Poster Presentation NSW State Cancer Conference 2023

Personalised liver stereotactic body radiation therapy using magnetic resonance imaging: The PRISM clinical trial (#325)

Sirisha Tadimalla 1 , Tim Wang 2 , Val Gebski 3 , Sheryl Foster 4 5 , Vincent Lam 6 , Robert Finnegan 1 7 8 , Jonathan Sykes 2 , Jacob George 9 , Verity Ahern 2 , Steven Sourbron 10 , Annette Haworth 1
  1. Institute of Medical Physics, The University of Sydney, Camperdown, NSW, Australia
  2. Sydney West Radiation Oncology Network, Western Sydney Local Health District, Westmead, NSW, Australia
  3. NHMRC Clinical Trials Centre, The University of Sydney , Sydney, NSW, Australia
  4. Department of Radiology, Westmead Hospital, Westmead, NSW, Australia
  5. Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney , Camperdown, NSW, Australia
  6. Acute Surgical Unit, Westmead Hospital, Westmead, NSW, Australia
  7. Ingham Institute of Applied Research, Liverpool, Australia
  8. Northern Sydney Cancer Center, Royal North Shore Hospital, St Leonards, NSW, Australia
  9. Department of Gastroenterology and Hepatology, Westmead Hospital, Westmead, NSW, Australia
  10. Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK

Introduction: Stereotactic body radiation therapy (SBRT) is increasingly used as a treatment option for patients with hepatocellular carcinoma (HCC). Baseline liver function, typically described by the Child-Pugh (CP) score, determines the dose constraints to the non-tumour liver, in turn limiting the dose delivered to the gross tumour volume (GTV) [1]. Therefore, for many patients with impaired overall liver function, SBRT is offered as a palliative option. However, patients with HCC can have a high degree of spatial variation in liver function due to underlying cirrhosis and response to dose distributions during early SBRT fractions. Heterogeneity in liver function is not currently considered in SBRT planning.

The Personalised liver SBRT using magnetic resonance imaging (PRISM) study will investigate an alternative approach where liver function will be spatially mapped using magnetic resonance imaging (MRI) to create function-based treatment plans that minimise dose to high functioning regions of the liver, while sacrificing low functioning liver to maximise GTV dose. The feasibility of a) identifying regions of high and low liver function using MRI, b) creating SBRT treatment plans guided by liver function maps, c) mid-treatment adaptation using mid-treatment MRI will be investigated in the PRISM clinical trial.

 Methods: 30 participants undergoing liver SBRT will be recruited in 3 stages: Stage 1 will optimize study design (5 participants); Stage 2 will evaluate the potential of MRI to distinguish high and low functioning regions of the liver and spatially define changes in liver function after irradiation (10 participants); remaining recruitment will be completed in Stage 3 (15 participants). All participants will undergo pre-, mid-, and 3-month post-treatment MRI scans for liver function mapping. Indocyanine green (ICG) clearance test will be performed prior to each MRI scan as surrogate measure of global liver function [2].

 Analysis and Study Progress: Descriptive summaries (including 95% confidence intervals) of participants in each stage will be provided to inform the feasibility and design of future studies.The study has received ethics approval (WSLHD-HREC: 2022/ETH00203) and local site governance approvals. An MRI protocol specifically for the spatial mapping of liver function has been developed. The study has received funding and will commence participant recruitment in July 2023. 

 Conclusions: The PRISM clinical trial will evaluate the feasibility of personalization of liver SBRT using MRI for patients with liver cancer. Multi-centre participation is proposed following successful completion of the feasibility study.

  1. Liu et al., Stereotactic body radiotherapy in the management of hepatocellular carcinoma, JMIRO, 65, 365–373 (2021)
  2. Suresh et al., Using Indocyanine Green Extraction to Predict Liver Function, Int. J. Radiat. Oncol. 100, 131–137 (2018)