Stereotactic body radiotherapy in the management of hepatocellular carcinoma: An Australian multi-institutional patterns of practice review

Comparison of outcomes following surgical resection, percutaneous ablation or stereotactic body radiation therapy in early-stage, solitary and small (≤3 cm) treatment-naïve hepatocellular carcinoma

INTRODUCTION

Stereotactic body radiation therapy (SBRT) is associated with high local control rates in hepatocellular carcinoma (HCC). This study reports the outcomes of SBRT compared to surgical resection (SR) and percutaneous ablation (PA) for treatment-naïve, solitary HCCs ≤3 cm.

METHODS

This was a retrospective study of patients with BCLC stage 0/A HCC with a single ≤3 cm lesion, treated with curative intent between 2016 and 2020. SBRT was used for patients considered unsuitable for SR or PA. The co-primary endpoints were progression-free survival (PFS) and overall survival (OS). The secondary endpoints were treatment-related clinical toxicity rates and local control (LC) rates.

RESULTS

There were 112 patients included in this study. SBRT was delivered in 36 patients (32.1%), 51 had PA (45.5%) and 25 underwent SR (22.3%). Median follow-up was 23 months (range, 3-60 months) from diagnosis. The 3-year PFS and OS were 67% and 69% following SBRT, 55% and 80% following PA, and 85% and 100% following SR, respectively. Patients in the SR cohort had significantly better 3-year PFS and OS compared to SBRT and PA groups (p = 0.03 and p = 0.04, respectively). There was no significant difference in PFS (p = 0.15) or OS (p = 0.23) between SBRT and PA treated patients. The 3-year LC rate for the entire cohort was 98%.

CONCLUSIONS

In patients with treatment-naïve, early-stage solitary HCCs ≤3 cm, SBRT was associated with comparable PFS, OS and LC outcomes to PA. SBRT should be considered as a curative intent therapy to avoid treatment stage migration in this favourable prognostic cohort of patients.

Definitive Stereotactic Body Radiation Therapy in Early-Stage Solitary Hepatocellular Carcinoma: An Australian Multi-Institutional Review of Outcomes

AIMS

Standard curative options for early-stage, solitary hepatocellular carcinoma (HCC) are often unsuitable due to liver dysfunction, comorbidities and/or tumour location. Stereotactic body radiation therapy (SBRT) has shown high rates of local control in HCC; however, limited data exist in the treatment-naïve, curative-intent setting. We report the outcomes of patients with solitary early-stage HCC treated with SBRT as first-line curative-intent therapy.

MATERIALS AND METHODS

A multi-institutional retrospective study of treatment-naïve patients with Barcelona Clinic Liver Cancer stage 0/A, solitary ≤5 cm HCC, Child-Pugh score (CPS) A liver function who underwent SBRT between 2010 and 2019 as definitive therapy. The primary end point was freedom from local progression. Secondary end points were progression-free survival, overall survival, rate of treatment-related clinical toxicities and change in CPS >1.

RESULTS

In total, 68 patients were evaluated, with a median follow-up of 20 months (range 3-58). The median age was 68 years (range 50-86); 54 (79%) were men, 62 (91%) had cirrhosis and 50 (74%) were Eastern Cooperative Oncology Group 0. The median HCC diameter was 2.5 cm (range 1.3-5) and the median prescription biologically effective dose with a tumour a/b ratio of 10 Gy (BED10) was 93 Gy (interquartile range 72-100 Gy). Two-year freedom from local progression, progression-free survival and overall survival were 94.3% (95% confidence interval 86.6-100%), 59.5% (95% confidence interval 46.3-76.4%) and 88% (95% confidence interval 79.2-97.6%), respectively. Nine patients (13.2%) experienced grade ≥2 treatment-related clinical toxicities. A rise >1 in CPS was observed in six cirrhotic patients (9.6%).

CONCLUSION

SBRT is an effective and well-tolerated option to consider in patients with solitary, early-stage HCC. Prospective, randomised comparative studies are warranted to further refine its role as a first-line curative-intent therapy.

Clinical consensus statement: Establishing the roles of locoregional and systemic therapies for the treatment of intermediate-stage hepatocellular carcinoma in Canada

BACKGROUND

Hepatocellular carcinoma (HCC) a leading cause of cancer mortality worldwide and approximately one-third of patients present with intermediate-stage disease. The treatment landscape of intermediate-stage HCC is rapidly evolving due to developments in local, locoregional and systemic therapies. Treatment recommendations focused on this heterogenous disease stage and that take into account the Canadian reality are lacking. To address this gap, a pan-Canadian group of experts in hepatology, transplant, surgery, radiation therapy, nuclear medicine, interventional radiology, and medical oncology came together to develop consensus recommendations on management of intermediate-stage HCC relevant to the Canadian context.

METHODS

A modified Delphi framework was used to develop consensus statements with strengths of recommendation and supporting levels of evidence graded using the AHA/ACC classification system. Tentative consensus statements were drafted based on a systematic search and expert input in a series of iterative feedback cycles and were then circulated via online survey to assess the level of agreement.

RESULTS & CONCLUSION

The pre-defined ratification threshold of 80 % agreement was reached for all statements in the areas of multidisciplinary treatment (n = 4), intra-arterial therapy (n = 14), biologics (n = 5), radiation therapy (n = 3), surgical resection and transplantation (n = 7), and percutaneous ablative therapy (n = 4). These generally reflected an expansion in treatment options due to developments in previously established or emergent techniques, introduction of new and more active therapies and increased therapeutic flexibility. These developments have allowed for greater treatment tailoring and personalization as well as a paradigm shift toward strategies with curative intent in a wider range of disease settings.

Role of Functional MRI in Liver SBRT: Current Use and Future Directions

Stereotactic body radiation therapy (SBRT) is an emerging treatment for liver cancers whereby large doses of radiation can be delivered precisely to target lesions in 3-5 fractions. The target dose is limited by the dose that can be safely delivered to the non-tumour liver, which depends on the baseline liver functional reserve. Current liver SBRT guidelines assume uniform liver function in the non-tumour liver. However, the assumption of uniform liver function is false in liver disease due to the presence of cirrhosis, damage due to previous chemo- or ablative therapies or irradiation, and fatty liver disease. Anatomical information from magnetic resonance imaging (MRI) is increasingly being used for SBRT planning. While its current use is limited to the identification of target location and size, functional MRI techniques also offer the ability to quantify and spatially map liver tissue microstructure and function. This review summarises and discusses the advantages offered by functional MRI methods for SBRT treatment planning and the potential for adaptive SBRT workflows.

Stereotactic Body Radiotherapy and Conventional Radiotherapy Induce Cytoskeleton Extension and Enlargement of Cell Morphology in Non-Small Cell Lung Cancer

Stereotactic body radiotherapy (SBRT) is now widely used in cancer therapy. However, the biological effects of SBRT compared with conventional radiotherapy (CRT) are not clear. The cytoskeleton plays an important role in many biological processes and cellular life activities. The effects of SBRT or CRT on the morphology and cytoskeletal structure of non-small cell lung cancer (NSCLC) cells remain unknown. Based on the biologically equivalent dose (BED) formula, we designed SBRT and CRT fractionation regimens with the same BED. The morphology was captured during radiation, and rhodamine-phalloidin immunofluorescence was used to study the cytoskeleton. A lactate dehydrogenase assay kit was used to determine the cell membrane permeability, and western blot was used to detect the cytoskeleton protein expression levels. The morphology and cytoskeleton expanded after SBRT or CRT, with an increase in cell membrane permeability and stable cytoskeleton protein levels. Besides, different dose of SBRT (10,20,30 Gy) induce similar morphology and cytoskeleton enlargement. Our findings indicate that SBRT and CRT can induce cytoskeleton reorganization and the enlargement of cell morphology (at different rates) in NSCLC. The morphology and cytoskeleton enlargement after SBRT are dose independence.

Stereotactic ablative radiotherapy for hepatocellular carcinoma: A systematic review and meta-analysis of local control, survival and toxicity outcomes

There is a growing body of literature supporting the use of stereotactic ablative body radiotherapy (SABR) in the management of primary hepatocellular carcinoma (HCC). This systematic review and meta-analysis of the current published evidence for SABR for HCC assessed the impact of treatment dose, fractionation and tumour size on the outcomes of local control (LC), overall survival (OS) and toxicity. A systematic search was independently performed by two authors for articles published in peer-reviewed journals between January 2005 and December 2019. A DerSimonian and Laird random effects model was used to assess pooled results. A multivariate meta-regression analysis incorporated the effect of explanatory variables (radiation dose in EQD2_[10], fractionation and tumour size) on outcomes of OS, LC and toxicity. Forty-nine cohorts involving 2846 HCC patients with 3088 lesions treated with SABR were included. Pooled 1-, 2- and 3-year LC rates were 91.1% (95% confidence interval [CI] 88.3-93.2), 86.7% (95% CI 82.7-89.8) and 84.2% (95% CI 77.9-88.9) respectively. Pooled 1-, 2- and 3-year OS rates were 78.4% (95% CI 73.4-82.6), 61.3% (55.2-66.9) and 48.3% (95% CI 39.0-57). Population-weighted median grade 3 toxicity rates were 6.5% (IQR 3.2-16) and mean grade 4/5 rates were 1.4% (IQR 0-2.1). Within EQD2_[10] ranges of 40 to 83.33 Gy corresponding to common dose-fractionation regimens of 30-50 Gy in 5 fractions, there was a multivariate association between superior LC and OS with increasing EQD2_[10] , with a proportionately smaller increase in grade 3 toxicity and no association with grade 4/5 toxicity. Stereotactic ablative body radiotherapy is a viable treatment option for HCC with high LC rates and low rates of reported grade 3/4 toxicity. Increasing EQD2_[10] was associated with improvements in LC and OS with a comparatively smaller increase in toxicity. Prospective randomised trials are warranted to define optimal patient selection and dose-fractionation regimens.