Investigating the effects of stereotactic body radiation therapy on pancreatic tumor hypoxia and microvasculature in an orthotopic mouse model using intravital fluorescence microscopy.

Despite decades of improvements in cytotoxic therapy, the current standard of care for locally advanced pancreatic cancer (LAPC) provides, on average, only a few months of survival benefit. Stereotactic Body Radiation Therapy (SBRT), a technique that accurately delivers high doses of radiation to tumors in fewer fractions, has emerged as a promising therapy to improve local control of LAPC; however, its effects on the tumor microenvironment and hypoxia remain poorly understood. To explore how SBRT affects pancreatic tumors, we combined an orthotopic mouse model of pancreatic cancer with an intravital microscopy platform to visualize changes to the in vivo tumor microenvironment in real-time.

Development of a Preclinical Double Model of Mandibular Irradiated Bone and Osteoradionecrosis in New Zealand Rabbits.

Purpose: Radiotherapy (RT) plays a crucial role in head and neck (HN) cancer treatment. Nevertheless, it can lead to serious and challenging adverse events such as osteoradionecrosis (ORN). A preclinical rabbit model of irradiated bone and ORN is herein proposed, with the aim to develop a viable model to be exploited for investigating new therapeutic approaches.

The Role of Stereotactic Body Radiotherapy in Oligoprogressive Malignant Disease (RADIANT): Oncologic Outcomes From a Phase 2 Nonrandomized Controlled Trial.

Purpose: In oligoprogressive (OP) cancer, there are a limited number of metastatic areas progressing on a background of stable or responding to widespread cancer. Although the standard of care for OP is changing systemic therapy (ST), stereotactic body radiation therapy (SBRT) is being explored as an alternative local therapy targeting the sites of progression.

Methods And Materials: RADIANT (NCT04122469) was a single-center phase 2 study of patients with metastatic genitourinary (GU), breast, and gastrointestinal (GI) cancers, receiving ST for ≥3 months, with radiographic OP disease in ≤5 sites.

Prospective evaluation of patient-reported anxiety and experiences with adaptive radiation therapy on an MR-linac.

Purpose: An integrated magnetic resonance scanner and linear accelerator (MR-linac) was implemented with daily online adaptive radiation therapy (ART). This study evaluated patient-reported experiences with their overall hospital care as well as treatment in the MR-linac environment.

Methods: Patients pre-screened for MR eligibility and claustrophobia were referred to simulation on a 1.

Clinical Outcomes of Patients with Metastatic Breast Cancer Treated with Hypo-Fractionated Liver Radiotherapy.

Purpose: To retrospectively review the clinical outcomes of patients with metastatic breast cancer (MBCa) following liver directed ablative intent radiotherapy (RT).

Methods: Demographics, disease and treatment characteristics of patients with MBCa who received liver metastasis (LM) directed ablative RT between 2004-2020 were analysed. The primary outcome was local control (LC), secondary outcomes included overall survival (OS) and progression-free survival (PFS) analyzed by univariate (UVA) and multi-variable analysis (MVA).

Practice-based training strategy for therapist-driven prostate MR-Linac adaptive radiotherapy.

Purpose: To develop a practice-based training strategy to transition from radiation oncologist to therapist-driven prostate MR-Linac adaptive radiotherapy.

Methods And Materials: In phase 1, 7 therapists independently contoured the prostate and organs-at-risk on T2-weighted MR images from 11 previously treated MR-Linac prostate patients. Contours were evaluated quantitatively (i.

Evaluation of dosimetric predictors of toxicity after IMRT with concurrent chemotherapy for anal cancer.

Background: This study investigates the impact of dosimetric parameters on acute and late toxicity for patients with anal squamous cell carcinoma (SCC) treated with image-guided intensity modulated radiation therapy (IG-IMRT) and concurrent chemotherapy.

Materials And Methods: Patients were enrolled in an observational cohort study between 2008 and 2013 (median follow-up 3.4 years).

The Impact of Disease Progression on Health-Related Quality of Life Outcomes in Patients With Oligometastatic Disease at 12 Months Post Stereotactic Body Radiation Therapy.

Purpose: There is a paucity of published health-related quality of life (HRQOL) outcomes in patients with oligometastatic disease (OMD) who receive stereotactic body radiation therapy (SBRT) and no available data assessing the effect of disease progression post-SBRT on HRQOL in this patient population.

Methods And Materials: Patients with OMD who received SBRT in a phase II single-arm research ethics board approved study were included. HRQOL was a secondary outcome.

Patient-Reported and Clinical Outcomes From 5-Fraction SBRT for Oligometastases: A Prospective Single-Institution Study.

Purpose: To describe the long-term outcomes of a 5-fraction normal tissue tolerance adapted strategy for the management of oligometastases (OM).

Methods And Materials: Patients with histologically confirmed solid tumors, ≤5 extracranial metastases, suitable for a definitive approach for all metastatic lesions, at least one lesion suitable for Stereotactic Body Radiotherapy (SBRT), Eastern Coooperative Oncology Group Performance Status ≤2 were eligible. Treatment intervention was a 5-fraction (25-55 Gy) normal tissue adapted dosing strategy.

Assessing the Accuracy of Bioluminescence Image-Guided Stereotactic Body Radiation Therapy of Orthotopic Pancreatic Tumors Using a Small Animal Irradiator.

Stereotactic body radiation therapy (SBRT) has shown promising results in the treatment of pancreatic cancer and other solid tumors. However, wide adoption of SBRT remains limited largely due to uncertainty about the treatment's optimal fractionation schedules to elicit maximal tumor response while limiting the dose to adjacent structures. A small animal irradiator in combination with a clinically relevant oncological animal model could address these questions.

Impact of Definitive Chemoradiation on Quality-of-Life Changes for Patients With Anal Cancer: Long-term Results of a Prospective Study.

Background: Maintaining and improving quality of life (QOL) are important goals of anal cancer management. This disease is generally curable, with many long-term survivors.

Objective: Long-term QOL after chemoradiation for patients with anal cancer was evaluated.

Limited-stage small cell lung cancer: Outcomes associated with prophylactic cranial irradiation over a 20-year period at the Princess Margaret Cancer Centre.

Background & Purpose: Prophylactic cranial irradiation (PCI) is recommended for limited-stage small-cell lung cancer (LS-SCLC) patients with good response to concurrent chemoradiation. We report our institution's 20-year experience with this patient population and associated clinical outcomes.

Materials & Methods: A retrospective cohort of consecutive LS-SCLC patients treated with curative intent chemoradiation at our institution (1997-2018) was reviewed.

Implementation of Cardiac Stereotactic Radiotherapy: From Literature to the Linac.

Stereotactic radiotherapy (SBRT) has been applied to treat cardiac arrhythmias, but our institution had not yet implemented this technique. Here, we explain how we used implementation science and knowledge translation to provide cardiac SBRT to a critically ill patient with malignancy-associated refractory ventricular tachycardia. We reviewed the critical factors that enabled the implementation of this urgent treatment, such as the context of the implementation, the characteristics of the intervention, and the stakeholders.

Simulated daily plan adaptation for magnetic resonance-guided liver stereotactic body radiotherapy.

Introduction: Liver cancers are challenging to treat using image-guided radiotherapy (IGRT) due to motion and deformation of target volumes and organs at risk (OARs), as well as difficulties in visualising liver tumours using cone-beam computed tomography (CBCT) based IGRT. Liver cancer patients may thus benefit from magnetic resonance (MR)-guided daily adaptive re-planning. We evaluated the dosimetric impact of a daily plan adaptation strategy based on daily MR imaging versus CBCT-based IGRT.

A Mail Audit Independent Peer Review System for Dosimetry Verification of a Small Animal Irradiator.

Dedicated precision orthovoltage small animal irradiators have become widely available in the past decade and are commonly used for radiation biology research. However, there is a lack of dosimetric standardization among these irradiators, which affects the reproducibility of radiation-based animal studies. The purpose of this study was to develop a mail-based, independent peer review system to verify dose delivery among institutions using X-RAD 225Cx irradiators (Precision X-Ray, North Branford, CT).

Quantifying Reoxygenation in Pancreatic Cancer During Stereotactic Body Radiotherapy.

Hypoxia, the state of low oxygenation that often arises in solid tumours due to their high metabolism and irregular vasculature, is a major contributor to the resistance of tumours to radiation therapy (RT) and other treatments. Conventional RT extends treatment over several weeks or more, and nominally allows time for oxygen levels to increase ("reoxygenation") as cancer cells are killed by RT, mitigating the impact of hypoxia. Recent advances in RT have led to an increase in the use stereotactic body radiotherapy (SBRT), which delivers high doses in five or fewer fractions.

MRI-Based Upper Abdominal Organs-at-Risk Atlas for Radiation Oncology.

Purpose: The purpose of our study was to provide a guide for identification and contouring of upper abdominal organs-at-risk (OARs) in the setting of online magnetic resonance imaging (MRI)-guided radiation treatment planning and delivery.

Methods And Materials: After a needs assessment survey, it was determined that an upper abdominal MRI-based atlas of normal OARs would be of benefit to radiation oncologists and radiation therapists. An anonymized diagnostic 1.

Baseline Albumin-Bilirubin (ALBI) Score in Western Patients With Hepatocellular Carcinoma Treated With Stereotactic Body Radiation Therapy (SBRT).

Purpose: To assess the baseline albumin-bilirubin (ALBI) score as a predictor of toxicity and survival in a prospective cohort of Western patients with hepatocellular carcinoma (HCC) treated with stereotactic body radiation therapy (SBRT) in 2 prospective trials.

Methods And Materials: The study included 102 patients with Child-Pugh class A liver disease who received 6-fraction SBRT for HCC. Univariate and multivariable logistic regression investigated factors associated with toxicity, defined as an increase in Child-Pugh score ≥ 2 within 3 months of SBRT.

Spatial frequency performance limitations of radiation dose optimization and beam positioning.

The flexibility and sophistication of modern radiotherapy treatment planning and delivery methods have advanced techniques to improve the therapeutic ratio. Contemporary dose optimization and calculation algorithms facilitate radiotherapy plans which closely conform the three-dimensional dose distribution to the target, with beam shaping devices and image guided field targeting ensuring the fidelity and accuracy of treatment delivery. Ultimately, dose distribution conformity is limited by the maximum deliverable dose gradient; shallow dose gradients challenge techniques to deliver a tumoricidal radiation dose while minimizing dose to surrounding tissue.

The ongoing challenge of large anal cancers: prospective long term outcomes of intensity-modulated radiation therapy with concurrent chemotherapy.

Purpose: Patterns of failure and long term outcomes were prospectively evaluated following tumor factors-stratified radiation dose for anal/perianal cancer.

Methods: Between 2008-2013, patients with anal/perianal squamous cell carcinoma were accrued to an institutional REB-approved prospective study. All patients were treated with image-guided intensity-modulated radiation therapy (IG-IMRT).

Low Incidence of Esophageal Toxicity After Lung Stereotactic Body Radiation Therapy: Are Current Esophageal Dose Constraints Too Conservative?

Purpose: To explore and quantify the relationship between esophageal dose and toxicity in the setting of lung stereotactic body radiation therapy (SBRT).

Methods And Materials: This analysis was conducted on the basis of a prospective study of patients treated with SBRT at our institution from October 2004 to December 2015. Most patients were treated with 54 Gy/3 fractions, 48 Gy/4 fractions alternate days, or 60 Gy/8 fractions daily.

Impact of Pretreatment Interstitial Lung Disease on Radiation Pneumonitis and Survival in Patients Treated With Lung Stereotactic Body Radiation Therapy (SBRT).

Introduction: The purpose of this study was to determine the impact of interstitial lung disease (ILD) on radiation pneumonitis (RP) and overall survival (OS) in lung stereotactic body radiation therapy (SBRT).

Methods: Patients treated with lung SBRT from 2004 to 2015 were included. Pretreatment computed tomography scans were reviewed and classified for interstitial changes by thoracic radiologists using American Thoracic Society guidelines and Washko and Kazerooni scores.