Common Terminology Criteria for Adverse Events, version 3.0. A dose of 10–20 Gy (median, 15 Gy) per fraction was given over 3–4 consecutive days for a total dose of 30–60 Gy (median, 45 Gy). The following clinical and dose–volumetric parameters were examined: age, gender, Child-Pugh class, presence of hepatitis B virus, gross tumor volume, normal liver volume, radiation dose, fraction size, mean dose to the normal liver, and normal liver volumes receiving from < 5 Gy to < 60 Gy (in increments of 5 Gy).

Results

Seventeen (18.5%) of the 92 patients developed grade 2 or worse RILD after SBRT (49 patients in grade 1, 11 in grade 2, and 6 in ≥ grade 3). On univariate analysis, Child-Pugh class was identified as a significant clinical parameter, while normal liver volume and normal liver volumes receiving from < 15 Gy to < 60 Gy were the significant dose–volumetric parameters. Upon multivariate analysis, only Child-Pugh class was a significant parameter for predicting grade 2 or worse RILD.

Conclusions

The Child-Pugh B cirrhosis was found to have a significantly greater susceptibility to the development of grade 2 or worse RILD after SBRT in patients with small, unresectable HCC. Additional efforts aimed at testing other models to predict the risk of RILD in a large series of HCC patients treated with SBRT are needed.

High-dose hypofractionated X-ray radiotherapy for hepatocellular carcinoma: Tumor responses and toxicities

Hypofractionated radiotherapy (RT) has been employed to treat hepatocellular carcinoma (HCC). The present study aimed to report the treatment effects, the dose-response associations and the factors that are associated with radiation-induced liver disease (RILD) in a high-dose hypofractionated RT procedure. A total of 40 patients with non-metastatic HCC who underwent RT for local control of irradiated tumors were studied. The treatment technique was that of three-dimensional conformal or intensity-modulated radiation therapy, with a fraction size of 3 Gy and a total dose of 40–66 Gy in 14–23 fractions. The biologically-effective dose (BED) was 52.0–85.8 Gy₁₀ (median, 74.1 Gy₁₀). Tumor regression was observed in 28 patients (70.0%) with a complete response, partial response, stable disease and progressive disease status in 11 (27.5%), 17 (42.5%), five (12.5%) and seven patients (17.5%), respectively. The one-, two- and five-year overall survival (OS) and in-field control (IFC) rates were 60, 40 and 21% and 73, 62 and 56%, respectively. A positive correlation also emerged between the radiation dose and the IFC (P=0.035). Eight of the 40 patients (20%) developed non-classic RILD. A higher Cancer of the Liver Italian Program score was associated with a higher probability of non-classic RILD (P=0.02). The tumor response and IFC rate of HCC following irradiation were significantly dose-dependent. High-dose hypofractionated X-ray RT is a feasible and effective treatment for HCC in patients with good liver function and for those who meet the criteria for a curative attempt.

Liver injury induced by anticancer chemotherapy and radiation therapy

Cytotoxic chemotherapy prolongs survival of patients with advanced and metastatic tumors. This is, however, a double-edged sword with many adverse effects. Since the liver has a rich blood supply and plays an active role in the metabolism of medications, it is not surprising that there can be hepatic injury related to chemotherapy. In addition, radioembolization may affect the parenchyma of normal and cirrhotic livers. We review chemotherapy-associated liver injury in patients with colorectal liver metastases, including downsizing chemotherapy and neoadjuvant chemotherapy. We discuss the mechanism of the hepatic injury, secondary to reactive oxygen species, and the spectrum of hepatic injury including, steatosis, steatohepatitis, hepatic sinusoidal injury and highlight the pharmacogenomics of such liver insults. Methods for reducing and treating the hepatotoxicity are discussed for specific agents including tamxifen and the newly introduced targeted antibodies.

A dose-volume intercomparison of volumetric-modulated arc therapy, 3D static conformal, and rotational conformal techniques for portal vein tumor thrombus in hepatocellular carcinoma

We created volumetric-modulated arc therapy (VMAT) plans for portal vein tumor thrombus (PVTT) in hepatocellular carcinoma, and compared the results with those from three-dimensional conformal radiotherapy (3D-CRT) and rotational conformal radiotherapy (R-CRT) plans. CT scan data from 10 consecutive patients with PVTT treated with 3D-CRT between January 2008 and January 2010 were utilized in the analysis. We analyzed the dosimetric properties of the plans for the 10 patients using the three different techniques with three different isocenter doses of 50, 56 and 60 Gy in 2-Gy fractions. The D95, Dmean, homogeneity index and conformity index were compared for the planning target volume (PTV). The Dmean, V20 and V30 were also compared for normal livers. The monitor units (MUs) and the treatment time were also evaluated. The normal liver V30 for VMAT was significantly less than that for 3D-CRT for the prescribed doses of 56 and 60 Gy (P < 0.05). It was also found that the normal liver V30 resulting from 3D-CRT was prohibitively increased when the prescribed dose was increased in two steps. For PTV D95, we found no significant differences between the three techniques for the 50- and 56-Gy prescriptions, or between VMAT and the other techniques for the 60-Gy prescription. The differences in the MUs and treatment times were not statistically significant between VMAT and 3D-CRT. We have demonstrated that VMAT may be a more advantageous technique for dose escalation reaching 60 Gy in the treatment of PVTT due to the reduced normal liver V30.

Superior liver sparing by combined coplanar/noncoplanar volumetric-modulated arc therapy for hepatocellular carcinoma: a planning and feasibility study

Compared with step-and-shoot intensity-modulated radiotherapy (sIMRT) and tomotherapy, volumetric-modulated arc therapy (VMAT) allows additional arc configurations in treatment planning and noncoplanar (NC) delivery. This study was first to compare VMAT planning with sIMRT planning, and the second to evaluate the toxicity of coplanar (C)/NC-VMAT treatment in patients with hepatocellular carcinoma (HCC). Fifteen patients with HCC (7 with left-lobe and 8 with right-lobe tumors) were planned with C-VMAT, C/NC-VMAT, and sIMRT. The median total dose was 49Gy (range: 40 to 56Gy), whereas the median fractional dose was 3.5Gy (range: 3 to 8Gy). Different doses/fractionations were converted to normalized doses of 2Gy per fraction using an α/β ratio of 2.5. The mean liver dose, volume fraction receiving more than 10Gy (V10), 20Gy (V20), 30Gy (V30), effective volume (Veff), and equivalent uniform dose (EUD) were compared. C/NC-VMAT in 6 patients was evaluated for delivery accuracy and treatment-related toxicity. Compared with sIMRT, both C-VMAT (p = 0.001) and C/NC-VMAT (p = 0.03) had significantly improved target conformity index. Compared with C-VMAT and sIMRT, C/NC-VMAT for treating left-lobe tumors provided significantly better liver sparing as evidenced by differences in mean liver dose (p = 0.03 and p = 0.007), V10 (p = 0.003 and p = 0.009), V20 (p = 0.006 and p = 0.01), V30 (p = 0.02 and p = 0.002), Veff (p = 0.006 and p = 0.001), and EUD (p = 0.04 and p = 0.003), respectively. For right-lobe tumors, there was no difference in liver sparing between C/NC-VMAT, C-VMAT, and sIMRT. In all patients, dose to more than 95% of target points met the 3%/3mm criteria. All 6 patients tolerated C/NC-VMAT and none of them had treatment-related ≥ grade 2 toxicity. The C/NC-VMAT can be used clinically for HCC and provides significantly better liver sparing in patients with left-lobe tumors.

Determination of the α/β ratio for the normal liver on the basis of radiation-induced hepatic toxicities in patients with hepatocellular carcinoma

Background

The purpose of this study was to determine the α/β ratio for normal liver with hepatitis by analyzing the toxicity data from patients with unresectable hepatocellular carcinoma treated with helical tomotherapy.

Methods

Between March 2006 and February 2012, 98 patients were eligible for this study. 66 patients received 45–50 Gy in 4.5-5 Gy fractions (Group A) and 32 patients received 36–60 Gy in 2.5-3 Gy fractions (Group B). Radiation-induced hepatic toxicity was defined as an increase of at least 2 points in the Child-Pugh score within 4 months of completing helical tomotherapy. We attempted to find the statistically significant parameters in the 2 groups using α/β ratios of 2, 4, 6, 8, or 10, and compared the estimated probability curves of each significant parameter. We hypothesized that the α/β ratio associated with the best matches for the curves between the 2 groups would be equivalent to the α/β ratio for the normal liver.

Results

When using an α/β ratio of 2 or 4, different parameters were found to be statistically significant in a multivariate analysis (Group A: V_BED30 for α/β ratio = 2 and V_BED25 for α/β ratio = 4, Group B: V_BED25 for α/β ratio = 2 and V_BED20 for α/β ratio = 4). When using an α/β ratio of 6, 8, or 10, V_BED20 was found to be a statistically significant parameter in both groups. Comparison of the estimated probability curve of each significant parameter between the groups revealed that an α/β ratio of 8 resulted in the best matches.

Conclusions

We suggest that the α/β ratio of the normal liver with hepatitis is 8. We hope that previously reported parameters and their values can be effectively used in different fractionation schemes by calculating the biologically effective dose using an α/β ratio of 8.

A method for registration of single photon emission computed tomography (SPECT) and computed tomography (CT) images for liver stereotactic radiotherapy (SRT)

PURPOSE

To describe a simple method of coregistration of nonanatomic liver SPECT and CT images acquired in separate sessions for three-dimensional (3D)-CRT planning utilizing dual radiolabeled and radiopaque body surface markers, and evaluate the accuracy of the registration on the patient surface.

METHODS

Ten patients treated for liver metastases or hepatocellular carcinoma with stereotactic body radiation therapy or 3D-CRT were selected for this study to evaluate the SPECT∕CT registration process. All patients were positioned in a custom-molded vacuum bag on the flat table top. Nine radiopaque markers were taped to the abdominal surface in three axial planes at the level of the liver. Following CT imaging, the nine radiopaque markers were then labeled with radioactive tags, each containing 10 μCi of (99m)Tc, and SPECT images were acquired. The metric used to evaluate the registration was the fiducial registration error (FRE), defined as the root mean square of the distance between pairs of homologous markers on the CT and SPECT images. The evaluation of the registration accuracy was performed in two steps: first the minimum number of markers necessary to obtain a robust registration was optimized; second the FRE was calculated on the remaining set of unused markers. Additionally, the deformation of the patient's abdominal surface between CT and SPECT acquisition sessions was evaluated using the distances between all possible unused marker pairs on the CT and SPECT images separately. The root mean square of the CT-to-SPECT difference between those distances was used to define the deformation index (DI). The registration method was evaluated on all ten patients in addition to an anthropomorphic phantom study.

RESULTS

The minimum number of markers above which the registration was not improved by more than 1 mm was 4. The FRE, calculated over the 5 remaining markers, was 6.1 mm for the patient population and 1.8 mm for the phantom study. The DI was 5.0 mm on average over all 10 patients and correlated well with the FRE. The DI was 1.6 mm for the phantom study, which represented the imaging systems' resolution and the ability to place the CT and SPECT markers at the exact same location.

CONCLUSIONS

It is feasible to use radiolabeled and radiopaque dual body surface markers for registration of SPECT and CT images acquired in separate sessions allowing conformal avoidance of SPECT-defined functional normal liver. Point-based rigid registration accuracy on the patient surface of 6.1 mm can be achieved using 4 dual body surface markers. The main contribution to the registration error is the deformation of the abdominal surface, arising from the inability to setup the patient in the exact same position at different times on two different imaging systems, and to properly account for breathing artifacts on the CT and SPECT images.

Stereotactic body radiation therapy combined with transcatheter arterial chemoembolization for small hepatocellular carcinoma

BACKGROUND AND AIMS

To compare the tumor control and safety of stereotactic body radiation therapy (SBRT) combined with transcatheter arterial chemoembolization (TACE) for small, solitary, and hypervascular hepatocellular carcinoma (HCC) with TACE alone.

METHODS

Three hundred and sixty-five HCC patients who had solitary, ≤ 3 cm, and hypervascular nodule were treated with TACE. Among them, 30 patients followed by SBRT (SBRT group) and 38 patients without additional therapy and previous HCC treatment (control group) were enrolled in this retrospective cohort study. Local tumor progression, complication, and disease-free survival were compared between these groups.

RESULTS

There was no difference in clinical background between these groups. Complete response to therapy was noted in 29 (96.3%) patients of the SBRT group, and in only one (3.3%) patient of the TACE group (P < 0.001). None of the patients developed acute hematologic toxicity of more than Common Terminology Criteria for Adverse Events Grade 3 during and after the treatment. Furthermore, none of the SBRT group developed radiation-induced liver damage. Disease-free survival of the 12 patients without previous HCC treatments in SBRT group was significantly superior to that in control group (15.7 months vs 4.2 months; P = 0.029).

CONCLUSION

The results indicated that SBRT combined with TACE is a safe and effective modality for locoregional treatment of small solitary primary HCC, and could be potentially a suitable option.

Dosimetric parameter predicting the deterioration of hepatic function after helical tomotherapy in patients with unresectable locally advanced hepatocellular carcinoma

BACKGROUND

The purpose of this study was to identify parameters capable of predicting the deterioration of hepatic function after helical tomotherapy in patients with unresectable locally advanced hepatocellular carcinoma.

METHODS

Between March 2006 and February 2012, 72 patients were eligible for this study. All patients received hypofractionated radiotherapy using the TomoTherapy Hi-Art (TomoTherapy, Madison, WI, USA) at Seoul St. Mary's Hospital and Incheon St. Mary's Hospital, the Catholic University of Korea. The radiation dose was a median 50 Gy (range: 40-50 Gy) in 10 fractions to 95% of the planning target volume. Radiation-induced hepatic toxicity was defined as an increase of at least 2 points in the Child-Pugh (CP) score within 3 months after completion of helical tomotherapy.

RESULTS

An increase of at least 2 points in the CP score occurred in 32 of the 72 patients (44.4%). Multivariate logistic regression analysis revealed that pretreatment CP class and V15Gy were significant parameters associated with an increase in CP score (p = 0.009 and p < 0.001, respectively). The area under receiver operating characteristic curve was 0.863 for V15Gy (p < 0.001). For V15Gy, with a cutoff value of 43.2%, the accuracy was 0.806 (58/72) with a sensitivity of 0.938 and a specificity of 0.725.

CONCLUSIONS

An increase of at least 2 points in the CP score is a radiation dose-limiting factor, and the non-target normal liver receiving a dose more than 15 Gy (V15Gy) should be <43.2% to reduce the risk of the deterioration of hepatic function.

Hepatic dysfunction after radiotherapy for primary gastric lymphoma

Patients with primary gastric lymphoma (PGL) are often treated with three-dimensional conformal radiotherapy (3D-CRT) in three to four fields to reduce the dose to the left kidney. However, the liver dose is higher than conventional parallel-opposed fields. This study was designed to evaluate hepatic dysfunction after 3D-CRT in patients with PGL. The data of 20 PGL patients treated with 3D-CRT were analyzed. Of the 20 patients, 3 had mucosa-associated lymphoid tissue (MALT) lymphoma and 17 had diffuse large B-cell lymphoma (DLBCL). The median dose used to treat MALT lymphoma was 30 Gy and 40 Gy for DLBCL. Pretreatment and post-treatment transaminase and alkaline phosphatase (ALP) values were compared. Radiation-induced hepatic dysfunction (RIHD) was defined as a more than 2-fold increase in transaminase or ALP levels, exceeding the upper limit within 4 months of the completion of radiotherapy. Increased transaminase or ALP levels were observed in 19 patients (95%). RIHD was observed in 14 patients (70%). The transaminase and ALP values were significantly different between pretreatment and post-treatment. There were significant differences in liver volumes receiving ≥5, ≥10, ≥15 and ≥20 Gy (V5, V10, V15 and V20) and in the mean liver doses between patients with and without RIHD. For patients with V10 > 60%, V15 > 50% or V20 > 30% in particular, the incidence rates of RIHD were significantly high. After radiotherapy for PGL, hepatic dysfunction occurred at a high rate. Thus, radiotherapy treatment should be planned in order to reduce liver doses.

Radioprotective role of H(2)S/CSE pathway in Chang liver cells

Radiation-induced liver cell damage may be life-threatening. Here, we investigated whether hydrogen sulfide (H(2)S)/cystathionine γ-lyase (CSE) pathway could serve the protective role toward radiation in normal human liver cells. Our data showed that pretreatment of cells with H(2)S donor, sodium hydrosulfide (NaHS) significantly attenuated radiation induced micronuclei formation and improved cell viability. However, the use of dl-propargylglycine (PPG), a potent inhibitor of CSE, markedly enhanced the cell-killing effect induced by radiation. Exposure of cells to 2Gy γ-radiation led to significant increases of the endogenous H(2)S content. The mRNA and protein expressions of CSE also increased after radiation in a time-dependent manner, while the expression of cystathionine β-synthase (CBS), another endogenous H(2)S synthetase, did not change significantly. Notably, radiation induced production of reactive oxygen species (ROS) was significantly reversed by the pretreatment of NaHS, while blockage of CSE activity resulted in an enhanced ROS production in irradiated cells. Moreover, NaHS markedly suppressed radiation-induced phosphorylation of P53, decrease of Bcl-2/Bax, and activity of nuclear factor kappaB (NF-κB). In conclusion, our finding demonstrates that H(2)S/CSE pathway plays a radioprotection role by inhibiting radiation-induced ROS production, P53 phosphorylation, NF-κB activation and decrease of Bcl-2/Bax, indicating that modulation of H(2)S may be a novel protection strategy for liver radiation injury in radiotherapy.

Hepatic radiation toxicity: avoidance and amelioration

The refinement of radiation therapy and radioembolization techniques has led to a resurgent interest in radiation-induced liver disease (RILD). The awareness of technical and clinical parameters that influence the chance of RILD is important to guide patient selection and toxicity minimization strategies. "Classic" RILD is characterized by anicteric ascites and hepatomegaly and is unlikely to occur after a mean liver dose of approximately 30 Gy in conventional fractionation. By maintaining a low mean liver dose and sparing a "critical volume" of liver from radiation, stereotactic delivery techniques allow for the safe administration of higher tumor doses. Caution must be exercised for patients with hepatocellular carcinoma or pre-existing liver disease (eg, Child-Pugh score of B or C) because they are more susceptible to RILD that can manifest in a nonclassic pattern. Although no pharmacologic interventions have yet been proven to mitigate RILD, preclinical research shows the potential for therapies targeting transforming growth factor-β and for the transplantation of stem cells, hepatocytes, and liver progenitor cells as strategies that may restore liver function. Also, in the clinical setting of veno-occlusive liver disease after high-dose chemotherapy, agents with fibrinolytic and antithrombotic properties can reverse liver failure, suggesting a possible role in the setting of RILD.

Radiation therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide, and its incidence is on the rise. The primary therapy is resection or liver transplant, but only a minority of patients present with resectable disease. Historically, radiotherapy has not played a significant role in the treatment of liver malignancies because of the low tolerance of the whole liver to radiation. With improvements in 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy, higher doses of radiation can be delivered to target lesions with low doses to the noninvolved liver; thus, experience in the use of radiation for the treatment of focal HCC has increased. At the same time, our understanding of the relationships between radiation dose and volume and the risk of classic radiation-induced liver disease and other toxicities more likely to occur in HCC patients has improved considerably. These developments have led to a body of evidence that now supports the careful use of radiotherapy for unresectable HCC. The rationale for studying radiotherapy in a randomized trial is strong.

Dose volume histogram analysis of focal liver reaction in follow-up multiphasic CT following stereotactic body radiotherapy for small hepatocellular carcinoma

PURPOSE

To investigate threshold dose (TD) of focal liver reaction (FLR) following stereotactic body radiotherapy (SBRT) for patients with hepatocellular carcinoma (HCC) and liver cirrhosis.

MATERIALS AND METHODS

In consecutive 50 patients receiving SBRT for small HCC, 38 patients receiving SBRT and follow up >6 months, FLR on follow-up CT had been previously studied. Patients with good concordance between FLR and highly irradiated area were eligible. Dose volume histogram (DVH) was used to identify TDs for FLR. Clinical factors were analyzed for correlation with TDs.

RESULTS

Of 24 eligible patients, 23 had Child-Pugh score A and 1 scored B. Presence of FLR peaked at a median of 6 (range; 3-12) months. The median and 95% confidential intervals of TDs of pre-contrast and portal-venous phase CT were 32.4 Gy (30.3-35.4) and 34.4 Gy (31.9-36.0), respectively. Each median coefficient representing the concordance was 74.9% (range; 55.8-98.0%) and 80.5% (range; 70.8-92.4%), respectively. No clinical factors significantly correlated with the TDs.

CONCLUSION

We proposed 30 Gy/5 fractions as TD of FLRs following SBRT for patients with HCC and liver cirrhosis. This TD will enable us to predict injured liver volume and to avoid complication beforehand from toxicity. Further pathological and clinical studies, in addition to more practical and precise data of DVH, are needed to clarify the significance of FLRs.