Dosimetric analysis and comparison of three-dimensional conformal radiotherapy and intensity-modulated radiation therapy for patients with hepatocellular carcinoma and radiation-induced liver disease

Dosimetric study of three-dimensional static and dynamic SBRT radiotherapy for hepatocellular carcinoma based on 4DCT image deformable registration

The purpose of this work was to determine the actual dose received by normal tissues during four‐dimensional radiation therapy (4DRT) composed of ten phases of four‐dimensional computer tomography (4DCT) images. The analysis was performed by tracking the hepatocellular carcinoma SBRT. Data were acquired from the tracking of each phase with the beam aperture for 28 hepatocellular carcinoma patients, and the data were used to generate a cumulative plan, which was compared to a three‐dimensional (3D) plan formed from a merged target volume based on 4DCT images in a radiation treatment planning system (TPS). The change in normal tissue dose was evaluated in the plan using the parameters V5, V10, V15, V20, V25, V30, V35, and V40 (volumes receiving 5, 10, 15, 20, 25, 30, 35, and 40 Gy, respectively) in the dose‐volume histogram for the liver; the mean dose was analyzed for the following tissues: liver, left kidney, and right kidney. The maximum dose was analyzed for the following tissues: bowel, duodenum, esophagus, stomach, and heart. There was a significant difference in the dose between the 4D planning target volume (PTV) (average 115.71 cm³) and ITV (169.86 cm³). The planning objective was for 95% of the volume of the PTV to be covered by the prescription dose, but the mean dose for the liver, left kidney and right kidney had an average decrease of 23.13%, 49.51%, and 54.38%, respectively. The maximum dose for the bowel, duodenum, esophagus, stomach, and heart had an average decrease of 16.77%, 28.07%, 24.28%, 4.89%, and 4.45%, respectively. Compared to 3D RT, the radiation volume for the liver V5, V10, V15, V20, V25, V30, V35, and V40 using the 4D plans had a significant decrease (P ﹤ 0.05). The 4D method creates plans that permit sparing of the normal tissues more than the commonly used ITV method, which delivers the same dosimetric effects to the target.

Efficacy and safety of external-beam radiation therapy for hepatocellular carcinoma: An overview of current evidence according to the different target population

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. During the recent years, external-beam radiation therapy (EBRT) has been safely and effectively employed for the management of HCC. We overviewed the current evidence regarding the efficacy and safety of EBRT for HCC according to the different target population. PubMed database was searched for identifying English-language full-text articles regarding EBRT for the treatment of HCC. Search items were "hepatocellular carcinoma AND radiation therapy". Until now, preliminary evidence has suggested the following role of EBRT for HCC. 1) EBRT, especially stereotactic body radiation therapy, is an emerging choice of therapy for small HCC. 2) EBRT combined with non-surgical treatment can achieve an excellent intrahepatic tumor control and a potential survival benefit for huge HCC. 3)Adjunctive EBRT may improve the efficacy of transarterial chemoembolization for HCC with portal vein tumor thrombosis. 4) EBRT can relieve the pain and improve the quality of life for patients with extrahepatic metastases. 5) EBRT may be a bridge to liver transplantation by minimizing the tumor progression. 6) Adjunctive EBRT may reduce the tumor recurrence and improve the survival after resection. In summary, EBRT is a promising choice of treatment of HCC. However, more high-quality evidence is needed to further establish the status of EBRT for the management of HCC.

Prognosticators of hepatocellular carcinoma with intrahepatic vascular invasion

OBJECTIVE

The prognosis of intrahepatic vascular invasion, including unilateral or main portal vein tumor thrombosis (PVTT) and hepatic vein thrombosis, is still poor. Many patients with intrahepatic vascular invasions never receive radiotherapy (RT). In recent years, more conformal RT techniques such as intensity-modulated RT (IMRT) have been developed and applied to treat other cancers and have significantly improved treatment results and decreased side effects. The purpose of this study is to evaluate the treatment results in patients with intrahepatic vascular invasion and explore the role of IMRT in these treatments.

MATERIALS AND METHODS

There were a total of 73 patients with newly diagnosed AJCC stage IIIB hepatocellular carcinoma (HCC), with either PVTT or hepatic vein tumor thrombosis between 2007 and 2015 in our hospital. IMRT was used for all patients who received RT. Prognostic factors, including treatment modalities, liver function, and comorbidities, were analyzed using univariate and multivariate analysis with the Cox model. Survival time was analyzed using the Kaplan-Meier method.

RESULTS

The longest follow-up time was 45.3 months. The median age was 67 years. Univariate analyses indicated that IMRT, transarterial chemoembolization (TACE), target therapy (sorafenib), tumor size, Child-Pugh class, and ascites were significantly associated with overall survival (OS). In multivariate analysis, IMRT (hazard ratio [HR], 0.495; P = 0.019), sorafenib (HR, 0.340; P = 0.013), tumor size (HR, 2.085; P = 0.020), and Child-Pugh class (P = 0.004), were independent prognostic predictors for patients with intrahepatic vessel invasion, but TACE and ascites were not. The outcomes of patients who had different treatment modalities were significantly different (P < 0.001). Patients who received IMRT with TACE had the best outcomes. Patients who received an RT dose above 5400 cGy had better outcomes than those who with a dose below 5400 cGy, although the results were not significantly different (P = 0.248).

CONCLUSION

IMRT is an important treatment component for patients with intrahepatic vascular invasion. Combined treatment modalities, such as IMRT with TACE, could improve the outcomes of HCC patients with intrahepatic vessel invasion.

Radiomics based analysis to predict local control and survival in hepatocellular carcinoma patients treated with volumetric modulated arc therapy

Background

To appraise the ability of a radiomics based analysis to predict local response and overall survival for patients with hepatocellular carcinoma.

Methods

A set of 138 consecutive patients (112 males and 26 females, median age 66 years) presented with Barcelona Clinic Liver Cancer (BCLC) stage A to C were retrospectively studied. For a subset of these patients (106) complete information about treatment outcome, namely local control, was available. Radiomic features were computed for the clinical target volume. A total of 35 features were extracted and analyzed. Univariate analysis was used to identify clinical and radiomics significant features. Multivariate models by Cox-regression hazards model were built for local control and survival outcome. Models were evaluated by area under the curve (AUC) of receiver operating characteristic (ROC) curve. For the LC analysis, two models selecting two groups of uncorrelated features were analyzes while one single model was built for the OS analysis.

Results

The univariate analysis lead to the identification of 15 significant radiomics features but the analysis of cross correlation showed several cross related covariates. The un-correlated variables were used to build two separate models; both resulted into a single significant radiomic covariate: model-1: energy p < 0.05, AUC of ROC 0.6659, C.I.: 0.5585–0.7732; model-2: GLNUp < 0.05, AUC 0.6396, C.I.:0.5266–0.7526.

The univariate analysis for covariates significant with respect to local control resulted in 9 clinical and 13 radiomics features with multiple and complex cross-correlations. After elastic net regularization, the most significant covariates were compacity and BCLC stage, with only compacity significant to Cox model fitting (Cox model likelihood ratio test p < 0.0001, compacity p < 0.00001; AUC of the model is 0.8014 (C.I. = 0.7232–0.8797)).

Conclusion

A robust radiomic signature, made by one single feature was finally identified. A validation phases, based on independent set of patients is scheduled to be performed to confirm the results.

Application of radiotherapy for hepatocellular carcinoma in current clinical practice guidelines

In oncologic practice, treatment guidelines provide appropriate treatment strategies based on evidence. Currently, many guidelines are used, including those of the European Association for the Study of the Liver and European Organization for Research and Treatment of Cancer (EASL-EORTC), National Comprehensive Cancer Network (NCCN), Asia-Pacific Primary Liver Cancer Expert (APPLE), and Korean Liver Cancer Study Group and National Cancer Centre (KLCSG-NCC). Although radiotherapy is commonly used in clinical practice, some guidelines do not accept it as a standard treatment modality. In this review, we will investigate the clinical practice guidelines currently used, and discuss the application of radiotherapy.

Technical advances in external radiotherapy for hepatocellular carcinoma

Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma (HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy (IMRT), stereotactic ablative body radiotherapy (SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.

Consensus for Radiotherapy in Hepatocellular Carcinoma from The 5th Asia-Pacific Primary Liver Cancer Expert Meeting (APPLE 2014): Current Practice and Future Clinical Trials

A consensus meeting to develop practice guidelines and to recommend future clinical trials for radiation therapy (RT), including external beam RT (EBRT), and selective internal RT (SIRT) in hepatocellular carcinoma (HCC) was held at the 5th annual meeting of the Asia-Pacific Primary Liver Cancer Expert consortium. Although there is no randomized phase III trial evidence, the efficacy and safety of RT in HCC has been shown by prospective and retrospective studies using modern RT techniques. Based on these results, the committee came to a consensus on the utility and efficacy of RT in the management of HCC according to each disease stage as follows: in early and intermediate stage HCC, if standard treatment is not compatible, RT, including EBRT and SIRT can be considered. In locally advanced stage HCC, combined EBRT with transarterial chemoembolization or hepatic arterial infusion chemotherapy, and SIRT can be considered. In terminal stage HCC, EBRT can be considered for palliation of symptoms and reduction of morbidity caused by the primary tumor or its metastases. Despite the currently reported benefits of RT in HCC, the committee agreed that there is a compelling need for large prospective studies, including randomized phase III trial evidence evaluating the role of RT. Specifically studies evaluating the efficacy and safety of sequential combination of EBRT and SIRT are strongly recommended.

Efficacy and Safety of Intensity-Modulated Radiotherapy Following Transarterial Chemoembolization in Patients With Unresectable Hepatocellular Carcinoma

Three-dimensional conformal radiotherapy in combination with transarterial chemoembolization (TACE) has been beneficial in patients with unresectable hepatocellular carcinoma (HCC). There have been few clinical reports on the use of intensity-modulated radiotherapy (IMRT) in combination with TACE for these patients. The purpose of this study was to assess the efficacy and toxicity of IMRT following TACE in unresectable HCC.The medical records of consecutive patients with unresectable HCC, who underwent IMRT following TACE from January 2009 to June 2014, were retrospectively reviewed in order to assess the overall survival (OS), progression-free survival (PFS), tumor response, and treatment-associated toxicity.A total of 64 lesions in 54 patients were included in the analysis. IMRT was delivered at a median dose of 50 Gy (range 44-70 Gy) at 1.8 to 2.0 Gy per fraction. The overall response rate was achieved in 64.8% of patients with complete response in 20.4% of patients at 3 months after completion of IMRT. The median OS was 20.2 months (95% CI = 8.6-31.9), and the actuarial 1-, 2-, and 3-year OS rates were 84.6%, 49.7%, and 36.7%, respectively. The median PFS was 10.5 months (95% CI = 7.3-13.7) and the 1-, 2-, and 3-year PFS rates were 44.2%, 23.4%, and 14.6%, respectively. The responders had a significantly higher OS rate than the nonresponders (3-year OS 48.0% vs 14.4%, P = 0.001). During and the first month following IMRT, 10 (18.5%) patients developed grade 3 hematological toxicity, and 3 (5.6%) developed grade 3 hepatic toxicity. No patient experienced grade 4 or 5 toxicity. Radiation-induced liver disease was not observed.Our findings suggest that IMRT following TACE could be a favorable treatment option for both its safety profile and clinical benefit in patients with unresectable HCC.

Optimal Selection of Radiotherapy as Part of a Multimodal Approach for Hepatocellular Carcinoma

A multimodal approach to treatment is a basic oncologic principle with proven survival benefits for most cancer types. However, existing guidelines recommend single modalities for treating each stage of hepatocellular carcinoma (HCC). Nonetheless, multimodal approaches can be considered for HCC, depending on the characteristics of the disease in individual cases. Radiotherapy (RT), an effective local modality, is a critical element of most multimodal approaches. Improved RTtechnology and increased understanding of the tolerance of the liver to radiation have contributed to the popularity of RT for treating liver tumors in clinical practice. Consequently, numerous reports have described the effects of RT on liver cancer, despite a lack of stringent evidence for its benefits. RT can be delivered using various technologies and approaches, which may be the source of some confusion. For example, high-dose ablative RT can be curative on its own, or high-dose ablative or conventional RT can complement other treatments such as radiofrequency ablation and transarterial chemoembolization. Combinations of systemic agents and RT can also be applied. This review discusses the optimal selection of RT as part of a multimodal approach for HCC.

Improved oncologic outcomes with image-guided intensity-modulated radiation therapy using helical tomotherapy in locally advanced hepatocellular carcinoma

AIM

To investigate whether image-guided intensity-modulated radiation therapy (IG-IMRT) improves survival in hepatocellular carcinoma (HCC) relative to 3-dimensional conformal radiotherapy (3D-CRT).

METHODS

Between 2006 and 2011, 187 HCC patients treated with definitive RT were reviewed. Median age was 53(range 51-83). All patients were stage III or IV-A. Concurrent chemoradiation was received by 178 patients (95.2 %). Overall actuarial survival (OS), progression-free survival (PFS), and infield-failure-free survival (IFFS) analyses were performed by Kaplan-Meier method. A Cox proportional hazards model was used for univariate and multivariate analysis. Pearson's chi-square test or Fisher's exact test was used to compare patient characteristics and treatment-related toxicity between the groups.

RESULTS

Sixty-five patients were treated with IG-IMRT and 122 patients with 3D-CRT. No significant differences were seen between the groups for all patient characteristics. IG-IMRT delivered higher doses than 3D-CRT (median biological effective dose 62.5 vs 53.1 Gy, P < 0.001). IG-IMRT showed significantly higher 3-year OS (33.4 vs 13.5 %, P < 0.001), PFS (11.1 vs 6.0 %, P = 0.004), and IFFS (46.8 vs 28.2 %, P = 0.007) than 3D-CRT. On univariate and multivariate analysis, RT modality was significant prognostic factor for OS (HR 2.18; 95 % CI 1.45-3.25; P < 0.001), PFS (HR 1.64; 95 % CI 1.17-2.29; P = 0.004). There was no significant difference between the two modalities for radiation-induced liver disease (P = 0.716).

CONCLUSION

Our findings suggest that IG-IMRT could be an effective treatment that provides survival benefit without increasing severe toxicity in locally advanced HCC.

Assessing the role of volumetric-modulated arc therapy in hepatocellular carcinoma

The role of volumetric-modulated arc therapy (VMAT) in hepatocellular carcinoma (HCC) remains controversial. The purpose of this study was to determine the potential clinical role of VMAT compared with three-dimensional conformal radiotherapy (3D CRT) for liver irradiation. Four-dimensional CT scans of 24patients with unresectable HCC were included and divided into two groups: (1) adjacent group (n = 11), with planning target volumes overlapping or within 1 cm adjacent to the alimentary tract; (2) nonadjacent group (n = 13), in which the normal liver itself was the dose-limiting structure. Target coverage, organs-at-risk (OARs) doses, delivery parameters, and treatment accuracy were evaluated. Superior target coverage, conformity, and homogeneity were achieved with VMAT compared with 3D CRT. In the adjacent group, VMAT provided superior sparing of serial functioning OARs including the stomach, small intestine, and spinal cord. In the nonadjacent group, VMAT provided inferior sparing of most OARs including the liver, stomach, and small intestine. For the whole group, the effective treatment time was 2.1 ± 0.3 min for 3D CRT and 3.1 ± 0.2 min for VMAT. For liver lesions adjacent to the alimentary tract, this study indicates that VMAT should be selected due to the plan quality, delivery efficiency, and superior sparing of stomach and small intestine. However, for liver lesions away from the alimentary tract, VMAT is not superior to 3D CRT for normal tissue protection.

Treatment outcomes of helical intensity-modulated radiotherapy for unresectable hepatocellular carcinoma

Background/Aims

This study reports treatment outcomes after helical intensity-modulated radiotherapy (IMRT) in unresectable hepatocellular carcinoma (HCC) patients for whom transarterial chemoembolization (TACE) was considered ineffective or unsuitable.

Methods

From January 2008 to December 2011, 22 unresectable HCC patients received helical IMRT. A daily dose of 1.8 to 4 Gy was delivered at five fractions per week to deliver a total dose of 30 to 60 Gy. The most-prescribed dose fractionation was a total dose of 50 to 57.5 Gy, with a daily dose of 2.3 to 2.5 Gy.

Results

In the entire group, the objective response rate of the primary tumor was 72.7%. In the eight patients with portal vein thrombosis (PVT), the objective response rate of PVT was 50.0%. Median disease progression-free survival was 11.8 months, and the 1-year disease progression-free survival rate was 40.2%. The median overall survival was 14.4 months, and the 1- and 2-year overall survival rates were 86.4% and 69.1%, respectively. PVT and Child-Pugh classifications were significant prognostic factors for overall survival in multivariate analyses.

Conclusions

Helical IMRT in patients with unresectable HCC resulted in high treatment response and survival rates. This study suggests helical IMRT is a practical treatment option for HCC patients in whom TACE is unsuitable or ineffective.

Radiotherapy with volumetric modulated arc therapy for hepatocellular carcinoma patients ineligible for surgery or ablative treatments

PURPOSE

The aim of this article is to report the dosimetric and clinical findings in the treatment of primary hepatocellular carcinoma (HCC) with volumetric modulated arc therapy (VMAT, RapidArc).

METHODS AND MATERIALS

A total of 138 patients were investigated. Dose prescription ranged from 45-66 Gy. Most patients (88.4 %) presented AJCC stage III or IV and 83 % were N0-M0. All were classified as Barcelona Clinic Liver Cancer (BCLC) stage A-C. All patients were treated using 10 MV photons with single or multiple, coplanar or non-coplanar arcs, and cone-down technique in case of early response of tumors.

RESULTS

The patients' median age was 66 years (range 27-87 years), 83 % were treated with 60 Gy (12 % at 45 Gy, 6 % at 66 Gy), 62 % with cone-down, 98 % with multiple arcs. The mean initial planning target volume (PTV) was 777 ± 632 cm(3); the mean final PTV (after the cone-down) was 583 ± 548 cm(3). High target coverage was achieved. The final PTV was V98% > 98 %. Kidneys received on average 5 and 8 Gy (left and right), while the maximum dose to the spinal cord was 22 Gy; mean doses to esophagus and stomach were 23 Gy and 15 Gy, respectively. The average volume of healthy liver receiving more than 30 Gy was 294 ± 145 cm(3). Overall survival at 12 months was 45 %; median survival was 10.3 months (95 % confidence interval 7.2-13.3 months). Actuarial local control at 6 months was 95 % and 93.7 % at 12 months. The median follow-up was 9 months and a maximum of 28 months.

CONCLUSION

This study showed from the dosimetric point of view the feasibility and technical appropriateness of RapidArc for the treatment of HCC. Clinical results were positive and might suggest, with appropriate care, to consider RapidArc as an additional therapeutic opportunity for these patients.

Hypofractionated radiotheapy using helical tomotherapy for advanced hepatocellular carcinoma with portal vein tumor thrombosis

Background

We want to evaluate the efficacy of helical tomotherapy (HT) for treating advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT).

Methods

We treated 35 patients for unresectable HCC combined with PVTT in whom other treatment modalities were not indicated. The tumor thrombi involved the main trunk of the portal vein in 18 patients (51.4%) and the first or second order branches in 17 patients (48.6%). A median dose of 50 Gy (range: 45–60 Gy) was delivered in 10 fractions. Capecitabine was given concomitantly at a dose of 600 mg/m² twice daily during radiotherapy.

Results

The responses were evaluated via computed tomography. There was a complete response (CR) in 5 patients (14.3%), partial response (PR) in 10 patients (28.6%), stable disease (SD) in 18 patients (51.4%) and progressive disease (PD) in 2 patients (5.7%). The Child-Pugh classification (A vs B) and the Japan integrated staging (JIS) score (2 vs 3) were statistically significant parameters that predicted the response of PVTT (p = 0.010 and p = 0.026, respectively). The median survival, one and two year survival rate of all patients was 12.9 months, 51.4% and 22.2%, respectively. The patients with tumor thrombi in the main portal trunk showed statistically inferior overall survival than patients with tumor thrombi in the portal vein branches (9.8 versus 16.6 months, respectively, p = 0.036). The responders’ median survival was 13.9 months, double 6.9 months as the median survival of the non-responders. No radiation induced liver disease or treatment related mortality was not appeared.

Conclusions

Hypofractionated radiotherapy with HT was effective not only for tumor response but also for survival in the advanced HCC patients with PVTT. And stricter patient selection by Child-Pugh classification and JIS score may maximize the potential benefits of this treatment.

Radiation treatment with volumetric modulated arc therapy of hepatocellular carcinoma patients. Early clinical outcome and toxicity profile from a retrospective analysis of 138 patients

Background

To report early outcome and toxicity for inoperable patients with hepatocellular carcinoma (HCC) treated with volumetric modulated arc therapy (VMAT).

Methods

One hundred and thirty eight patients were retrospectively analysed. Dose prescription ranged from 45 to 66Gy with conventional fractionation regime. Based on AJCC staging, 88.4% presented stage III or IV. Two-thirds (69.6%) were Child-Pugh stage A, the remaining were stage B. According to Barcelona Clinic Liver Cancer staging, 72.5% of patients were classified as stage C.

Results

Median age was 66 years, median tumor volume was 516cm³ (28 to 3620cm³). The most patients (83%) were treated with 60Gy. Median follow-up time was 9 months. One-year overall survival rate was 45% (100% for AJCC stage I, 83% for stage II, 45% for stage III and 28% for stage IV), median survival was 10.3 months (95% C.I. 7.2-13.3). Local control was achieved in 94% (of 109 assessable patients), stable disease in 29%, partial response in 53%, complete response in 11%, and progression in 6%. Radiation-induced liver disease was observed in 34 patients (25%). Gastrointestinal grade 3 toxicity was modest with a total of 17 (12.3%) cases for all endpoints.

Conclusions

Clinical results could suggest to introduce VMAT as an appropriate technique for the patients with HCC.

RapidArc vs intensity-modulated radiation therapy for hepatocellular carcinoma: a comparative planning study

OBJECTIVE

The purpose of this study is to compare the dose-volumetric results of RapidArc (RA Varian Medical Systems, Palo Alto, CA) with those of intensity-modulated radiation therapy (IMRT) for hepatocellular carcinoma.

METHODS

20 patients previously treated for hepatocellular carcinoma were the subjects of this planning study. 10 patients were treated for portal vein tumour thrombosis (Group A), and 10 patients for primary liver tumour (Group B). Prescription dose to the planning target volume was 54 Gy in 30 fractions, and the planning goal was to deliver more than 95% of prescribed dose to at least 95% of planning target volume.

RESULTS

In Group A, mean doses to liver were increased with RA vs IMRT (22.9 Gy vs 22.2 Gy, p=0.0275). However, V(30 Gy) of liver was lower in RA vs IMRT (31.1% vs 32.1%, p=0.0283). In Group B, in contrast, neither mean doses nor V(30 Gy) of liver significantly differed between the two plans. V(35 Gy) of duodenum and V(20 Gy) of kidney were decreased with RA in Groups A and B, respectively (p=0.0058 and 0.0124, respectively). Both maximal doses to spinal cord and monitor unit were significantly lower in the RA plan, regardless of the group.

CONCLUSION

The dose-volumetric results of RA vs IMRT were different according to the different target location within the liver. In general, RA tended to be more effective in the sparing of non-liver organs at risk such as duodenum, kidney, and/or spinal cord. Moreover, RA was more efficient in the treatment delivery than IMRT in terms of total monitor unit used.

The optimal selection of radiotherapy treatment for hepatocellular carcinoma

The majority of patients who present with hepatocellular carcinoma (HCC) are already at an advanced stage, and the tumors are unresectable. Radiotherapy (RT) technology can safely provide focused high-dose irradiation to these patients. A wide spectrum of RT technologiesis currently available, including internal RT consisting of Yttrium-90 ((90)Y), Iodine-131 ((131)I) anti-ferritin antibody and Homium-199 ((199)Ho) and external RT, such as three-dimensional conformal RT, intensity-modulated RT, helical tomotherapy, stereotactic body RT, and image-guided RT. However, it may be difficult for physicians to understand all of the available options and to select the optimal RT treatment. Physicians frequently query radiation oncologists on the practical indications of RT for managing patients with HCC. According to the Korean Liver Cancer Study Group practice guidelines, RT is considered appropriate for unresectable, locally advanced HCC without extrahepatic metastasis, a Child-Pugh class A or B, and tumors that occupy less than two-thirds of the liver with level II evidence. In this review, we discuss the application of various RT modalities based on disease status and the detailed indications for RT according to the Barcelona Clinic Liver Cancer staging system.

[Stereotactic body radiation therapy for liver primary and metastases: the Lille experience]

PURPOSE

The CyberKnife(®) system is a recent radiation therapy technique that allows treatment of liver lesions with real-time tracking. Because of its high precision, the dose administered to the tumor can be increased. We report Oscar-Lambret Cancer Centre experience in the treatment of primary and secondary liver lesions.

PATIENTS AND METHODS

It is a retrospective study analyzing all the patients who have been treated for their liver lesions since July 2007. A hundred and twenty patients have been treated: 42 for hepatocellular carcinoma, 72 for liver metastases and six for cholangiocarcinoma. Gold seeds need to be implanted before the treatment and are used as markers to follow the movement of the lesion due to respiration. On average, the treatment is administered in three to four sessions over 12 days. A total dose of 40 to 45 Gy at the 80% isodose is delivered. Local control and overall survival analysis with Log-rank is performed for each type of lesion.

RESULTS

Treatment tolerance is good. The most common toxicities are of digestive type, pain and asthenia. Six gastro-duodenal ulcers and two radiation-induced liver disease (RILD) were observed. At a median follow-up of 15 months, the local control rate is respectively of 80.4% and 72.5% at 1 and 2 years. Overall survival is 84.6 and 58.3% at 1 and 2 years. The local control is significantly better for the hepatocellular carcinoma and overall survival is significantly better for liver metastases (P<0.05). The local control rate and overall survival at 1 year for cholangiocarcinoma is 100%.

CONCLUSION

CyberKnife(®) is a promising technique, well tolerated, with tumoral local control rates comparable to other techniques. Its advantage is that it is very minimally invasive delivered as an outpatient procedure in a frail population of patient (disease, age).

Radiotherapeutic strategies in the management of hepatocellular carcinoma

Although potentially curative therapies for hepatocellular carcinoma (HCC) are well established, they are offered only to a limited number of patients. For advanced HCC, sorafenib is now the treatment of choice. Radiotherapy technology has evolved remarkably during the past decade and can be precisely delivered, thereby permitting higher doses to the tumor and reduced doses to surrounding normal tissues. According to the Korean Liver Cancer Study Group (KLCSG) practice guidelines, radiation therapy is considered appropriate for unresectable, locally advanced HCC without extrahepatic metastasis, Child-Pugh class A or B, and tumors occupying less than two thirds of the liver with level II evidence. In this review, we discuss the radiotherapeutic strategies for each clinical setting in patients with HCC.

High-Dose Radiotherapy with Intensity-Modulated Radiation Therapy for Advanced Hepatocellular Carcinoma

Aims and Background

We report the results of intensity-modulated radiotherapy for patients with advanced hepatocellular carcinoma who were not candidate for local ablative therapies, transarterial chemoembolization or hepatic arterial infusion chemotherapy.

Methods and Study Design

Between 2003 and 2008, 27 patients were treated with high-dose radiotherapy (median dose, 50.4 Gy). The equivalent sphere size of tumors was 11.4 ± 2.6 cm. Nineteen and 8 patients were Child-Pugh class A and B, respectively. Eighteen patients had thromboses in large veins. Six patients were treated with radiotherapy as the initial treatment modality, and 21 patients received other treatments before radiotherapy.

Results

The overall response rate was 44.4% (1 pathologic complete response and 11 partial responses). The primary failure pattern was intrahepatic disease progression. Until the last follow-up, the primary liver masses and vein thromboses did not progress in 63.6% and 60.0% of the patients, respectively. The median progression-free survival and overall survival after radiotherapy rate were 3 and 5 months, respectively. Based on univariate analyses, response, Child-Pugh classification, and vein thrombosis were significant factors for overall survival, and tumor response, tumor size, vein thrombosis, and multiplicity were significant factors for progression-free survival. Tumor response was the only significant prognostic factor for overall survival and progression-free survival based on multivariate analyses.

Conclusions

Radiotherapy with intensity-modulated radiotherapy achieved a good response rate in patients with advanced hepatocellular carcinoma, and patients who had a good response lived longer than patients who did not have a good response.

The effectiveness of particle radiotherapy for hepatocellular carcinoma associated with inferior vena cava tumor thrombus

BACKGROUND

The prognosis of patients who have hepatocellular carcinoma (HCC) associated with inferior vena cava tumor thrombus (IVCTT) is very poor, and effective treatment modalities are extremely limited. The objective of this study was to determine the therapeutic efficacy of particle radiotherapy for HCC with IVCTT.

METHODS

Between June 2001 and January 2009, 16 evaluable patients who had HCC with IVCTT were treated with particle radiotherapy. They were divided into 2 groups: 6 were treated with curative intent; 10 with palliative intent. The local tumor control rates, overall survival rates, and toxicities were evaluated.

RESULTS

All tumors treated with particle radiotherapy remained controlled without local recurrence at the last follow-up. The overall survival rates for the 16 patients at 1 and 3 years were 61.1 and 36.7%, respectively. We observed a significant difference in the survival rates according to treatment policy. The median survival time was 25.4 months for patients treated with curative intent and 7.7 months for those treated with palliative intent. The one-year survival rates were 100.0 and 33.3%, respectively. No Grade 3 or higher treatment-related toxicities were observed.

CONCLUSIONS

Particle radiotherapy is thought to be potentially effective and safe for HCC with IVCTT. Considering the current lack of effective and less-invasive local therapy for HCC with IVCTT, particle radiotherapy may therefore be an attractive new therapeutic approach for this type of HCC.

Volumetric intensity-modulated Arc (RapidArc) therapy for primary hepatocellular carcinoma: comparison with intensity-modulated radiotherapy and 3-D conformal radiotherapy

Background

To compare the RapidArc plan for primary hepatocellular carcinoma (HCC) with 3-D conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) plans using dosimetric analysis.

Methods

Nine patients with unresectable HCC were enrolled in this study. Dosimetric values for RapidArc, IMRT, and 3DCRT were calculated for total doses of 45~50.4 Gy using 1.8 Gy/day. The parameters included the conformal index (CI), homogeneity index (HI), and hot spot (V_107%) 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 (OAR) and the maximal dose at 1% volume (D_1%) for the spinal cord. The percentage of the normal liver volume receiving ≥ 40, > 30, > 20, and > 10 Gy (V_{40 Gy}, V_{30 Gy}, V_{20 Gy}, and V_{10 Gy}) and the normal tissue complication probability (NTCP) were also evaluated to determine liver toxicity.

Results

All three methods achieved comparable homogeneity for the PTV. RapidArc achieved significantly better CI and V_107% values than IMRT or 3DCRT (p < 0.05). The MUs were significantly lower for RapidArc (323.8 ± 60.7) and 3DCRT (322.3 ± 28.6) than for IMRT (1165.4 ± 170.7) (p < 0.001). IMRT achieved a significantly lower D_mean of the normal liver than did 3DCRT or RapidArc (p = 0.001). 3DCRT had higher V_{40 Gy} and V_{30 Gy} values for the normal liver than did RapidArc or IMRT. Although the V_{10 Gy} to the normal liver was higher with RapidArc (75.8 ± 13.1%) than with 3DCRT or IMRT (60.5 ± 10.2% and 57.2 ± 10.0%, respectively; p < 0.01), the NTCP did not differ significantly between RapidArc (4.38 ± 2.69) and IMRT (3.98 ± 3.00) and both were better than 3DCRT (7.57 ± 4.36) (p = 0.02).

Conclusions

RapidArc provided favorable tumor coverage compared with IMRT or 3DCRT, but RapidArc is not superior to IMRT in terms of liver protection. Further studies are needed to establish treatment outcome differences between the three approaches.

Clinical results and risk factors of proton and carbon ion therapy for hepatocellular carcinoma

BACKGROUND

The objective of this study was to evaluate the clinical outcome of proton and carbon ion therapy for hepatocellular carcinoma (HCC).

METHODS

In total, 343 consecutive patients with 386 tumors, including 242 patients (with 278 tumors) who received proton therapy and 101 patients (with 108 tumors) who received carbon ion therapy, were treated on 8 different protocols of proton therapy (52.8-84.0 gray equivalents [GyE] in 4-38 fractions) and on 4 different protocols of carbon ion therapy (52.8-76.0 GyE in 4-20 fractions).

RESULTS

The 5-year local control and overall survival rates for all patients were 90.8% and 38.2%, respectively. Regarding proton and carbon ion therapy, the 5-year local control rates were 90.2% and 93%, respectively, and the 5-year overall survival rates were 38% and 36.3%, respectively. These rates did not differ significantly between the 2 therapies. Univariate analysis identified tumor size as an independent risk factor for local recurrence in proton therapy, carbon ion therapy, and in all patients. Multivariate analysis identified tumor size as the only independent risk factor for local recurrence in proton therapy and in all patients. Child-Pugh classification was the only independent risk factor for overall survival in proton therapy, in carbon ion therapy, and in all patients according to both univariate and multivariate analyses. No patients died of treatment-related toxicities.

CONCLUSIONS

Proton and carbon ion therapies for HCC were comparable in terms of local control and overall survival rates. These therapies may represent innovative alternatives to conventional local therapies for HCC.

Dosimetric comparison of RapidArc with fixed gantry intensity-modulated radiotherapy treatment for multiple liver metastases radiotherapy

We wanted to compare the dosimetric difference and treatment efficiency of RapidArc and fixed gantry intensity-modulated radiotherapy treatment (IMRT) for multiple liver metastases. Computed tomography datasets of 10 patients were studied retrospectively. IMRT plans were generated using 5 fields and RapidArc using either 1 or 2 arcs. The dose distribution of planning target volume (PTV), organs at risk (OARs), and the normal tissue were compared. Monitor units and treatment time were scored to measure expected treatment efficiency. Both RapidArc and IMRT plans resulted in equivalent target coverage. There was no statistically significant difference for the maximum and the minimum dose of PTV. RapidArc plans achieved an improved conformity index compared with IMRT (RA1 = 1.68 ± 0.27, RA2 = 1.61 ± 0.25, IMRT = 1.80 ± 0.37). For OARs, all techniques respected planning objectives. RapidArc plans had a lower dose in V(40) of small bowel than IMRT, but were higher in mean dose of kidneys. Concerning the V(5), V(10), and V(15) of healthy tissue, RapidArc plans were higher than IMRT. However, the V(20), V(25), and V(30) of healthy tissue in RapidArc plans were lower than IMRT. Monitor units per fraction of RapidArc plans were about 40% or 46% of IMRT. Compared with IMRT plans, treatment time of RapidArc plans were reduced by 60% or 70%. All techniques respected planning objectives. RapidArc showed statistical improvements in conformity index and healthy tissue sparing with uncompromised target coverage. This, in combination with fewer monitor units and short delivery time, can lead to clinically significant advances for the treatment of multiple liver metastases.

Risk factors for survival and local recurrence after particle radiotherapy for single small hepatocellular carcinoma

BACKGROUND

Particle radiotherapy is a novel treatment for malignant tumours. The present study aimed to evaluate risk factors for overall survival and local control after particle radiotherapy of single small hepatocellular carcinoma (HCC), and to identify suitable candidates for this treatment.

METHODS

All patients with a single HCC smaller than 5 cm in diameter treated by particle radiotherapy between 2001 and 2008 were identified retrospectively from a prospectively collected database. Clinical outcomes and prognostic factors were analysed.

RESULTS

A total of 150 patients were included. Five-year overall survival and local control rates were 50.9 and 92.3 per cent respectively. Multivariable analysis revealed that several factors, including age and Child-Pugh classification, significantly influenced overall survival. Proximity to the digestive tract and Child-Pugh classification were independent risk factors for local recurrence. Other tumour factors including size, gross classification, previous treatment, macroscopic vascular invasion, and tumour location in relation to the diaphragm and large vessels did not influence local control rate.

CONCLUSION

Particle radiotherapy seems safe and effective, and may be a novel treatment for small HCC. Recurrences are more frequent when the tumour is located close to the gut.

Comparison of simple and complex liver intensity modulated radiotherapy

BACKGROUND

Intensity-modulated radiotherapy (IMRT) may allow improvement in plan quality for treatment of liver cancer, however increasing radiation modulation complexity can lead to increased uncertainties and requirements for quality assurance. This study assesses whether target coverage and normal tissue avoidance can be maintained in liver cancer intensity-modulated radiotherapy (IMRT) plans by systematically reducing the complexity of the delivered fluence.

METHODS

An optimal baseline six fraction individualized IMRT plan for 27 patients with 45 liver cancers was developed which provided a median minimum dose to 0.5 cc of the planning target volume (PTV) of 38.3 Gy (range, 25.9-59.5 Gy), in 6 fractions, while maintaining liver toxicity risk <5% and maximum luminal gastrointestinal structure doses of 30 Gy. The number of segments was systematically reduced until normal tissue constraints were exceeded while maintaining equivalent dose coverage to 95% of PTV (PTVD95). Radiotherapy doses were compared between the plans.

RESULTS

Reduction in the number of segments was achieved for all 27 plans from a median of 48 segments (range 34-52) to 19 segments (range 6-30), without exceeding normal tissue dose objectives and maintaining equivalent PTVD95 and similar PTV Equivalent Uniform Dose (EUD(-20)) IMRT plans with fewer segments had significantly less monitor units (mean, 1892 reduced to 1695, p = 0.012), but also reduced dose conformity (mean, RTOG Conformity Index 1.42 increased to 1.53 p = 0.001).

CONCLUSIONS

Tumour coverage and normal tissue objectives were maintained with simplified liver IMRT, at the expense of reduced conformity.

Helical tomotherapy for single and multiple liver tumours

Purpose

Dosimetric evaluations of single and multiple liver tumours performed using intensity-modulated helical tomotherapy (HT) were quantitatively investigated. Step-and-shoot intensity-modulated radiotherapy (SaS-IMRT) was used as a benchmark.

Methods

Sixteen patients separated into two groups with primary hepatocellular carcinomas or metastatic liver tumours previously treated using SaS-IMRT were examined and re-planned by HT. The dosimetric indices used included the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV), max/mean dose, quality index (QI), normal tissue complication probability (NTCP), V_{30 Gy}, and V_50% for the specified organs at risk (OARs). The monitor units per fraction (MU/fr) and delivery time were also analysed.

Results

For the single tumour group, both planning systems satisfied the required PTV prescription, but no statistical significance was shown by the indexes checking. A shorter delivery time and lower MU/fr value were achieved by the SaS-IMRT. For the group of multiple tumours, the average improvement in CI and HI was 14% and 4% for HT versus SaS-IMRT, respectively. Lower V_50%, V_{30 Gy} and QI values were found, indicating a significant dosimetric gain in HT. The NTCP value of the normal liver was 20.27 ± 13.29% for SaS-IMRT and 2.38 ± 2.25% for HT, indicating fewer tissue complications following HT. The latter also required a shorter delivery time.

Conclusions

Our study suggests dosimetric benefits of HT over SaS-IMRT plans in the case of multiple liver tumours, especially with regards sparing of OARs. No significant dosimetric difference was revealed in the case of single liver tumour, but SaS-IMRT showed better efficiency in terms of MU/fr and delivery time.

Comparison of coplanar and noncoplanar intensity-modulated radiation therapy and helical tomotherapy for hepatocellular carcinoma

Background

To compare the differences in dose-volume data among coplanar intensity modulated radiotherapy (IMRT), noncoplanar IMRT, and helical tomotherapy (HT) among patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT).

Methods

Nine patients with unresectable HCC and PVT underwent step and shoot coplanar IMRT with intent to deliver 46 - 54 Gy to the tumor and portal vein. The volume of liver received 30Gy was set to keep less than 30% of whole normal liver (V30 < 30%). The mean dose to at least one side of kidney was kept below 23 Gy, and 50 Gy as for stomach. The maximum dose was kept below 47 Gy for spinal cord. Several parameters including mean hepatic dose, percent volume of normal liver with radiation dose at X Gy (Vx), uniformity index, conformal index, and doses to organs at risk were evaluated from the dose-volume histogram.

Results

HT provided better uniformity for the planning-target volume dose coverage than both IMRT techniques. The noncoplanar IMRT technique reduces the V10 to normal liver with a statistically significant level as compared to HT. The constraints for the liver in the V30 for coplanar IMRT vs. noncoplanar IMRT vs. HT could be reconsidered as 21% vs. 17% vs. 17%, respectively. When delivering 50 Gy and 60-66 Gy to the tumor bed, the constraints of mean dose to the normal liver could be less than 20 Gy and 25 Gy, respectively.

Conclusion

Noncoplanar IMRT and HT are potential techniques of radiation therapy for HCC patients with PVT. Constraints for the liver in IMRT and HT could be stricter than for 3DCRT.

Three-dimensional conformal radiation therapy and intensity-modulated radiation therapy combined with transcatheter arterial chemoembolization for locally advanced hepatocellular carcinoma: an irradiation dose escalation study

PURPOSE

To determine the maximum tolerated dose (MTD) of three-dimensional conformal radiation therapy (3DCRT)/intensity-modulated radiation therapy (IMRT) combined with transcatheter arterial chemoembolization for locally advanced hepatocellular carcinoma.

METHODS AND MATERIALS

Patients were assigned to two subgroups based on tumor diameter: Group 1 had tumors <10 cm; Group II had tumors ≥10 cm. Escalation was achieved by increments of 4.0 Gy for each cohort in both groups. Dose-limiting toxicity (DLT) was defined as a grade of ≥3 acute liver or gastrointestinal toxicity or any grade 5 acute toxicity in other organs at risk or radiation-induced liver disease. The dose escalation would be terminated when ≥2 of 8 patients in a cohort experienced DLT.

RESULTS

From April 2005 to May 2008, 40 patients were enrolled. In Group I, 11 patients had grade ≤2 acute treatment-related toxicities, and no patient experienced DLT; and in Group II, 10 patients had grade ≤2 acute toxicity, and 1 patient in the group receiving 52 Gy developed radiation-induced liver disease. MTD was 62 Gy for Group I and 52 Gy for Group II. In-field progression-free and local progression-free rates were 100% and 69% at 1 year, and 93% and 44% at 2 years, respectively. Distant metastasis rates were 6% at 1 year and 15% at 2 years. Overall survival rates for 1-year and 2-years were 72% and 62%, respectively.

CONCLUSIONS

The irradiation dose was safely escalated in hepatocellular carcinoma patients by using 3DCRT/IMRT with an active breathing coordinator. MTD was 62 Gy and 52 Gy for patients with tumor diameters of <10 cm and ≥10 cm, respectively.

Dosimetry of conformal dynamic arc radiotherapy and intensity modulated radiotherapy in unresectable cholangiocarcinoma

Background: Radiotherapy in cholangiocrcinoma has to overcome organ tolerance of the upper abdomen. Hi-technology radiotherapy may improve conformity and reduce dose to those organ. Objective: Quantitatively compare the dosimetry of conformal dynamic arc radiotherapy (CD-arcRT) and intensity modulated radiotherapy (IMRT) in unresectable cholangiocarcinoma. Material and methods: Eleven cases of unresectable cholangiocarcinoma were re-planned with IMRT and CDarcRT at King Chulalongkhorn Memorial Hospital between 20 September 2004 and 31 December 2005. Both the planning techniques were evaluated using the dose volume histogram of the planning target volume and organ at risk. The conformation number and dose to critical normal structures were used to determine the techniques. Results: IMRT technique was significantly conformed to the planning target volume than CD-arcRT in term of conformation number. For critical structure, IMRT significantly reduced the radiation dose to liver in terms of mean liver dose, V30Gy and V20Gy of the right kidney. Conclusion: The advantage of IMRT was more conformity and reduced dose to critical structure compared with CD-arcRT, but there was no difference between these techniques in terms of V20Gy of left kidney and maximum dose to the spinal cord.

Approach to radiation therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the 5th most common cancer and the third most common cause of cancer-related death in the world with an estimated incidence of approximately 1 million new cases annually, has becoming a major global health problem in the world. A variety of treatment modalities, including resection, liver transplantation, transarterial chemoembolization (TACE), local ablative therapy and radiation therapy (RT) have been reported. Although partial hepatectomy and liver transplantation may offer the best chance of cure, only 15% of the patients have the chance to be treated by surgery when diagnosed. The effectiveness of systemic chemotherapy for HCC has been minimal, and local ablative therapy may offer comparable survival in patients with small HCC and preserve liver function. Recently, with developments in radiotherapy techniques, radiotherapy has been shown to play potential roles in a wide spectrum of HCC and to become more important so that it is necessary to evaluate the effect of radiotherapy in treatment of HCC. This paper is aiming mainly at the current radiation therapy strategies and their current advances, the optimal radiation therapy strategies will complement the current treatments and improve the treatment efficiency.

Proton radiotherapy for liver tumors: dosimetric advantages over photon plans

The purpose of the study is to dosimetrically investigate the advantages of proton radiotherapy over photon radiotherapy for liver tumors. The proton plan and the photon plan were designed using commercial treatment planning systems. The treatment target dose conformity and heterogeneity and dose-volume analyses of normal structures were compared between proton and photon radiotherapy for 9 patients with liver tumors. Proton radiotherapy delivered a more conformal target dose with slightly less homogeneity when compared with photon radiotherapy. Protons significantly reduced the fractional volume of liver receiving dose greater or equal to 30 Gy (V(30)) and the mean liver dose. The stomach and duodenal V(45) were significantly lower with the use of proton radiotherapy. The V(40) and V(50) of the heart and the maximum spinal cord dose were also significantly lower with the use of proton radiotherapy. Protons were better able to spare one kidney completely and deliver less dose to one (generally the left) kidney than photons. The mean dose to the total body and most critical structures was significantly decreased using protons when compared to corresponding photon plans. In conclusion, our study suggests the dosimetric benefits of proton radiotherapy over photon radiotherapy. These dosimetric advantages of proton plans may permit further dose escalation with lower risk of complications.

Treatment planning study to determine potential benefit of intensity-modulated radiotherapy versus conformal radiotherapy for unresectable hepatic malignancies

PURPOSE

To compare intensity-modulated radiotherapy (IMRT) with conformal RT (CRT) for hypofractionated isotoxicity liver RT and explore dose escalation using IMRT for the same/improved nominal risk of liver toxicity in a treatment planning study.

METHODS AND MATERIALS

A total of 26 CRT plans were evaluated. Prescription doses (24-54 Gy within six fractions) were individualized on the basis of the effective liver volume irradiated maintaining < or =5% risk of radiation-induced liver disease. The dose constraints included bowel (0.5 cm(3)) and stomach (0.5 cm(3)) to < or =30 Gy, spinal cord to < or =25 Gy, and planning target volume (PTV) to < or =140% of the prescribed dose. Two groups were evaluated: (1) PTV overlapping or directly adjacent to serial functioning normal tissues (n = 14), and (2) the liver as the dose-limiting normal tissue (n = 12). IMRT plans using direct machine parameter optimization maintained the CRT plan beam arrangements, an estimated radiation-induced liver disease risk of 5%, and underwent dose escalation, if all normal tissue constraints were maintained.

RESULTS

IMRT improved PTV coverage in 19 of 26 plans (73%). Dose escalation was feasible in 9 cases by an average of 3.8 Gy (range, 0.6-13.2) in six fractions. Three of seven plans without improved PTV coverage had small gross tumor volumes (< or =105 cm(3)) already receiving 54 Gy, the maximal prescription dose allowed. In the remaining cases, the PTV range was 9.6-689 cm(3); two had overlapped organs at risk; and one had four targets. IMRT did not improve these plans owing to poor target coverage (n = 2) and nonliver (n = 2) dose limits.

CONCLUSION

Direct machine parameter optimization IMRT improved PTV coverage while maintaining normal tissue tolerances in most CRT liver plans. Dose escalation was possible in a minority of patients.

Intensity-modulated radiation therapy and helical tomotherapy: its origin, benefits, and potential applications in veterinary medicine

Intensity-modulated radiation therapy (IMRT), especially image-guided IMRT as represented by helical tomotherapy, is a novel approach to therapy and is rapidly evolving. Both of these forms of therapy aim to allow targeted radiation delivery to the tumor volume while minimizing dose to the surrounding normal tissues. Adaptive radiation therapy and conformal avoidance are possible with intensity-modulated therapy and helical tomotherapy, which offer opportunities for improved local tumor control, decreased normal tissue toxicity, and improved survival and quality of life. Human and veterinary patients are likely to benefit from the continued development of this radiation delivery technique, and data over the next several years should be crucial in determining its true benefit.

Feasibility and efficacy of high-dose three-dimensional-conformal radiotherapy in cirrhotic patients with small-size hepatocellular carcinoma non-eligible for curative therapies--mature results of the French Phase II RTF-1 trial

PURPOSE

Hepatocellular carcinoma (HCC) is a poor prognosis tumor, and only 20% of patients will benefit from curative therapies (surgery, liver transplantation, percutaneous ablation). Although conventional radiotherapy has been traditionally regarded as inefficient and toxic for cirrhotic patients, three-dimensional conformal radiotherapy (3DCRT) has provided promising preliminary data for the treatment of HCC.

METHODS AND MATERIALS

Prospective phase II trial including Child-Pugh A/B cirrhotic patients with small-size HCC (1 nodule < or =5 cm, or 2 nodules < or =3 cm) nonsuitable for curative treatments, to assess tolerance and efficacy of high-dose (66 Gy, 2 Gy/fraction) 3DCRT.

RESULTS

Twenty-seven patients were enrolled. Among the 25 assessable patients, tumor response was observed for 23 patients (92%), with complete response for 20 patients (80%), and partial response for 3 patients (12%). Stable disease was observed in 2 patients (8%). Grade 4 toxicities occurred in 2 of 11 (22%) Child-Pugh B patients only. Child-Pugh A patients tolerated treatment well, and 3/16 (19%) developed asymptomatic Grade 3 toxicities.

CONCLUSION

High-dose 3DCRT is a noninvasive, well-tolerated modality that is highly suitable for the treatment of small HCCs in cirrhotic patients, with promising results. However, additional trials are needed to optimize this technique and formally compare it with the usual curative approaches.

Intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high-grade gliomas: does IMRT increase the integral dose to normal brain?

PURPOSE

To determine whether intensity-modulated radiotherapy (IMRT) treatment increases the total integral dose of nontarget tissue relative to the conventional three-dimensional conformal radiotherapy (3D-CRT) technique for high-grade gliomas.

METHODS AND MATERIALS

Twenty patients treated with 3D-CRT for glioblastoma multiforme were selected for a comparative dosimetric evaluation with IMRT. Original target volumes, organs at risk (OAR), and dose-volume constraints were used for replanning with IMRT. Predicted isodose distributions, cumulative dose-volume histograms of target volumes and OAR, normal tissue integral dose, target coverage, dose conformity, and normal tissue sparing with 3D-CRT and IMRT planning were compared. Statistical analyses were performed to determine differences.

RESULTS

In all 20 patients, IMRT maintained equivalent target coverage, improved target conformity (conformity index [CI] 95% 1.52 vs. 1.38, p < 0.001), and enabled dose reductions of normal tissues, including brainstem (D(mean) by 19.8% and D(max) by 10.7%), optic chiasm (D(mean) by 25.3% and D(max) by 22.6%), right optic nerve (D(mean) by 37.3% and D(max) by 28.5%), and left optic nerve (D(mean) by 40.6% and D(max) by 36.7%), p < or = 0.01. This was achieved without increasing the total nontarget integral dose by greater than 0.5%. Overall, total integral dose was reduced by 7-10% with IMRT, p < 0.001, without significantly increasing the 0.5-5 Gy low-dose volume.

CONCLUSIONS

These results indicate that IMRT treatment for high-grade gliomas allows for improved target conformity, better critical tissue sparing, and importantly does so without increasing integral dose and the volume of normal tissue exposed to low doses of radiation.

Radiation therapy for hepatocellular carcinoma: from palliation to cure

Technologic advances have provided the means to deliver tumoricidal doses of radiation therapy (RT) to patients with unresectable hepatocellular carcinoma (HCC) while avoiding critical normal tissues, providing the opportunity to use RT for curative intent treatment of HCC. For the current report, the expanded role of external beam RT in the setting of HCC from palliation to cure was reviewed. A systematic literature search was undertaken using the MEDLINE data base and secondary references to identify peer-reviewed, English-language articles that reported clinical outcomes after external beam RT alone or in combination with other treatments for HCC. Abstracts from the 2005 American Society of Clinical Oncology, American Society for Therapeutic Radiology and Oncology, American Gastrointestinal Association, and Society of Surgical Oncology Gastrointestinal Cancer Symposium also were included in the search. More than 60 articles reporting on clinical outcomes among patients who received RT for HCC have been published since 1990, including 20 articles that described unique sets of at least 15 patients. RT was used for palliation, to improve local control, and with curative intent in a wide spectrum of patients who most often were unsuitable for surgery and other treatments. Pain reduction following RT was noted in approximately 75% of patients with bone metastases from HCC who received RT. For patients with liver-confined disease treated with conformal RT, proton beam RT, and/or image guided RT with or without transarterial chemoembolization (TACE), local control response rates ranged from 40% to 90%, and the median survival ranges from 10 months to 25 months. For patients with HCC who had portal vein thrombus, the median survival after RT to treat the thrombus and/or the hepatic tumor with or without TACE ranged from 5.3 months to 9.7 months. Although outcomes after high-dose conformal RT for liver-confined HCC were excellent, the potential survival benefit of RT should be tested in randomized controlled trials that require international collaboration.

Management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors globally, with varying prevalence based on endemic risk factors. In high-risk populations, including those with hepatitis B or C or with cirrhosis, serum alpha-fetoprotein (AFP) and screening ultrasound have improved detection of resectable HCC. Treatment options, including surgical resection, for patients with HCC must be selected based on the number and size of hepatic tumors, underlying hepatic function, patient condition, and available resources. An approach, which has been summarized shows the corresponding treatment choices under given clinical circumstances. For cirrhotic patients with less than three tumor nodules of a size less than 3 cm or a solitary HCC less than 5 cm, liver transplantation offers long-term survival similar to that observed in patients transplanted for nonmalignant disease. Ablative treatment using either chemical or thermal techniques provides locally effective tumor destruction. Transcatheter arterial chemoembolization (TACE) is commonly used for palliation of unresectable tumors as well as an adjunct to surgical resection, treatment of tumors before transplant, and in conjunction with other ablative therapies in a multimodality approach. Regional approaches to chemotherapy have produced more encouraging results than systemic chemotherapy, although both remain ineffective for long-term tumor control. Several newer treatment modalities are under investigation, including gene therapy, tagged antibodies, isolated perfusion, and novel radiotherapy techniques.

Tolérance et efficacité de la radiothérapie de conformation en cas de carcinome hépatocellulaire chez le patient cirrhotique. Résultats de l'essai de phase II RTF1

PURPOSE

While some patients presenting with hepatocellular carcinoma (HCC) benefit from curative therapies (transplantation, surgery, percutaneous ablation), others are only candidates for palliative options such as chemoembolization or symptomatic care. Although conventional external-beam radiotherapy of the liver is regarded as little efficient and potentially toxic in cirrhotic patients, 3-dimensional conformal radiotherapy (CRT), by decreasing the amount of normal liver included in the radiation portal, allows dose escalation to occur without increasing the risk of radiation-induced hepatitis. This trial was designed to assess the efficacy and tolerance of CRT for small-size HCC in cirrhotic patients.

PATIENTS AND METHODS

Prospective phase II trial including stage A/B cirrhotic patients with small-size HCC not suitable for curative treatments; CRT consisted in a standard fractionation radiation, with a total dose of 66 Gy.

RESULTS

Twenty-seven patients were included, 15 of whom had previously been treated for HCC; mean age was 68. Among the 23 assessable patients, 18 (78%) presented with complete response, 3 (13%) with partial response, and 2 with no response. Acute complications occurred in 24 patients, and were mainly acceptable (grade 1/2: 22 patients, grade 3/4: 11 patients, 4 (15%) of whom had clinical and/or hematological toxicities). Only 2 (9%) grade 3/4 clinical and/or hematological late toxicities are reported.

CONCLUSION

CRT is a non-invasive curative technique highly suitable for small-size HCC in cirrhotic patients; further investigations are needed to compare it to the other available treatments, and to integrate it into the curative therapeutic algorithm of HCC.