Five-year outcomes of moderately hypofractionated proton therapy incorporating elective pelvic nodal irradiation for high-risk prostate cancer.

Purpose: To assess the efficacy of moderately hypofractionated intensity-modulated proton therapy (IMPT) targeting the prostate/seminal vesicles and pelvic lymph nodes for high-risk (HR) or unfavorable intermediate-risk (UIR) prostate cancer (PCa) MATERIALS/METHODS: A prospective study (ClinicalTrials.gov: NCTXXX) of moderately hypofractionated IMPT accrued a target sample size of 56 patients with HR or UIR-PCa . The prostate/seminal vesicles and pelvic lymph nodes were treated simultaneously with 67.

Five-Year Prostate-Specific Membrane Antigen Positron Emission Tomography-Based Outcomes of Spot-Scanning Proton Radiation Therapy for Localized Prostate Cancer: A Single Institution Experience.

Purpose: We report 5-year oncologic outcomes of a prospective series of patients with prostate cancer treated with spot-scanning proton therapy (SSPT).

Methods And Materials: A prospective registry identified patients with prostate cancer treated with SSPT between January 2016 and December 2018. Five-year overall survival, local control, biochemical failure, regional and distant failures, and adverse events (AEs) were assessed.

Accurate patient alignment without unnecessary imaging using patient-specific 3D CT images synthesized from 2D kV images.

Background: In radiotherapy, 2D orthogonally projected kV images are used for patient alignment when 3D-on-board imaging (OBI) is unavailable. However, tumor visibility is constrained due to the projection of patient's anatomy onto a 2D plane, potentially leading to substantial setup errors. In treatment room with 3D-OBI such as cone beam CT (CBCT), the field of view (FOV) of CBCT is limited with unnecessarily high imaging dose.

Evaluation of knowledge-based planning models for male pelvic CBCT-based online adaptive radiotherapy on conventional linear accelerators.

Purpose: To assess the practicality of employing a commercial knowledge-based planning tool (RapidPlan) to generate adapted intact prostate and prostate bed volumetric modulated arc therapy (VMAT) plans on iterative cone-beam computed tomography (iCBCT) datasets.

Methods And Materials: Intact prostate and prostate bed RapidPlan models were trained utilizing planning data from 50 and 44 clinical cases, respectively. To ensure that refined models were capable of producing adequate clinical plans with a single optimization, models were tested with 50 clinical planning CT datasets by comparing dose-volume histogram (DVH) and plan quality metric (PQM) values between clinical and RapidPlan-generated plans.

Mean Oral Cavity Organ-at-Risk Dose Predicts Opioid Use and Hospitalization during Radiotherapy for Patients with Head and Neck Tumors.

Background: Approximately 75% of all head and neck cancer patients are treated with radiotherapy (RT). RT to the oral cavity results in acute and late adverse events which can be severe and detrimental to a patient's quality of life and function. The purpose of this study was to explore associations between RT dose to a defined oral cavity organ-at-risk (OAR) avoidance structure, provider- and patient-reported outcomes (PROs), opioid use, and hospitalization.

A Radiomics-Based Classifier for the Progression of Oropharyngeal Cancer Treated with Definitive Radiotherapy.

In this study, we investigated whether radiomics features from pre-treatment positron emission tomography (PET) images could be used to predict disease progression in patients with HPV-positive oropharyngeal cancer treated with definitive proton or x-ray radiotherapy. Machine learning models were built using a dataset from Mayo Clinic, Rochester, Minnesota (n = 72) and tested on a dataset from Mayo Clinic, Phoenix, Arizona (n = 22). A total of 71 clinical and radiomics features were considered.

First Report On Physician Assessment and Clinical Acceptability of Custom-Retrained Artificial Intelligence Models for Clinical Target Volume and Organs-at-Risk Auto-Delineation for Postprostatectomy Patients.

Purpose: To assess the clinical acceptability of a commercial deep-learning-based auto-segmentation (DLAS) prostate model that was retrained using institutional data for delineation of the clinical target volume (CTV) and organs-at-risk (OARs) for postprostatectomy patients, accounting for clinical and imaging protocol variations.

Methods And Materials: CTV and OARs of 109 prostate-bed patients were used to evaluate the performance of the vendor-trained model and custom retrained DLAS models using different training quantities. Two new models for OAR structures were retrained (n = 30, 60 data sets), while separate models were trained for a new CTV structure (n = 30, 60, 90 data sets), with the remaining data sets used for testing (n = 49, 19).

Initial Quality of Life and Toxicity Analysis of a Randomized Phase 3 Study of Moderately Hypofractionated Radiation Therapy With or Without Androgen Suppression for Intermediate-Risk Adenocarcinoma of the Prostate: PCG GU003.

Purpose: Our objective was to report the quality of life (QoL) analysis and toxicity in patients with intermediate-risk prostate cancer treated with or without androgen deprivation therapy (ADT) in Proton Collaborative Group (PCG) GU003.

Methods And Materials: Between 2012 and 2019, patients with intermediate-risk prostate cancer were enrolled. Patients were randomized to receive moderately hypofractionated proton beam therapy (PBT) to 70 Gy relative biologic effectiveness in 28 fractions to the prostate with or without 6 months of ADT.

Preliminary Analysis of a Phase II Trial of Stereotactic Body Radiation Therapy for Prostate Cancer With High-Risk Features After Radical Prostatectomy.

Purpose: There are limited data regarding using stereotactic body radiation therapy (SBRT) in the postprostatectomy setting. Here, we present a preliminary analysis of a prospective phase II trial that aimed to evaluate the safety and efficacy of postprostatectomy SBRT for adjuvant or early salvage therapy.

Materials And Methods: Between May 2018 and May 2020, 41 patients fulfilled inclusion criteria and were stratified into 3 groups: group I (adjuvant), prostate-specific antigen (PSA) < 0.

Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy-Part 2: Feasibility of Margin Reduction for Fractionated Radiation Treatment with Advanced Image Guidance.

Purpose: Planning target volume (PTV) expansion for post-prostatectomy radiotherapy is typically ≥5 mm. Recent clinical trials have proved the feasibility of a reduced margin of 2−3 mm for treatments on MRI-linac. We aim to study the minimum PTV margin needed using iterative cone-beam CT (iCBCT) as image guidance on conventional linacs.

Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy-Part 1: Consistent Organs at Risk Management with Advanced Image Guidance.

Purpose: Post-operative prostate cancer patients are treated with full bladder instruction and the use of an endorectal balloon (ERB). We reassessed the efficacy of this practice based on daily image guidance and dose delivery using high-quality iterative reconstructed cone-beam CT (iCBCT). Methods: Fractional dose delivery was calculated on daily iCBCT for 314 fractions from 14 post-operative prostate patients (8 with and 6 without ERB) treated with volumetric modulated radiotherapy (VMAT).

Late Toxicity of Moderately Hypofractionated Intensity-Modulated Proton Therapy Treating the Prostate and Pelvic Lymph Nodes for High-Risk Prostate Cancer.

Purpose: To evaluate late gastrointestinal (GI) and genitourinary (GU) toxicity of moderately hypofractionated intensity modulated proton therapy (IMPT) targeting the prostate and pelvic lymph nodes.

Methods And Materials: A target accrual of 56 patients with high-risk or unfavorable intermediate risk prostate cancer were enrolled into a prospective study (ClinicalTrials.gov: NCT02874014) of moderately hypofractionated IMPT.

Technical note: Investigation of dose and LET effect to rectum and bladder by using non-straight laterals in prostate cancer receiving proton therapy.

Background: Parallel-opposed lateral beams are the conventional beam arrangements in proton therapy for prostate cancer. However, when considering linear energy transfer (LET) and RBE effects, alternative beam arrangements should be investigated.

Purpose: To investigate the dose and dose averaged LET (LET ) impact of using new beam arrangements rotating beams 5°-15° posteriorly to the laterals in prostate cancer treated with pencil-beam-scanning (PBS) proton therapy.

Exploratory study of seed spots analysis to characterize dose and linear-energy-transfer effect in adverse event initialization of pencil-beam-scanning proton therapy.

Background: Both dose and linear energy transfer (LET) could play a substantial role in adverse event (AE) initialization of cancer patients treated with pencil-beam-scanning (PBS) proton therapy. However, not all the voxels within the AE regions are directly induced from the dose and LET effect. It is important to study the synergistic effect of dose and LET in AE initialization by only including a subset of voxels that are dosimetrically important.

Toxicity and outcomes after external beam irradiation for prostate cancer in patients with prior holmium laser enucleation of the prostate: Early experience.

Purpose/objectives: Holmium laser enucleation of the prostate (HoLEP) is commonly performed in patients with significant bladder outlet obstruction. However, there are few reports on the toxicity of external beam irradiation (RT) for prostate cancer in patients after prior HoLEP. In this study, we evaluate the side effects and treatment outcomes of RT after HoLEP.

A Phase II prospective study of hypofractionated proton therapy of prostate and pelvic lymph nodes: Acute effects on patient-reported quality of life.

Background: The objective of this study was to report acute changes in patient-reported quality of life (PRQOL) using the 26-item Expanded Prostate Index Composite (EPIC-26) questionnaire in a prospective study using hypofractionated intensity-modulated proton beam therapy (H-IMPT) targeting the prostate and the pelvic lymph nodes for high-risk or unfavorable intermediate-risk prostate cancer.

Methods: Fifty-five patients were enrolled. H-IMPT consisted of 45 GyE to the pelvic lymph nodes and 67.

Biologically Effective Dose and Rectal Bleeding in Definitive Proton Therapy for Prostate Cancer.

Purpose And Objectives: With increasing use of hypofractionation and extreme hypofractionation for prostate cancer, rectal dose-volume histogram (DVH) parameters that apply across dose fractionations may be helpful for treatment planning in clinical practice. We present an exploratory analysis of biologically effective rectal dose (BED) and equivalent rectal dose in 2 Gy fractions (EQD2) for rectal bleeding in patients treated with proton therapy across dose fractionations.

Materials And Methods: From 2016 to 2018, 243 patients with prostate cancer were treated with definitive proton therapy.

Empirical Relative Biological Effectiveness (RBE) for Mandible Osteoradionecrosis (ORN) in Head and Neck Cancer Patients Treated With Pencil-Beam-Scanning Proton Therapy (PBSPT): A Retrospective, Case-Matched Cohort Study.

Purpose: To retrospectively investigate empirical relative biological effectiveness (RBE) for mandible osteoradionecrosis (ORN) in head and neck (H&N) cancer patients treated with pencil-beam-scanning proton therapy (PBSPT).

Methods: We included 1,266 H&N cancer patients, of which, 931 patients were treated with volumetric-modulated arc therapy (VMAT) and 335 were treated with PBSPT. Among them, 26 VMAT and 9 PBSPT patients experienced mandible ORN (ORN group), while all others were included in the control group.

An comparison of acute toxicities and patient-reported outcomes between intensity-modulated proton therapy and volumetric-modulated arc therapy after ipsilateral radiation for head and neck cancers.

Background: Intensity-modulated proton therapy (IMPT) demonstrates superior dose distribution over volumetric-modulated arc therapy (VMAT) for sparing organs-at-risk (OARs) in ipsilateral radiotherapy. To determine a clinical benefit, assessment of patient-reported outcomes (PRO) and physician-reported toxicities alongside a dosimetric analysis is needed.

Methods: Plans were analyzed for dosimetric differences.

Proton Therapy of Prostate and Pelvic Lymph Nodes for High Risk Prostate Cancer: Acute Toxicity.

Purpose: To assess acute gastrointestinal (GI) and genitourinary (GU) toxicities of intensity-modulated proton therapy (IMPT) targeting the prostate/seminal vesicles and pelvic lymph nodes for prostate cancer.

Materials And Methods: A prospective study (ClinicalTrials.gov: NCT02874014), evaluating moderately hypofractionated IMPT for high-risk or unfavorable intermediate-risk prostate cancer, accrued a target sample size of 56 patients.