Changes in Liver Volume Observed Following Sorafenib and Liver Radiation Therapy

Liver SBRT dose accumulation to assess the impact of anatomic variations on normal tissue doses and toxicity in patients treated with concurrent sorafenib

BACKGROUND AND PURPOSE

Unexpected liver volume reductions occurred during trials of liver SBRT and concurrent sorafenib. The aims were to accumulate liver SBRT doses to assess the impact of these anatomic variations on normal tissue dose parameters and toxicity.

MATERIALS AND METHODS

Thirty-two patients with hepatocellular carcinoma (HCC) or metastases treated on trials of liver SBRT (30-57 Gy, 6 fractions) and concurrent sorafenib were analyzed. SBRT doses were accumulated using biomechanical deformable registration of daily cone-beam CT. Dose deviations (accumulated-planned) for normal tissues were compared for patients with liver volume reductions > 100 cc versus stable volumes, and accumulated doses were reported for three patients with grade 3-5 luminal gastrointestinal toxicities.

RESULTS

Patients with reduced (N = 12) liver volumes had larger mean deviations of 0.4-1.3 Gy in normal tissues, versus -0.2-0.4 Gy for stable cases (N = 20), P > 0.05. Deviations > 5% of the prescribed dose occurred in both groups. Two HCC patients with toxicities to small and large bowel had liver volume reductions and deviations to the maximum dose of 4% (accumulated 36.9 Gy) and 3% (accumulated 33.4 Gy) to these organs respectively. Another HCC patient with a toxicity of unknown location plus tumor rupture, had stable liver volumes and deviations to luminal organs of -6% to 4.5% (accumulated < 30.5 Gy).

CONCLUSION

Liver volume reductions during SBRT and concurrent sorafenib were associated with larger increases in accumulated dose to normal tissues versus stable liver volumes. These dosimetric changes may have further contributed to toxicities in HCC patients who have higher baseline risks.

Stereotactic Radiotherapy for Hepatocellular Carcinoma, Radiosensitization Strategies and Radiation-Immunotherapy Combination

Simple Summary

Radiotherapy is rapidly turning into a crucial component of multidisciplinary treatment for liver cancer because many patients are not surgical treatment candidates. Thanks to technical developments, radiotherapy have achieved high precision treatments, making it possible to eliminate tumor cells without severe damage to the liver and other organs. Stereotactic Body Radiation Therapy is an advanced radiotherapy technique able to eradicate malignant tumors wherever they are located in properly selected patients. The best use of radiotherapy, the most fruitful radiotherapy strategy, and the best way to combine it with other treatments for liver cancer are largely unknown. Radiosensitizers, agents that can potentiate radiotherapy, could broaden the radiotherapeutic landscape. Radiotherapy potentiation can be achieved with diverse treatments, not only drugs but also nanoparticles. In order to clear up the performance of radiotherapy in liver cancer management in the future and the best ways to potentiate its effects, considerable medical research is needed.

Abstract

Stereotactic body radiotherapy (SBRT) is an emerging ablative modality for hepatocellular carcinoma (HCC). Most patients with HCC have advanced disease at the time of diagnosis, and therefore, are not candidates for definitive-intent therapies such as resection or transplantation. For this reason, various alternative local and regional therapies have been used to prevent disease progression, palliate symptoms, and delay liver failure. Stereotactic body radiation therapy is a non-invasive technique of delivering ablative doses of radiation to tumors while sparing normal or non-tumor hepatic tissue. Incorporation of SBRT in multidisciplinary HCC management is gradual, initially applied when other liver-directed therapies have failed or are contraindicated, and tried in combination with other locoregional or systemic therapies for more unfavorable conditions by more experienced teams. In order to improve SBRT therapeutic ratio, there has been much interest in augmenting the effect of radiation on tumors by combining it with chemotherapy, molecularly targeted therapeutics, nanoparticles, and immunotherapy. This review aims to synthesize available evidence to evaluate the clinical feasibility and efficacy of SBRT for HCC, and to explore novel radio-potentiation concepts by combining SBRT with novel therapeutics. It is expected that those approaches would result in improved therapeutic outcomes, even though many questions remain with regard to the optimal way to assemble treatments. Further trials are needed to evaluate and consolidate these promising therapies for HCC.

Role of phosphatidylinositol 3-kinase signaling pathway in radiation-induced liver injury

Transforming growth factor-β1 (TGF-β1) is one of critical cytokines in radiation-induced liver injury. Hepatic stellate cells (HSC) are activated in the early stage of radiation-induced liver injury. However, it is currently unclear whether phosphatidylinositol 3-kinase (PI3K/Akt) signal pathway is activated in radiation-induced liver injury. Herein, male Sprague-Dawley rats were irradiated with 6 MV X-rays (30 Gy) on the right liver. Next, Hematoxylin and eosin staining, Masson staining, and electron microscopy were performed to examine pathological changes. Immunohistochemistry was performed to assess the expression of TGF-β1, α-SMA, and p-Akt (S473) in liver tissues. In vitro, rat HSC cell line HSC-T6 cells were given different doses of 6 MV X-ray irradiation (10 and 20 Gy) and treated with LY294002. The expression of α-SMA and p-Akt in mRNA and protein levels were measured by reverse transcription-polymerase chain reactioin (RT-PCR) and Western blot. TGF-β1 expression was detected by enzyme-linked immuno sorbent assay (ELISA). After irradiation, the liver tissues showed obvious pathological changes, indicating the establishment of the radiation-induced liver injury. Expression levels of TGF-β1, α-SMA, and p-Akt (S473) protein in liver tissues were significantly increased after irradiation, and this increase was in a time-dependent manner, suggesting the activation of HSC and PI3K/Akt signal pathway. in vitro experiments showed that the TGF-β1 secreted by HSCs, and the expression of Akt and α-SMA at mRNA and protein levels were significantly increased in irradiation groups. However, the expression of TGF-β1, Akt, and α-SMA were significantly decreased in PI3K/Akt signal pathway inhibitor LY294002-treated group. Our results suggest that during radiation-induced liver injury, HSCs are activated by TGF-β1-mediated PI3K/Akt signal pathway.

Radiosensitization of Hepatocellular Carcinoma through Targeting Radio-Associated MicroRNA

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. For patients who are resistant to monotherapy, multimodal therapy is a basic oncologic principle that incorporates surgery, radiotherapy (RT), and chemotherapy providing survival benefits for patients with most types of cancer. Although liver has low tolerance for radiation, high-precision RT for local HCC minimizes the likelihood of radiation-induced liver disease (RILD) in noncancerous liver tissue. RT have several therapeutic benefits, including the down-staging of tumors to make them resectable and repression of metastasis. The DNA damage response (DDR) is a cellular response to irradiation (IR), including DNA repair of injured cells and induction of programmed cell death, thereby resulting in maintenance of cell homeostasis. Molecules that block the activity of proteins in DDR pathways have been found to enhance radiotherapeutic effects. These molecules include antibodies, kinase inhibitors, siRNAs and miRNAs. MicroRNAs (miRNAs) are short non-coding regulatory RNAs binding to the 3'-untranslated regions (3'-UTR) of the messenger RNAs (mRNAs) of target genes, regulating their translation and expression of proteins. Thus, miRNAs and their target genes constitute complicated interactive networks, which interact with other molecules during carcinogenesis. Due to their promising roles in carcinogenesis, miRNAs were shown to be the potential factors that mediated radiosensitivity and optimized outcomes of the combination of systemic therapy and radiotherapy.

Evolving Systemic Therapy in Hepatocellular Carcinoma: Current Management and Opportunities for Integration With Radiotherapy

The majority of patients with hepatocellular carcinoma (HCC) present with advanced disease. While first-line therapy with sorafenib is considered standard of care for patients with advancedHCC, outcomes remain poor. Despite early evidence of antitumor activity from Phase II trials of multiple other tyrosine kinase inhibitors, Phase III trials have largely failed to show an improvement insurvival outcomes over sorafenib. Given the encouraging early results with liver-directed radiotherapy for patients with advanced HCC, there is an increased interest in combination of these therapies tooptimize patient outcomes and improve survival by maximizing both local and distant disease control. Phase II trials of checkpoint inhibitors in HCC have also reported encouraging results, and Phase IIItrials are ongoing. Trials of combining radiotherapy with immunotherapy in solid tumors have shown intriguing results, potentially reflecting the opportunity for synergistic effects with the use of both modalities.

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

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

Challenges and opportunities of using stereotactic body radiotherapy with anti-angiogenesis agents in tumor therapy

Microvessels promote proliferation of tumor cells by delivering oxygen and nutrients, but rapid growth of tumors results in unmet demands for oxygen and nutrients, thereby creating a hypoxia microenvironment. Under hypoxic conditions, vascular endothelial cells (ECs) initiate the formation of immature and abnormal microvasculature. This results in leakage and tortuosity that facilitates tumor cell invasion, metastasis and resistance to cytotoxic treatment. Radiotherapy (RT) is a vital tumor treatment modality. Currently, more than 60% of patients with malignant tumors receive RT at certain points during their treatment. Hypoxia induced by abnormal microvessels can hamper the cytotoxic effect of ionizing radiation, particularly, stereotactic body radiotherapy (SBRT). Anti-angiogenesis (AA) agents are known to reduce and renormalize microvessels in tumors, and hence alleviate hypoxia. The combination of AA agents with SBRT may have a synergistic role in inhibiting the growth of tumors. On the contrary, large doses of irradiation may affect tumor microvessels itself. In this review, we aim to clarify the relationship between SBRT and microvessel formation in tumors. In addition, we provide a retrospective analysis of the combination therapy involving SBRT and AA agents in preclinical and clinical practice to define its role in anti-tumor treatment.

Excellent local control and tolerance profile after stereotactic body radiotherapy of advanced hepatocellular carcinoma

Background

To evaluate the efficacy and toxicity of stereotactic body radiotherapy (SBRT) in the treatment of advanced hepatocellular carcinoma (HCC).

Material and Methods

Patients with large HCCs (median diameter 7 cm, IQR 5-10 cm) with a Child-Turcotte-Pugh (CTP) score A (60%) or B (40%) and Barcelona-Clinic Liver Cancer (BCLC) classification stage B or C were treated with 3 to 12 fractions to allow personalized treatment according to the size of the lesions and the proximity of the lesions to the organs at risk aiming to give high biologically equivalent doses assuming an α/β ratio of 10 Gy for HCC. Primary end points were in-field local control and toxicity assessment.

Results

Forty seven patients with 64 lesions were treated with SBRT (median 45 Gy in 3–12 fractions) with a median follow up for patients alive of 19 months. The median biological effective dose was 76 Gy (IQR 62–86 Gy). Tumor vascular thrombosis was present in 28% and an underlying liver disease in 87% (hepatitis B or C in 21%, alcohol related in 51%, nonalcoholic steatohepatitis in 13% of the patients, primary biliary cirrhosis 2%). Eighty three percent received prior and in most cases multiple therapies. Local control at 1 year was 77%. The median overall survival from the start of SBRT was 9 months (95% CI 7.7–10.3). Gastrointestinal toxicities grade ≥ 2 were observed in 3 (6.4%) patients. An increase in CTP score without disease progression was observed in 5 patients, of whom one patient developed a radiation induced liver disease. One patient died due to liver failure 4 months after treatment.

Conclusion

SBRT is an effective local ablative therapy which leads to high local control rates with moderate toxicity for selected patients with large tumors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-017-0851-7) contains supplementary material, which is available to authorized users.

The clinical application of angiostatic therapy in combination with radiotherapy: past, present, future

Although monotherapy with angiostatic drugs is still far from effective, there is abundant evidence that angiostatic therapy can improve the efficacy of conventional treatments like radiotherapy. This has instigated numerous efforts to optimize and clinically implement the combination of angiostatic drugs with radiation treatment. The results from past and present clinical trials that explored this combination therapy indeed show encouraging results. However, current findings also show that the combination has variable efficacy and is associated with increased toxicity. This indicates that combining radiotherapy with angiostatic drugs not only holds opportunities but also provides several challenges. In the current review, we provide an update of the most recent insights from clinical trials that evaluated the combination of angiostatic drugs with radiation treatment. In addition, we discuss the outstanding questions for future studies in order to improve the clinical benefit of combining angiostatic therapy with radiation therapy.