Feasibility of quantitative relaxometry for prostate target localization and response assessment in magnetic resonance-guided online adaptive stereotactic body radiotherapy.

Purpose: Multiparametric magnetic resonance imaging (MRI) is known to provide predictors for malignancy and treatment outcome. The inclusion of these datasets in workflows for online adaptive planning remains under investigation. We demonstrate the feasibility of longitudinal relaxometry in online MR-guided adaptive stereotactic body radiotherapy (SBRT) to the prostate and dominant intra-prostatic lesion (DIL).

Commissioning and implementation of a pencil-beam algorithm with a Lorentz correction as a secondary dose calculation algorithm for an Elekta Unity 1.5T MR linear accelerator.

Purpose: To commission a beam model in ClearCalc (Radformation Inc.) for use as a secondary dose calculation algorithm and to implement its use into an adaptive workflow for an MR-linear accelerator.

Methods: A beam model was developed using commissioning data for an Elekta Unity MR-linear accelerator and entered into ClearCalc.

Depth of Hydrogel Spacer Rectal Wall Infiltration Was Not Associated With Rectal Toxicity: Results From a Randomized Prospective Trial.

Purpose: Rectal spacers have gained popularity as a dose-sparing material for prostate cancer radiation therapy (RT). However, the procedure can be associated with unintended rectal wall infiltration (RWI) of the spacer gel. We therefore classified RWI severity as a function of depth and explored its association with rectal toxicity using a data set from prostate cancer patients treated with RT on a prospective randomized clinical trial (RCT).

Reduction of Postradiation Therapy Urinary Toxicity Via Intrafractional Megavoltage-Kilovoltage Prostate Location Monitoring.

Purpose: We hypothesized that an in-house developed system using megavoltage and kilovoltage image guidance (MKIG) to ensure correct prostate positioning during stereotactic body radiation therapy (SBRT) could potentially avoid unwanted doses to nontarget tissues, leading to reduced toxicities.

Methods And Materials: We built a 3-dimensional MKIG platform that accurately tracks prostate implanted fiducials in real time and clinically translated the system to replace a commercial approach, intrafraction motion review (IMR), which only tracks fiducials in the 2-dimensional kilovoltage views. From 2017 to 2019, 150 patients with prostate cancer were treated with SBRT and monitored using MKIG.

Hypofractionated Radiation Therapy (Hypo-RT) for the Treatment of Localized Bladder Cancer.

Background: Various radiotherapeutic regimens are used in the treatment of bladder cancer.

Objective: We aimed to evaluate early toxicity and outcomes associated with hypofractionated radiation therapy (Hypo-RT), 55Gy in 20 fractions.

Material And Methods: We identified 40 patients who received definitive Hypo-RT for localized bladder cancer.

Long-term Outcomes from a Phase 1 Dose Escalation Study Using Stereotactic Body Radiotherapy for Patients with Low- or Intermediate-risk Prostate Cancer.

Background: Ultrahypofractionated stereotactic body radiation therapy (SBRT) has become a standard treatment intervention for localized prostate cancer.

Objective: To report final long-term tumor control outcomes and late gastrointestinal (GI) and genitourinary (GU) toxicities from a single-center phase 1 dose escalation study using SBRT for patients with low- or intermediate-risk prostate cancer.

Design, Setting And Participants: Between 2009 and 2012, 136 patients were enrolled and treated.

Lesion Dosimetry for [Lu]Lu-PSMA-617 Radiopharmaceutical Therapy Combined with Stereotactic Body Radiotherapy in Patients with Oligometastatic Castration-Sensitive Prostate Cancer.

A single-institution prospective pilot clinical trial was performed to demonstrate the feasibility of combining [Lu]Lu-PSMA-617 radiopharmaceutical therapy (RPT) with stereotactic body radiotherapy (SBRT) for the treatment of oligometastatic castration-sensitive prostate cancer. Six patients with 9 prostate-specific membrane antigen (PSMA)-positive oligometastases received 2 cycles of [Lu]Lu-PSMA-617 RPT followed by SBRT. After the first intravenous infusion of [Lu]Lu-PSMA-617 (7.

Identification of incidental brain tumors in prostate cancer patients via PSMA PET/CT.

Purpose: Brain metastases are rare in patients with prostate cancer and portend poor outcome. Prostate-specific membrane antigen positron emission tomography (PSMA PET)/CT scans including the brain have identified incidental tumors. We sought to identify the incidental brain tumor detection rate of PSMA PET/CT performed at initial diagnosis or in the setting of biochemical recurrence.

Assessment of Patients With Prostate Cancer and Their Understanding of the International Prostate Symptom Score Questionnaire.

Purpose: The International Prostate Symptom Score (IPSS) is a widely used tool for evaluating patient-reported lower urinary tract symptoms. In this study, we assessed patients with prostate cancer and their understanding of IPSS questions.

Methods And Materials: Consecutive patients with prostate cancer (N = 144) self-completed an online IPSS questionnaire within 1 week before their visit at our radiation oncology clinic.

Quality Metric to Assess Adequacy of Hydrogel Rectal Spacer Placement for Prostate Radiation Therapy and Association of Metric Score With Rectal Toxicity Outcomes.

Purpose: Although hydrogel spacer placement (HSP) minimizes rectal dose during prostate cancer radiation therapy, its potential benefit for modulating rectal toxicity could depend on the achieved prostate-rectal separation. We therefore developed a quality metric associated with rectal dose reduction and late rectal toxicity among patients treated with prostate stereotactic body radiation therapy (SBRT).

Methods And Materials: A quality metric consisting of prostate-rectal interspace measurements from axial T2-weighted magnetic resonance imaging simulation images was applied to 42 men enrolled in a multi-institutional phase 2 study using HSP with prostate SBRT (45 Gy in 5 fractions).

Salvage prostate brachytherapy in radiorecurrent prostate cancer: An international Delphi consensus study.

Background And Purpose: Local recurrences after previous radiotherapy (RT) are increasingly being identified in biochemically recurrent prostate cancer. Salvage prostate brachytherapy (BT) is an effective and well tolerated treatment option. We sought to generate international consensus statements on the use and preferred technical considerations for salvage prostate BT.

Quantitative longitudinal mapping of radiation-treated prostate cancer using MR fingerprinting with radial acquisition and subspace reconstruction.

MR fingerprinting (MRF) enables fast multiparametric quantitative imaging with a single acquisition and has been shown to improve diagnosis of prostate cancer. However, most prostate MRF studies were performed with spiral acquisitions that are sensitive to B0 inhomogeneities and consequent blurring. In this work, a radial MRF acquisition with a novel subspace reconstruction technique was developed to enable fast T1/T2 mapping in the prostate in under 4 min.

Deep learning-based dominant index lesion segmentation for MR-guided radiation therapy of prostate cancer.

Background: Dose escalation radiotherapy enables increased control of prostate cancer (PCa) but requires segmentation of dominant index lesions (DIL). This motivates the development of automated methods for fast, accurate, and consistent segmentation of PCa DIL.

Purpose: To construct and validate a model for deep-learning-based automatic segmentation of PCa DIL defined by Gleason score (GS) ≥3+4 from MR images applied to MR-guided radiation therapy.

A Multicenter Prospective Trial of Electronic Skin Surface Brachytherapy for Keratinocyte Carcinoma: Early Cosmesis, Quality of Life, and Adverse Events.

Purpose: Keratinocyte carcinomas are amenable to many treatments, including radiation therapy (RT). Electronic skin surface brachytherapy (ESSB) enables the precise delivery of radiation without radioisotopes. In this prospective multicenter clinical trial, we characterized early outcomes of ESSB prospectively through both patient- and clinician-reported measures.

SBRT focal dose intensification using an MR-Linac adaptive planning for intermediate-risk prostate cancer: An analysis of the dosimetric impact of intra-fractional organ changes.

Introduction: Using an magnetic resonance linear accelerator (MR-Linac) may improve the precision of visible tumor boosting with ultra-hypofractionation by accounting for daily positional changes in the target and organs at risk (OAR).

Patients And Methods: Fifteen patients with prostate cancer and an MR-detected dominant lesion were treated on the MR-Linac with stereotactic body radiation (SBRT) to 40 Gy in 5 fractions, boosting the gross tumor volume (GTV) to 45 Gy with daily adaptive planning. Imaging was acquired again after initial planning (verification scan), and immediately after treatment (post-treatment scan).

Consensus Quality Measures and Dose Constraints for Prostate Cancer From the Veterans Affairs Radiation Oncology Quality Surveillance Program and American Society for Radiation Oncology Expert Panel.

Purpose: There are no agreed upon measures to comprehensively determine the quality of radiation oncology (RO) care delivered for prostate cancer. Consequently, it is difficult to assess the implementation of scientific advances and adherence to best practices in routine clinical practice. To address this need, the US Department of Veterans Affairs (VA) National Radiation Oncology Program established the VA Radiation Oncology Quality Surveillance (VA ROQS) Program to develop clinical quality measures to assess the quality of RO care delivered to Veterans with cancer.

Radiation therapy for anorectal cancer in patients with a history of prostate radiation therapy.

Introduction: Radiation therapy (RT) for anorectal cancer after prior prostate cancer RT is usually avoided due to concern for complications. Data on this topic is scarce. Our aim was to evaluate tolerability, toxicity, and clinical outcomes associated with a second course of pelvic radiation in men with anorectal cancers previously treated with RT for prostate cancer.

Failure Patterns by PSMA PET for Recurrent Prostate Cancer after Prostatectomy and Salvage Radiation.

Objective: To characterize patterns of failure using prostate-specific membrane antigen positron emission tomography (PSMA PET) after radical prostatectomy (RP) and salvage radiotherapy (SRT).

Methods: Patients with rising PSA post-RP+SRT underwent Ga-HBED-iPSMA PET/CT on a single-arm, prospective imaging trial (NCT03204123). Scans were centrally reviewed with pattern-of-failure analysis by involved site.

Combined brachytherapy and ultra-hypofractionated radiotherapy for intermediate-risk prostate cancer: Comparison of toxicity outcomes using a high-dose-rate (HDR) versus low-dose-rate (LDR) brachytherapy boost.

Purpose/objective: To compare toxicity profiles of low-dose rate (LDR) and high-dose rate (HDR) brachytherapy boost combined with ultra-hypofractionated external beam radiation therapy (UH-EBRT).

Materials/methods: 99 patients with intermediate-risk prostate cancer underwent an HDR (n = 59) or LDR (n = 40) boost combined with UH-EBRT (5 Gy x 5) . HDR (Ir-192) was delivered a single dose (15 Gy) and LDR (Pd-103) prescription dose was 100 Gy.

Implementation Strategies to Increase Clinical Trial Enrollment in a Community-Academic Partnership and Impact on Hispanic Representation: An Interrupted Time Series Analysis.

Purpose: Community-academic partnerships have the potential to improve access to clinical trials for under-represented minority patients who more often receive cancer treatment in community settings. In 2017, the Memorial Sloan Kettering (MSK) Cancer Center began opening investigator-initiated clinical trials in radiation oncology in targeted community-based partner sites with a high potential to improve diverse population accrual. This study evaluates the effectiveness of a set of implementation strategies for increasing overall community-based enrollment and the resulting proportional enrollment of Hispanic patients on trials on the basis of availability in community-based partner sites.

Local Failure after Prostate SBRT Predominantly Occurs in the PI-RADS 4 or 5 Dominant Intraprostatic Lesion.

Background: A positive post-treatment prostate biopsy following definitive radiotherapy carries significant prognostic implications.

Objective: To determine whether local recurrences after prostate stereotactic body radiation therapy (SBRT) are associated with the presence of and occur more commonly within the region of a PI-RADS 4 or 5 dominant intra-prostatic lesion (DIL) identified on pre-treatment multi-parametric magnetic resonance imaging (MRI).

Design, Setting, And Participants: 247 patients with localized prostate cancer treated with SBRT at our institution from 2009-2018 underwent post-treatment biopsies (median time to biopsy: 2.