Process of development of decentralised clinical trial methodology for cancer clinical trials in Aotearoa New Zealand.

Aim: To develop processes for the development of decentralised clinical trial methodology for Aotearoa New Zealand, focussing on equity of access to cancer clinical trials for Māori, Pacific people, vulnerable communities and those in rural settings.

Methods: A national steering committee supported by Te Aho o Te Kahu - Cancer Control Agency was formed to: guide the adaptation and implementation of overseas decentralised clinical trial models to suit the needs of Aotearoa New Zealand with an equity focus; provide high-level oversight and expertise for direction and development of policies, procedures and infrastructure compliant with ICH GCP R2; and implement a national strategy.

Results: Twelve standard operating procedures were developed, as well as a supervision plan and a glossary.

The impact of rectal spacers in MR-guided adaptive radiotherapy.

Background And Purpose: The use of stereotactic ablative radiotherapy (SABR) for prostate cancer has increased significantly. However, SABR can elevate the risk of moderate gastrointestinal (GI) side effects. Rectal spacers mitigate this risk by reducing the rectal dose.

Impact of implementing stricter criteria for blood transfusion in patients with head and neck cancer undergoing free tissue transfer.

Objective: Recent literature studying the impact of blood transfusion on outcomes in patients with head and neck cancer (HNC) have shown that blood transfusions are associated with increased risk of death and higher wound infection rates. The purpose of this study was to implement a lower transfusion threshold while comparing outcomes of free flap patients following initiation of a new transfusion guideline.

Methods: A retrospective study of all patients at a tertiary care academic center who underwent free tissue transfer after HNC resection between July 17, 2007 and June 7, 2021.

Tools and recommendations for commissioning and quality assurance of deformable image registration in radiotherapy.

Multiple tools are available for commissioning and quality assurance of deformable image registration (DIR), each with their own advantages and disadvantages in the context of radiotherapy. The selection of appropriate tools should depend on the DIR application with its corresponding available input, desired output, and time requirement. Discussions were hosted by the ESTRO Physics Workshop 2021 on Commissioning and Quality Assurance for DIR in Radiotherapy.

Adapting outside the box: Simulation-free MR-guided stereotactic ablative radiotherapy for prostate cancer.

Background And Purpose: Magnetic resonance (MR)-guided radiotherapy (MRgRT) enhances treatment precision and adaptive capabilities, potentially supporting a simulation-free (sim-free) workflow. This work reports the first clinical implementation of a sim-free workflow using the MR-Linac for prostate cancer patients treated with stereotactic ablative radiotherapy (SABR).

Materials And Methods: Fifteen patients who had undergone a prostate-specific membrane antigen positron emission tomography/CT (PSMA-PET/CT) scan as part of diagnostic workup were included in this work.

Does a peer review group consensus process for MR-Linac patients affect clinical care? Evaluation of impact and feasibility.

Background And Purpose: Peer review is an important component of quality assurance in radiotherapy. To our knowledge, there are no studies reporting on the feasibility and outcomes of the peer review process for magnetic resonance (MR) guided radiotherapy (MRgRT) on the MR linear accelerator (MR-Linac) despite the planning complexity involved and its evolving clinical indications. This study aimed to quantify the rate of change in treatment plans post-peer review and the time and resources required.

Open-source hardware and software for the measurement, characterization, reporting, and correction of geometric distortion in MRI.

Background: Geometric distortion is a serious problem in MRI, particularly in MRI guided therapy. A lack of affordable and adaptable tools in this area limits research progress and harmonized quality assurance.

Purpose: To develop and test a suite of open-source hardware and software tools for the measurement, characterization, reporting, and correction of geometric distortion in MRI.

Evaluating the relationship between contouring variability and modelled treatment outcome for prostate bed radiotherapy.

Contouring similarity metrics are often used in studies of inter-observer variation and automatic segmentation but do not provide an assessment of clinical impact. This study focused on post-prostatectomy radiotherapy and aimed to (1) identify if there is a relationship between variations in commonly used contouring similarity metrics and resulting dosimetry and (2) identify the variation in clinical target volume (CTV) contouring that significantly impacts dosimetry.The study retrospectively analysed CT scans of 10 patients from the TROG 08.

Technical note: Cryostat transmission characterization for MR linac - temporal stability, clinical impact and change implementation.

Background: In the Unity MR linac (Elekta AB, Stockholm, Sweden), the radiation beam traverses the cryostat and the coil support structure. The resulting beam attenuation must be considered for output calibration and its variation with gantry angle must be characterized in the treatment planning system (TPS).

Purpose: The aim of this work was to investigate the impact of a change of the cryostat transmission characterization (CTC) curve, due to the helium level modification, on clinical treatment plan dosimetry and to report on the experience with the CTC curve update.

Magnetic resonance guided adaptive post prostatectomy radiotherapy: Accumulated dose comparison of different workflows.

Purpose: The aim of this study was to assess the use of magnetic resonance guided adaptive radiotherapy (MRgART) in the post-prostatectomy setting; comparing dose accumulation for our initial seven patients treated with fully adaptive workflow on the Unity MR-Linac (MRL) and with non-adaptive plans generated offline. Additionally, we analyzed toxicity in patients receiving treatment.

Methods: Seven patients were treated with MRgART.

Diagnostic Delay in HPV-Related Oropharyngeal Squamous Cell Carcinoma.

 Human papillomavirus-related (HPV + ) oropharyngeal squamous cell carcinoma (OPSCC) is increasing in incidence and presents diagnostic challenges given its unique clinical presentation.  The purpose of the present study is to characterize the impact of the unique clinical presentation of HPV-related OPSCC on delays in diagnosis.  Retrospective review of presenting symptoms and clinical characteristics of 284 patients with OPSCC treated from 2002-2014.

Selenium speciation studies in cancer patients to evaluate the responses of biomarkers of selenium status to different selenium compounds.

This work presents the first systematic comparison of selenium (Se) speciation in plasma from cancer patients treated orally with three Se compounds (sodium selenite, SS; L-selenomethionine, SeMet; or Se-methylselenocysteine, MSC) at 400 µg/day for 28 days. The primary goal was to investigate how these chemical forms of Se affect the plasma Se distribution, aiming to identify the most effective Se compound for optimal selenoprotein expression. This was achieved using methodology based on HPLC-ICP-MS after sample preparation/fractionation approaches.

Pairwise biosynthesis of ion channels stabilizes excitability and mitigates arrhythmias.

Coordinated expression of ion channels is crucial for cardiac rhythms, neural signaling, and cell cycle progression. Perturbation of this balance results in many disorders including cardiac arrhythmias. Prior work revealed association of mRNAs encoding cardiac Na1.

Glycerol contributes to tuberculosis susceptibility in male mice with type 2 diabetes.

Diabetes mellitus increases risk for tuberculosis disease and adverse outcomes. Most people with both conditions have type 2 diabetes, but it is unknown if type 1 and type 2 diabetes have identical effects on tuberculosis susceptibility. Here we show that male mice receiving a high-fat diet and streptozotocin to model type 2 diabetes, have higher mortality, more lung pathology, and higher bacterial burden following Mycobacterium tuberculosis infection compared to mice treated with streptozotocin or high-fat diet alone.

Towards simulation-free MR-linac treatment: utilizing male pelvis PSMA-PET/CT and population-based electron density assignments.

. This study aimed to investigate the dosimetric impact of using population-based relative electron density (RED) overrides in lieu of simulation computerized tomography (CT) in a magnetic resonance linear accelerator (MRL) workflow for male pelvis patients. Additionally, the feasibility of using prostate specific membrane antigen positron emission tomography/CT (PSMA-PET/CT) scans to assess patients' eligibility for this proposed workflow was examined.

Optimising the MR-Linac as a standard treatment modality.

The magnetic resonance linear accelerator (MR-Linac) offers a new treatment paradigm, providing improved visualisation of targets and organs at risk while allowing for daily adaptation of treatment plans in real time. Online MR-guided adaptive treatment has reduced treatment uncertainties; however, the additional treatment time and resource requirements may be a concern. We present our experience of integrating an MR-Linac into a busy department and provide recommendations for improved clinical and resource efficiency.

Changes in serial multiparametric MRI and FDG-PET/CT functional imaging during radiation therapy can predict treatment response in patients with head and neck cancer.

Objectives: To test if tumour changes measured using combination of diffusion-weighted imaging (DWI) MRI and FDG-PET/CT performed serially during radiotherapy (RT) in mucosal head and neck carcinoma can predict treatment response.

Methods: Fifty-five patients from two prospective imaging biomarker studies were analysed. FDG-PET/CT was performed at baseline, during RT (week 3), and post RT (3 months).

Management of rectal cancer in the era of total neoadjuvant therapy and watch and wait: A multidisciplinary team discussion at the Australasian Gastro-Intestinal Trials Group (AGITG) Annual Scientific Meeting 2022.

Rectal cancer is a common malignancy. The management of rectal cancer has recently evolved and has undergone a paradigm shift with the advent of treatment approaches such as total neoadjuvant therapy and the watch-and-wait approach. However, despite the recently available evidence, there is no consensus on the optimal management approach in the setting of locally advanced rectal cancer.

Mid-treatment 18F-FDG PET imaging changes in parotid gland correlates to radiation-induced xerostomia.

Background: The aim of this study was to measure functional changes in parotid glands using mid-treatment FDG-PET/CT and correlate early imaging changes to subsequent xerostomia in mucosal head and neck squamous cell carcinoma patients undergoing radiotherapy.

Materials And Methods: 56 patients from two prospective imaging biomarker studies underwent FDG-PET/CT at baseline and during radiotherapy (week 3). Both parotid glands were volumetrically delineated at each time point.

Impact of tumour region of interest delineation method for mid-treatment FDG-PET response prediction in head and neck squamous cell carcinoma undergoing radiotherapy.

Background: The aim of this study was to evaluate the impact of tumour region of interest (ROI) delineation method on mid-treatment F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) response prediction in mucosal head and neck squamous cell carcinoma during radiotherapy.

Methods: A total of 52 patients undergoing definitive radiotherapy with or without systemic therapy from two prospective imaging biomarker studies were analysed. FDG-PET was performed at baseline and during radiotherapy (week 3).

MR-Linac guided adaptive stereotactic ablative body radiotherapy for recurrent cardiac sarcoma with mitral valve bioprosthesis - a case report.

We present the first case in the literature of a 78-year-old woman with recurrent cardiac sarcoma adjacent to a bioprosthetic mitral valve treated with magnetic resonance linear accelerator (MR-Linac) guided adaptive stereotactic ablative body radiotherapy (SABR). The patient was treated using a 1.5 T Unity MR-Linac system (Elekta AB, Stockholm, Sweden).

ACPSEM position paper: the safety of magnetic resonance imaging linear accelerators.

Magnetic Resonance Imaging linear-accelerator (MRI-linac) equipment has recently been introduced to multiple centres in Australia and New Zealand. MRI equipment creates hazards for staff, patients and others in the MR environment; these hazards must be well understood, and risks managed by a system of environmental controls, written procedures and a trained workforce. While MRI-linac hazards are similar to the diagnostic paradigm, the equipment, workforce and environment are sufficiently different that additional safety guidance is warranted.