Interobserver variability in target volume delineation for CT/MRI simulation and MRI-guided adaptive radiotherapy in rectal cancer.

Objectives: Quantify target volume delineation uncertainty for CT/MRI simulation and MRI-guided adaptive radiotherapy in rectal cancer. Define optimal imaging sequences for target delineation.

Methods: Six experienced radiation oncologists delineated clinical target volumes (CTVs) on CT and 2D and 3D-MRI in three patients with rectal cancer, using consensus contouring guidelines.

Monte Carlo calculation of detector perturbation and quality correction factors in a 1.5 T magnetic resonance guided radiation therapy small photon beams.

With future advances in magnetic resonance imaging-guided radiation therapy, small photon beams are expected to be included regularly in clinical treatments. This study provides physical insights on detector dose-response to multiple megavoltage photon beam sizes coupled to magnetic fields and determines optimal orientations for measurements.Monte Carlo simulations determine small-cavity detector (solid-state: PTW60012 and PTW60019, ionization chambers: PTW31010, PTW31021, and PTW31022) dose-responses in water to an Elekta Unity 7 MV FFF photon beam.

ATARI trial: ATR inhibitor in combination with olaparib in gynecological cancers with ARID1A loss or no loss (ENGOT/GYN1/NCRI).

Background: ARID1A (AT-rich interactive domain containing protein 1A) loss-of-function mutations have been reported in gynecological cancers, including rarer subtypes such as clear cell carcinoma. Preclinical studies indicate that mutant cancers display sensitivity to ATR inhibition while tumors without mutations may be sensitive to Ataxia telangiectasia and Rad3 related (ATR) inhibitors in combination with poly-ADP ribose polymerase (PARP) inhibitors.

Primary Objective: To determine whether the ATR inhibitor, ceralasertib, has clinical activity as a single agent and in combination with the PARP inhibitor, olaparib, in patients with ARID1A 'loss' and 'no loss' clear cell carcinomas and other relapsed gynecological cancers.

Echo time dependence of biexponential and triexponential intravoxel incoherent motion parameters in the liver.

Purpose: Intravoxel incoherent motion (IVIM) studies are performed with different acquisition protocols. Comparing them requires knowledge of echo time (TE) dependencies. The TE-dependence of the biexponential perfusion fraction f is well-documented, unlike that of its triexponential counterparts f and f and the biexponential and triexponential pseudodiffusion coefficients D , , and .

Assessing measurement invariance in the EORTC QLQ-C30.

Purpose: We aimed to investigate measurement invariance (MI) in the European Organisation for research and treatment of cancer quality of life questionnaire core 30 (EORTC QLQ-C30) in a heterogeneous sample of patients with cancer.

Methods: Data from 12 studies within the PROFILES registry were used for secondary analyses (n = 7007). We tested MI by successive restrictions on thresholds, loadings, and intercepts across subgroups based on primary cancer sites, age, sex, time since diagnosis, and life stage, using multigroup confirmatory factor analysis (MGCFA) for ordered categorical measures.

Quantitative prediction of the extent of pelvic tumour ablation by magnetic resonance-guided high intensity focused ultrasound.

Background: Patient suitability for magnetic resonance-guided high intensity focused ultrasound (MRgHIFU) therapy of pelvic tumors is currently assessed by visual estimation of the proportion of tumor that can be reached by the device's focus (coverage). Since it is important to assess whether enough energy reaches the tumor to achieve ablation, a methodology for estimating the proportion of the tumor that can be ablated (treatability) was developed. Predicted treatability was compared against clinically achieved thermal ablation.

Efficacy and Safety of Cabazitaxel Versus Abiraterone or Enzalutamide in Older Patients with Metastatic Castration-resistant Prostate Cancer in the CARD Study.

Background: In the CARD study (NCT02485691), cabazitaxel significantly improved median radiographic progression-free survival (rPFS) and overall survival (OS) versus abiraterone/enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) who had previously received docetaxel and progressed ≤12 mo on the alternative agent (abiraterone/enzalutamide).

Objective: To assess cabazitaxel versus abiraterone/enzalutamide in older (≥70 yr) and younger (<70 yr) patients in CARD.

Design, Setting, And Participants: Patients with mCRPC were randomized 1:1 to cabazitaxel (25 mg/m plus prednisone and granulocyte colony-stimulating factor) versus abiraterone (1000 mg plus prednisone) or enzalutamide (160 mg).

Integration of quantitative imaging biomarkers in clinical trials for MR-guided radiotherapy: Conceptual guidance for multicentre studies from the MR-Linac Consortium Imaging Biomarker Working Group.

Quantitative imaging biomarkers (QIBs) derived from MRI techniques have the potential to be used for the personalised treatment of cancer patients. However, large-scale data are missing to validate their added value in clinical practice. Integrated MRI-guided radiotherapy (MRIgRT) systems, such as hybrid MRI-linear accelerators, have the unique advantage that MR images can be acquired during every treatment session.

Beyond the Androgen Receptor: The Sequence, the Mutants, and New Avengers in the Treatment of Castrate-Resistant Metastatic Prostate Cancer.

Targeting the androgen receptor by depriving testosterone with gonadotropin-releasing hormone agonists or antagonists, or surgical castration, has been the backbone of metastatic prostate cancer treatment. Although most prostate cancers initially respond to androgen deprivation, metastatic castration-resistant prostate cancer evolves into a heterogeneous disease with diverse drivers of progression and mechanisms of therapeutic resistance. Development of castrate resistance phenotype is associated with lethality despite the recent noteworthy strides gained via increase in therapeutic options.

Traceable reference dosimetry in MRI guided radiotherapy using alanine: calibration and magnetic field correction factors of ionisation chambers.

Magnetic resonance imaging (MRI)-guided radiotherapy (RT) (MRIgRT) falls outside the scope of existing high energy photon therapy dosimetry protocols, because those protocols do not consider the effects of the magnetic field on detector response and on absorbed dose to water. The aim of this study is to evaluate and demonstrate the traceable measurement of absorbed dose in MRIgRT systems using alanine, made possible by the characterisation of alanine sensitivity to magnetic fields reported previously by Billas(2020115001), in a way which is compatible with existing standards and calibrations available for conventional RT. In this study, alanine is used to transfer absorbed dose to water to MRIgRT systems from a conventional linac.

Ultrasound-Responsive Nanocarriers in Cancer Treatment: A Review.

The safe and effective delivery of anticancer agents to diseased tissues is one of the significant challenges in cancer therapy. Conventional anticancer agents are generally cytotoxins with poor pharmacokinetics and bioavailability. Nanocarriers are nanosized particles designed for the selectivity of anticancer drugs and gene transport to tumors.

Rapid 4D-MRI reconstruction using a deep radial convolutional neural network: Dracula.

Background And Purpose: 4D and midposition MRI could inform plan adaptation in lung and abdominal MR-guided radiotherapy. We present deep learning-based solutions to overcome long 4D-MRI reconstruction times while maintaining high image quality and short scan times.

Methods: Two 3D U-net deep convolutional neural networks were trained to accelerate the 4D joint MoCo-HDTV reconstruction.

Inter-Observer Variation in Delineating the Pharyngeal Constrictor Muscle as Organ at Risk in Radiotherapy for Head and Neck Cancer.

Background And Purpose: To evaluate the inter-observer variation (IOV) in pharyngeal constrictor muscle (PCM) contouring, and resultant impact on dosimetry and estimated toxicity, as part of the pre-trial radiotherapy trial quality assurance (RTQA) within DARS, a multicenter phase III randomized controlled trial investigating the functional benefits of dysphagia-optimized intensity-modulated radiotherapy (Do-IMRT) in pharyngeal cancers.

Methods And Materials: Outlining accuracy of 15 clinicians' superior and middle PCM (SMPCM) and inferior PCM (IPCM) were retrospectively assessed against gold standards (GS) using volume, location, and conformity indices (CIs) on a pre-trial benchmark case of oropharyngeal cancer. The influence of delineation variability on dose delivered to the constrictor muscles with Do-IMRT and resultant normal tissue complication probability (NTCP) for physician-scored radiation-associated dysphagia at 6 months was evaluated.

Cabazitaxel versus abiraterone or enzalutamide in metastatic castration-resistant prostate cancer: post hoc analysis of the CARD study excluding chemohormonal therapy for castrate-naive disease.

Background: In the CARD study (NCT02485691), cabazitaxel significantly improved clinical outcomes versus abiraterone or enzalutamide in patients with metastatic castration-resistant prostate cancer previously treated with docetaxel and the alternative androgen-signalling-targeted inhibitor. However, some patients received docetaxel or the prior alternative androgen-signalling-targeted inhibitor in the metastatic hormone-sensitive (mHSPC) setting. Therefore, the CARD results cannot be directly translated to a Japanese population.

Optimisation of a composite difference metric for prompt error detection in real-time portal dosimetry of simulated volumetric modulated arc therapy.

Objectives: In real-time portal dosimetry, thresholds are set for several measures of difference between predicted and measured images, and signals larger than those thresholds signify an error. The aim of this work is to investigate the use of an additional composite difference metric (CDM) for earlier detection of errors.

Methods: Portal images were predicted for the volumetric modulated arc therapy plans of six prostate patients.

An Inter-observer Study to Determine Radiotherapy Planning Target Volumes for Recurrent Gynaecological Cancer Comparing Magnetic Resonance Imaging Only With Computed Tomography-Magnetic Resonance Imaging.

Aims: Target delineation uncertainty is arguably the largest source of geometric uncertainty in radiotherapy. Several factors can affect it, including the imaging modality used for delineation. It is accounted for by applying safety margins to the target to produce a planning target volume (PTV), to which treatments are designed.

Practical considerations for optimising homologous recombination repair mutation testing in patients with metastatic prostate cancer.

Analysis of the genomic landscape of prostate cancer has identified different molecular subgroups with relevance for novel or existing targeted therapies. The recent approvals of the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and rucaparib in the metastatic castration-resistant prostate cancer (mCRPC) setting signal the need to embed molecular diagnostics in the clinical pathway of patients with mCRPC to identify those who can benefit from targeted therapies. Best practice guidelines in overall biospecimen collection and processing for molecular analysis are widely available for several tumour types.

Machine QA for the Elekta Unity system: A Report from the Elekta MR-linac consortium.

Over the last few years, magnetic resonance image-guided radiotherapy systems have been introduced into the clinic, allowing for daily online plan adaption. While quality assurance (QA) is similar to conventional radiotherapy systems, there is a need to introduce or modify measurement techniques. As yet, there is no consensus guidance on the QA equipment and test requirements for such systems.

Denosumab compared with zoledronic acid on PFS in multiple myeloma: exploratory results of an international phase 3 study.

An exploratory end point from a recent trial in patients with newly diagnosed multiple myeloma showed that median progression-free survival (PFS) was increased by 10.7 months with denosumab vs zoledronic acid. We performed additional analyses to identify factors that may have contributed to the favorable PFS with denosumab.

New target volume delineation and PTV strategies to further personalise radiotherapy.

Target volume delineation uncertainty (DU) is arguably one of the largest geometric uncertainties in radiotherapy that are accounted for using planning target volume (PTV) margins. Geometrical uncertainties are typically derived from a limited sample of patients. Consequently, the resultant margins are not tailored to individual patients.

MRI texture feature repeatability and image acquisition factor robustness, a phantom study and in silico study.

Purpose: To evaluate robustness and repeatability of magnetic resonance imaging (MRI) texture features in water and tissue phantom test-retest study.

Materials And Methods: Separate water and tissue phantoms were imaged twice with the same protocol in a test-retest experiment using a 1.5-T scanner.

Professional quality of life and burnout among medical physicists working in radiation oncology: The role of alexithymia and empathy.

Background And Purpose: The professional quality of life of radiation oncology professionals can be influenced by different contributing factors, including personality traits. Alexithymia involves deficits in emotion processing and awareness. Empathy is the ability to understand another's 'state of mind/emotion'.

A treatment planning study of combined carbon ion-beam plus photon intensity-modulated radiotherapy.

Background And Purpose: Combined photon intensity-modulated radiotherapy (IMRT) and sequential dose-escalated carbon ion beam therapy (IBT) is a technically advanced treatment option for head and neck malignancies. We proposed and evaluated an integrated planning strategy as opposed to an established and largely separated planning workflow.

Materials And Methods: Ten patients with representative malignancies of the head and neck region underwent combined carbon-photon radiotherapy (RT) in our facilities.