Clinical application of advances and innovation in radiation treatment of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) management has evolved over the past two decades, with the development of newer treatment modalities. While various options are available, unmet needs are reflected through the mixed treatment outcome for intermediate-stage HCC. As HCC is radiosensitive, radiation therapies have a significant role in management. Radiation therapies offer local control for unresectable lesions and for patients who are not surgical candidates. Radiotherapy also provides palliation in metastatic disease, and acts as a bridge to resection and transplantation in selected patients. Advancements in radiotherapy modalities offer improved dose planning and targeted delivery, allowing for better tumor response and safer dose escalations while minimizing the risks of radiation-induced liver damage. Radiotherapy modalities are broadly classified into external beam radiation therapy and selective internal radiation therapy. With emerging modalities, radiotherapy plays a complementary role in the multidisciplinary care of HCC patients.

Aim

We aim to provide an overview of the role and clinical application of radiation therapies in HCC management.

Relevance for Patients

The continuous evolution of radiotherapy techniques allows for improved therapeutic outcomes while mitigating unwanted adverse effects, making it an attractive modality in HCC management. Rigorous clinical studies, quality research and comprehensive datasets will further its application in the present era of evidence-based practice in Medicine.

Phase I Radiation Dose-Escalation Study to Investigate the Dose-Limiting Toxicity of Concurrent Intra-Arterial Chemotherapy for Unresectable Hepatocellular Carcinoma

Concurrent intra-arterial chemotherapy and radiotherapy (iA-CCRT) can increase the response rate in hepatocellular carcinoma (HCC), but may cause a higher toxicity. We conducted this Phase I study to investigate the dose-limiting toxicity of iA-CCRT for HCC. In total, 52.5 Gy in 25 fractions was prescribed as planning target volume (PTV) 1 at dose level 1. The dose escalation was 0.2 Gy per fraction and up to 2.5 Gy, with 62.5 Gy at level 3. Concurrent intra-arterial 5-fluorouracil was administered during the first and fifth weeks of radiotherapy (RT). Toxicities were graded using the Common Toxicity Criteria for Adverse Events, version 4.0. Results: Seventeen patients with HCC were analyzed: four at dose level 1, 6 at level 2, and 7 at level 3. The mean irradiated dose administered to the uninvolved liver at each dose level was 21.3, 21.6, and 18.2 Gy, respectively. There was no grade ≥3 gastrointestinal toxicity; two patients experienced grade 3 hyperbilirubinemia. All patients had Child-Pugh class A disease, but 3 patients developed class B disease after iA-CCRT. During a median follow-up of 13 months, the median progression-free survival (PFS) and overall survival (OS) were 10 and 22 months, respectively. Patients treated at dose level 3 showed improved PFS and OS. Conclusions: Radiation dose escalation of iA-CCRT did not cause any significant toxicities in patients with advanced HCC. Further large-scale studies with long-term follow-up are needed to determine the efficacy and feasibility of higher doses of iA-CCRT.

Impact of treatment planning using a structure block function on the target and organ doses related to patient movement in cervical esophageal cancer: A phantom study

Helical tomotherapy (HT) can restrict beamlets passing through the virtual contour on computed tomography (CT) image in dose optimization, reducing the dose to organs at risk (OARs). Beamlet restriction limits the incident beamlet angles; thus, the proper planning target volume (PTV) margin may differ from that of the standard treatment plan without beamlet restriction, depending on the patient's movement during dose delivery. Dose distribution changes resulting from patient movement have not been described for treatment plans with beamlet restriction. This study quantified changes in dose distribution to the target and OARs when beamlet restriction is applied to cervical esophageal cancer treatment plan using HT by systematically shifting a phantom. Treatment plans for cervical esophageal cancers with and without beamlet restriction modes [directional block (DB) and nonblock (NB), respectively] were designed for CT images of the RANDO phantom. The PTV margin for the DB mode was set to be the same as that for the NB mode (5 mm). The CT image was intentionally shifted by ±1, ±2, and ±3 voxels in the left–right, anterior–posterior, and superior–inferior directions, and the dose distribution was recalculated for each position using the fluence for the NB or DB mode. When the phantom shift was within the same PTV margin as the NB mode, changes in doses to the targets, lungs, heart, and spinal cord in the DB mode were small as those in the NB mode. In conclusion, the virtual contour shape used in this study would provide safe delivery even with patient movement within the same PTV margin as for the NB mode.

Benefit of volumetric-modulated arc therapy over three-dimensional conformal radiotherapy for stage I-II extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in the stomach: a dosimetric comparison

Purpose

To retrospectively analyze dosimetric parameters of volumetric-modulated arc therapy (VMAT) and three-dimensional conformal radiotherapy (3D-CRT) delivered to extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue in the stomach (gastric MALT lymphoma) to find out advantages of VMAT and conditions for definite benefits of VMAT.

Materials and Methods

Fifty patients with stage I-II gastric MALT lymphoma received VMAT (n = 14) or 3D-CRT (n = 36) between December 2005 and April 2018. Twenty-seven patients were categorized according to whether the planning target volume (PTV) overlaps kidney(s). Dosimetric parameters were analyzed by dose-volume histogram.

Results

Radiation dose to the liver was definitely lower with VMAT in terms of mean dose (p = 0.026) and V₁₅ (p = 0.008). The V₁₅ of the left kidney was lower with VMAT (p = 0.065). For those with PTV overlapping kidney(s), the left kidney V₁₅ was significantly lower with VMAT. Furthermore, the closer the distance between the PTV and kidneys, the less the left kidney V₁₅ with VMAT (p = 0.037). Delineation of kidney(s) by integrating all respiratory phases had no additional benefit.

conclusions

VMAT significantly increased monitor units, reduced treatment time and radiation dose to the liver and kidneys. The benefit of VMAT was definite in reducing the left kidney V₁₅, especially in geometrically challenging conditions of overlap or close separation between PTV and kidney(s).

Intensity-modulated radiotherapy for hepatocellular carcinoma: dosimetric and clinical results

Since the introduction of 3-dimensional conformal radiotherapy (3DCRT), new radiotherapy techniques have expanded the indication of radiotherapy for the treatment of hepatocellular carcinoma (HCC), from the hitherto palliative to a now curative-intent purpose. Intensity-modulated radiotherapy (IMRT), currently the most advanced radiotherapy technique, is considered an attractive option for the treatment of HCC, and is more widely applied because it can deliver a higher dose to the tumor than 3DCRT while sparing surrounding normal organs. However, the advantages and potential disadvantages of IMRT for treating HCC have not been fully established. This article deals with three different IMRT techniques, including static IMRT and volumetric modulated arc therapy using conventional multileaf collimator (MLC) mounted linear accelerators, and helical IMRT using binary MLC mounted helical tomotherapy machine. We review dosimetric and clinical studies for these IMRT techniques for the treatment of HCC.

Radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma: dosimetric comparison and risk assessment of solid secondary cancer

Purpose

To determine the optimal radiotherapy technique for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), we compared the dosimetric parameters and the risk of solid secondary cancer from scattered doses among anterior-posterior/posterior-anterior parallel-opposed fields (AP/PA), anterior, posterior, right, and left lateral fields (4_field), 3-dimensional conformal radiotherapy (3D-CRT) using noncoplanar beams, and intensity-modulated radiotherapy composed of 7 coplanar beams (IMRT_co) and 7 coplanar and noncoplanar beams (IMRT_non).

Materials and Methods

We retrospectively generated 5 planning techniques for 5 patients with gastric MALToma. Homogeneity index (HI), conformity index (CI), and mean doses of the kidney and liver were calculated from the dose-volume histograms. Applied the Biological Effects of Ionizing Radiation VII report to scattered doses, the lifetime attributable risk (LAR) was calculated to estimate the risk of solid secondary cancer.

Results

The best value of CI was obtained with IMRT, although the HI varied among patients. The mean kidney dose was the highest with AP/PA, followed by 4_field, 3D-CRT, IMRT_co, and IMRT_non. On the other hand, the mean liver dose was the highest with 4_field and the lowest with AP/PA. Compared with 4_field, the LAR for 3D-CRT decreased except the lungs, and the LAR for IMRT_co and IMRT_non increased except the lungs. However, the absolute differences were much lower than <1%.

Conclusion

Tailored RT techniques seem to be beneficial because it could achieve adjacent organ sparing with very small and clinically irrelevant increase of secondary solid cancer risk compared to the conventional techniques.

Exploration of Superior Modality: Safety and Efficacy of Hypofractioned Image-Guided Intensity Modulated Radiation Therapy in Patients with Unresectable but Confined Intrahepatic Hepatocellular Carcinoma

PURPOSE

To evaluate the efficacy and safety of hypofractioned image-guided intensity modulated radiation therapy (IG-IMRT) for unresectable but confined intrahepatic hepatocellular carcinoma in comparison with conventional 3-dimensional conformal radiotherapy (3D-CRT).

METHODS

Ninety patients with unresectable but confined intrahepatic hepatocellular carcinoma without distant metastasis and tumor thrombosis received external beam radiation therapy. Of these patients, 45 received IG-IMRT and 45 received 3D-CRT. The IG-IMRT design delivered a median total hypofractionated dose of 54 Gy (2.2-5.5 Gy/fx), and 3D-CRT delivered a median total dose of 54 Gy with a conventional fraction (2.0 Gy/fx). The clinical response, overall survival, and side effects were analyzed.

RESULTS

The IG-IMRT group showed significantly higher 1-year survival (93.3 versus 77.8%) and 2-year survival (73.3 versus 51.1%) and longer median survival (44.7 versus 24.0 months) than the 3D-CRT group. Multivariate analysis indicated that the patients with intrahepatic tumors smaller than 8 cm, prior TACE before RT, and IG-IMRT would have a survival benefit. There were no significant differences in the rates of side effects between the two groups.

CONCLUSION

Hypofractioned IG-IMRT could improve the therapeutic response and confer a potential survival of patients with unresectable but confined intrahepatic hepatocellular carcinoma compared to 3D-CRT with acceptable toxicity.

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.

Loss of EGF-dependent cell proliferation ability on radioresistant cell HepG2-8960-R

Acquired radioresistance of cancer cells interferes with radiotherapy and increases the probability of cancer recurrence. HepG2-8960-R, which is one of several clinically relevant radioresistant (CRR) cell lines, has a high tolerance to the repeated clinically relevant doses of X-ray radiation. In this study, HepG2-8960-R had slightly lower cell proliferation ability than HepG2 in the presence of FBS. In particular, epidermal growth factor (EGF) hardly enhanced cell proliferation and DNA synthesis in HepG2-8960-R. Additionally, EGF could not induce the activation of Erk1/2, because the expression of EGF receptor (EGFR) protein decreased in HepG2-8960-R in accordance with the methylation of the EGFR promoter region. Therefore, cetuximab did not inhibit HepG2-8960-R cell proliferation. Our study showed that HepG2-8960-R had radioresistant and cetuximab-resistant abilities.

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.

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.

Application of Radiotherapeutic Strategies in the BCLC-Defined Stages of Hepatocellular Carcinoma

The Barcelona Clinic Liver Cancer (BCLC) staging system is the method currently used to stage hepatocellular carcinoma (HCC) and therefore plays an important role in deciding on an appropriate course of treatment. BCLC takes into consideration the extent of the disease as well as patient factors such as hepatic function and performance status. However, it does not propose solutions for all clinical situations. Although radiotherapy (RT) is not included in the BCLC guidelines, the potent local antitumor effect of RT should be considered seriously as a part of the treatment strategy. Novel RT technologies introduced during the last decade have made it possible to deliver higher doses of radiation to the tumor while avoiding damage to critical normal tissues adjacent to the tumor. Because of the growing interest in using RT for HCC patients unfit for or progressed beyond standard treatments, the role of RT for HCC patients needs to be specified within the BCLC staging system. Curative RT can be used for patients with either very early or early stage BCLC; focal high dose RTs, such as stereotactic body RT, are especially useful. Intermediate or advanced stage disease confined to the liver can be managed safely and effectively by localized RT in conjunction with other treatment modalities such as transarterial chemoembolization or concurrent or adjuvant chemotherapy. In this review, the efficacy of RT in each BCLC stage of HCC will be discussed.

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.

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.