Association of Patient Comorbidities with Treatment Regret Among Patients with Localized Prostate Cancer - Results from a Population-Based Cohort.

Objectives: Decision regret is a well-established, negative outcome in prostate cancer. We hypothesized that baseline comorbidities, which impact treatment tolerability, are associated with regret.

Materials And Methods: In a prospective, population-based cohort of prostate cancer patients, patient-reported regret was assessed at 12 months after treatment using a validated measure.

Short- and long-term weekly patient-reported outcomes prediction undergoing radiotherapy: single-patient time series model vs. transformer-based multi-patient time series model.

Background: Patient-reported outcomes (PROs) are direct reports from patients on health status, symptoms, quality of life, or treatment satisfaction, offering critical insights into subjective experiences that clinical metrics may overlook. Accurately predicting personalized short- and long-term weekly PROs during radiotherapy is essential for monitoring health status, optimizing treatment efficacy, and enabling timely interventions to manage side effects.

Methods: Based on the well-documented prostate cancer PRO dataset with 17 patients after pre-processing, this study evaluates single-patient time series models (i.

Estimates of cardiac implanted electronic device neutron dose for a pencil beam scanning proton therapy system.

Background: The presence of a cardiovascular implantable electronic device (CIED) is frequently viewed as a contraindication to proton therapy due to the creation of secondary neutrons that can potentially damage CIED electronics. As a result, photon therapy is typically recommended for patients with CIEDs.

Purpose: The study aims to provide a method for estimating neutron dose to a CIED by measuring equivalent neutron dose at varying distances from isocenter and field edge.

Optimizing normal tissue sparing via spatiotemporal optimization under equivalent tumor-radical efficacy.

Spatiotemporal optimization in radiation therapy involves determining the optimal number of dose delivery fractions (temporal) and the optimal dose per fraction (spatial). Traditional approaches focus on maximizing the biologically effective dose (BED) to the target while constraining BED to organs-at-risk (OAR), which may lead to insufficient BED for complete tumor cell kill. This work proposes a formulation that ensures adequate BED delivery to the target while minimizing BED to the OAR.

Incorporating organ deformation in biological modeling and patient outcome study for permanent prostate brachytherapy.

Permanent prostate brachytherapy has inherent intraoperative organ deformation due to the inflatable trans-rectal ultrasound probe cover. Since the majority of the dose is delivered postoperatively with no deformation, the dosimetry approved at the time of implant may not accurately represent the dose delivered to the target and organs at risk. We aimed to evaluate the biological effect of the prostate deformation and its correlation with patient-reported outcomes.

Thromboembolic Events in Castration-Resistant Prostate Cancer Patients With and Without Cardiovascular Comorbidities Receiving Oral Androgen Receptor Pathway Inhibitors.

Background: This study investigates the association between thromboembolic events (TE) and castration-resistant prostate cancer (CRPC) patients receiving oral androgen receptor pathway inhibitors (ARPi) compared to those undergoing chemotherapy, both with and without a pre-existing history of cardiovascular disease (CVD).

Methods: A total of 2779 men diagnosed with CRPC were identified using the Surveillance, Epidemiology, and End Results (SEER) Medicare Linked Database from 2012 to 2016. Patients were stratified based on their CVD history.

Characterization of commercial detectors for absolute proton UHDR dosimetry on a compact clinical proton synchrocyclotron.

Background: Modern compact proton synchrocyclotrons can achieve ultra-high dose rates ( 40 Gy/s) to support ultra-high-dose-rate (UHDR) preclinical experiments utilizing pencil beam scanning (PBS) protons. Unique to synchrocyclotrons is a pulsed proton time structure as compared to the quasi-continuous nature of other proton accelerators like isochronous cyclotrons. Thus, high instantaneous proton currents in the order of several µA must be generated to achieve UHDRs.

Treatment switching between Enzalutamide and Abiraterone Acetate and time to oral opioid initiation in castration-resistant prostate cancer patients.

Background And Aims: Enzalutamide (ENZ) and Abiraterone Acetate (AA) are both first-line treatments for castration-resistant prostate cancer (CRPC). CRPC patients may switch from ENZ to AA or from AA to ENZ, if they do not respond well to the treatment, or experience intolerable side effects. This study examine treatment switching from ENZ to AA or from AA to ENZ, while investigating death as a competing risk.

Real-world survival and economic burden among patients with locally advanced or metastatic urothelial carcinoma in the United States.

Background: Given the changing treatment landscape for locally advanced or metastatic urothelial carcinoma (la/mUC), this study aimed to describe real-world treatments, overall survival (OS), health care resource utilization (HCRU), and costs among US patients with la/mUC receiving first-line therapy.

Methods: This retrospective study was conducted using 100% Medicare claims data (2015-2020). Patients with la/mUC were selected; initiation of first-line therapy was the index date.

Multi-IMPT: a biologically equivalent approach to proton ARC therapy.

Objective: Proton spot-scanning arc therapy (ARC) is an emerging modality that can improve the high-dose conformity to targets compared with standard intensity-modulated proton therapy (IMPT). However, the efficient treatment delivery of ARC is challenging due to the required frequent energy changes during the continuous gantry rotation. This work proposes a novel method that delivers a multiple IMPT (multi-IMPT) plan that is equivalent to ARC in terms of biologically effective dose (BED).

Eligibility and Endpoints for Clinical Trials in Trimodality Therapy for Bladder Cancer.

Background: Trimodality therapy (TMT) is a viable option for muscle-invasive localized bladder cancer, providing an alternative to radical cystectomy in properly selected patients. The approval of novel therapeutics in different stages of bladder cancer treatment has sparked interest in exploring concurrent systemic therapies with radiation in clinical trials to enhance long-term outcomes. Achieving uniformity in trial eligibility criteria and endpoint definitions is imperative in describing clinical significance, comparing trials, and changing standard of care guidelines.

Reirradiation of Utracentrally Located Thoracic Tumors Using a 10-Fraction Hypofractionated Stereotactic Body Radiation Therapy Course: A Detailed Dosimetric Analysis.

Purpose: There is very little information detailing outcomes and toxicity following reirradiation for ultracentrally located thoracic tumors, and detailed dosimetric data are nonexistent. These data are critical for the safe management of these extremely difficult cases.

Methods And Materials: The records of 15 individuals undergoing 10-fraction hypofractionated stereotactic body radiation therapy for the management of ultracentrally located thoracic tumors between 2009 and 2020 at a single institution were retrospectively reviewed.

Feasibility of Pay for Performance and Transparency Interventions on the Selection and Quality of Observational Management for Patients With Low-Risk Prostate Cancer in the Community Practice.

Introduction: Practice-level strategies to improve the use of conservative management for low-risk prostate cancer have not been rigorously evaluated. We examined the feasibility of implementation and preliminary outcomes of a pay-for-performance (P4P) and a transparency intervention at the practice level.

Methods: We conducted a pilot study within a Southern California urology practice network.

Proton ARC based LATTICE radiation therapy: feasibility study, energy layer optimization and LET optimization.

LATTICE, a spatially fractionated radiation therapy (SFRT) modality, is a 3D generalization of GRID and delivers highly modulated peak-valley spatial dose distribution to tumor targets, characterized by peak-to-valley dose ratio (PVDR). Proton LATTICE is highly desirable, because of the potential synergy of the benefit from protons compared to photons, and the benefit from LATTICE compared to GRID. Proton LATTICE using standard proton RT via intensity modulated proton therapy (IMPT) (with a few beam angles) can be problematic with poor target dose coverage and high dose spill to organs-at-risk (OAR).

TEAM: Triangular-mEsh Adaptive and Multiscale proton spot generation method.

Background: Proton therapy is preferred for its dose conformality to spare normal tissues and organs-at-risk (OAR) via Bragg peaks with negligible exit dose. However, proton dose conformality can be further optimized: (1) the spot placement is based on the structured (e.g.

2V-CBCT: Two-Orthogonal-Projection Based CBCT Reconstruction and Dose Calculation for Radiation Therapy Using Real Projection Data.

This work demonstrates the feasibility of two-orthogonal-projection-based CBCT (2V-CBCT) reconstruction and dose calculation for radiation therapy (RT) using real projection data, which is the first 2V-CBCT feasibility study with real projection data, to the best of our knowledge. RT treatments are often delivered in multiple fractions, for which on-board CBCT is desirable to calculate the delivered dose per fraction for the purpose of RT delivery quality assurance and adaptive RT. However, not all RT treatments/fractions have CBCT acquired, but two orthogonal projections are always available.

A novel treatment planning method via scissor beams for uniform-target-dose proton GRID with peak-valley-dose-ratio optimization.

Background: Proton spatially fractionated RT (SFRT) can potentially synergize the unique advantages of using proton Bragg peak and SFRT peak-valley dose ratio (PVDR) to reduce the radiation-induced damage for normal tissues. Uniform-target-dose (UTD) proton GRID is a proton SFRT modality that can be clinically desirable and conveniently adopted since its UTD resembles target dose distribution in conventional proton RT (CONV). However, UTD proton GRID is not used clinically, which is likely due to the lack of an effective treatment planning method.

Why is a small sample size not enough?

Background: Clinical studies are often limited by resources available, which results in constraints on sample size. We use simulated data to illustrate study implications when the sample size is too small.

Methods And Results: Using 2 theoretical populations each with N = 1000, we randomly sample 10 from each population and conduct a statistical comparison, to help make a conclusion about whether the 2 populations are different.