Quantifying dose perturbations in high-risk prostate radiotherapy due to translational and rotational motion of prostate and pelvic lymph nodes.

Background: Radiotherapy of the prostate and the pelvic lymph nodes (LN) is a part of the standard of care treatment for high-risk prostate cancer. The independent translational and rotational (i.e.

Plan robustness evaluation strategies in whole-pelvic proton therapy for high-risk prostate cancer patients within a randomised clinical trial.

Background: Inter-fractional anatomical changes challenge robust delivery of whole-pelvic proton therapy for high-risk prostate cancer. Pre-treatment robust evaluation (PRE) takes uncertainties in isocenter shifts and distal beam edge in treatment plans into account. Using weekly control computed tomography scans (cCTs), the aim of this study was to evaluate the PRE strategy by comparing to an off-line during-treatment robust evaluation (DRE) while also assessing plan robustness with respect to protocol planning constraints.

Patient-reported lower limb edema after primary radiotherapy for prostate cancer.

Background: Secondary lymphedema is a known side effect to radiotherapy (RT), but limited information regarding prevalence and risk factors for lower limb edema (LLE) after curative radiotherapy in patients with prostate cancer (PCa) is available. This study provides a descriptive analysis of patient-reported LLE with analysis of risk factors in a cohort of patients with PCa treated with curative RT.

Material And Methods: A total of 302 patients with PCa with prospective registration of patient-reported LLE (EORTC QLQ-PR25 (Question 46)) were included.

Proton therapy planning and image-guidance strategies within a randomized controlled trial for high-risk prostate cancer.

The Danish Prostate Cancer Group is launching the randomized trial, PROstate PROTON Trial 1 (NCT05350475), that compares photons and protons to the prostate and pelvic lymph nodes in treatment of high-risk prostate cancer. The aim of the work described in this paper was, in preparation of this trial, to establish a strategy for conventionally fractionated proton therapy of prostate and elective pelvic lymph nodes that is feasible and robust. Proton treatments are image-guided based on gold fiducial markers and on-board imaging systems in line with current practice.

Towards range-guidance in proton therapy to detect organ motion-induced dose degradations.

Internal organ motion and deformations may cause dose degradations in proton therapy (PT) that are challenging to resolve using conventional image-guidance strategies. This study aimed to investigate the potential ofusing water-equivalent path length (WEPL) calculations to detect dose degradations occurring in PT..

3D dose reconstruction based on in vivo dosimetry for determining the dosimetric impact of geometric variations in high-dose-rate prostate brachytherapy.

Introduction: In vivo dosimetry (IVD) can be used for source tracking (ST), i.e., estimating source positions, during brachytherapy.

A phase I/II study of acute and late physician assessed and patient-reported morbidity following whole pelvic radiation in high-risk prostate cancer patients.

Background: The aim of this study was to assess acute and late morbidity measured by the physician and patient-reported outcomes (PROs) in high-risk prostate cancer (PC) patients receiving whole pelvic intensity-modulated radiotherapy (IMRT) in the setting of a national clinical trial.

Material And Methods: A total of 88 patients with adenocarcinoma of the prostate and high-risk parameters were enrolled from 2011 to 2013. All patients received 78 Gy in 39 fractions of IMRT delivering simultaneous 78 Gy to the prostate and 56 Gy to the seminal vesicles and lymph nodes.

Accuracy of an in vivo dosimetry-based source tracking method for afterloading brachytherapy - A phantom study.

Purpose: To report on the accuracy of an in vivo dosimetry (IVD)-based source tracking (ST) method for high dose rate (HDR) prostate brachytherapy (BT).

Methods: The ST was performed on a needle-by-needle basis. A least square fit of the expected to the measured dose rate was performed using the active dwell positions in the given needle.

Anatomically robust proton therapy using multiple planning computed tomography scans for locally advanced prostate cancer.

Background: Proton therapy (PT) is sensitive towards anatomical changes that may occur during a treatment course. The aim of this study was to investigate if anatomically robust PT (ARPT) plans incorporating patient-specific target motion improved target coverage while still sparing normal tissues, when applied on locally advanced prostate cancer patients where pelvic irradiation is indicated.

Material And Methods: A planning computed tomography (CT) scan used for dose calculation and two additional CTs (acquired on different days) were used to make patient-specific targets for the ARPT plans on the eight included patients.

Histopathological Features of MRI-Invisible Regions of Prostate Cancer Lesions.

Background: Previous studies have reported tumor volume underestimation with multiparametric (mp)MRI in prostate cancer diagnosis.

Purpose: To investigate why some parts of lesions are not visible on mpMRI by comparing their histopathology features to those of visible regions.

Study Type: Retrospective.

A biological modelling based comparison of radiotherapy plan robustness using photons vs protons for focal prostate boosting.

Background And Purpose: Focal tumour boosting is currently explored in radiotherapy of prostate cancer to increase tumour control. In this study we applied dose response models for both tumour control and normal tissue complications to explore the benefit of proton therapy (PT) combined with focal tumour boosting, also when accounting for inter-fractional motion.

Materials And Methods: CT scans of seven patients fused with MRI-based index volumes were used.

Time-resolved in vivo dosimetry for source tracking in brachytherapy.

Purpose: The purpose of this article is to demonstrate that brachytherapy source tracking can be realized with in vivo dosimetry. This concept could enable real-time treatment monitoring.

Methods: In vivo dosimetry was incorporated in the clinical routine during high-dose-rate prostate brachytherapy at Aarhus University Hospital.

Needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer evaluated by repeated MRI.

Purpose: To quantify needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer and propose a threshold for needle migration.

Methods And Materials: Twenty-four high-risk prostate cancer patients treated with an HDR boost of 2 × 8.5 Gy were included.

Validation of genetic predictors of late radiation-induced morbidity in prostate cancer patients.

Introduction: Normal tissue morbidity sets the dose limit for radiotherapy (RT) in cancer treatment and has importance for quality of life for cancer survivors. A previous study of prostate cancer patients treated with RT generated clinical data for radiation-induced morbidity measured by anorectal physiological methods and validated questionnaires. Other studies have identified genetic predictors associated with late radiation-induced morbidity outcome.

Beam angle evaluation to improve inter-fraction motion robustness in pelvic lymph node irradiation with proton therapy.

Background: Proton therapy dose distributions are sensitive to range variations, e.g. arising from inter-fraction organ motion.

Evaluating the influence of organ motion during photon vs. proton therapy for locally advanced prostate cancer using biological models.

Background: Proton therapy (PT) may have a normal tissue sparing potential when co-irradiating pelvic lymph nodes in patients with locally advanced prostate cancer, but may also be more sensitive towards organ motion in the pelvis. Building upon a previous study identifying motion-robust proton beam angles for pelvic irradiation, we aimed to evaluate the influence of organ motion for PT using biological models, and to compare this with contemporary photon-based RT.

Material And Methods: Eight locally advanced prostate cancer patients with a planning CT (pCT) and 8-9 repeated CT scans (rCTs) were included.

Dosimetric impact of contouring and needle reconstruction uncertainties in US-, CT- and MRI-based high-dose-rate prostate brachytherapy treatment planning.

Background And Purpose: The purpose was to evaluate the dosimetric impact of target contouring and needle reconstruction uncertainties in an US-, CT- and MRI-based HDR prostate BT treatment planning.

Material And Methods: US, CT, and MR images were acquired post-needle insertion in 22 HDR-BT procedures for 11 consecutive patients. Dose plans were simulated for an US-, CT- and MRI-based HDR-BT treatment planning procedure.

Learning curve of MRI-based planning for high-dose-rate brachytherapy for prostate cancer.

Purpose: To evaluate introduction of MRI-based high-dose-rate brachytherapy (HDRBT), including procedure times, dose-volume parameters, and perioperative morbidity.

Methods And Materials: Study included 42 high-risk prostate cancer patients enrolled in a clinical protocol, offering external beam radiotherapy + two HDRBT 8.5 Gy boosts.

Urinary bladder dose-response relationships for patient-reported genitourinary morbidity domains following prostate cancer radiotherapy.

Background And Purpose: Radiotherapy (RT) induced genitourinary (GU) morbidity is typically assessed by physicians as single symptoms or aggregated scores including symptoms from various domains. Here we apply a method to group patient-reported GU symptoms after RT for localized prostate cancer based on their interplay, and study how these relate to urinary bladder dose.

Materials And Methods: Data were taken from two Scandinavian studies (N=207/276) including men treated with external-beam RT (EBRT) to 78/70Gy (2Gy/fraction; median time-to-follow-up: 3.

Relationships between dose to the gastro-intestinal tract and patient-reported symptom domains after radiotherapy for localized prostate cancer.

Background: Gastrointestinal (GI) morbidity after radiotherapy (RT) for prostate cancer is typically addressed by studying specific single symptoms. The aim of this study was to explore the interplay between domains of patient- reported outcomes (PROs) on GI morbidity, and to what extent these are explained by RT dose to the GI tract.

Material And Methods: The study included men from two Scandinavian studies (N = 211/277) who had undergone primary external beam radiotherapy (EBRT) for localized prostate cancer to 70-78 Gy (2 Gy/fraction).

Hyperpolarized magnetic resonance spectroscopy for assessing tumor hypoxia.

Introduction: Hypoxic tumor cells are radioresistant, therefore, identification of hypoxia is crucial. Hyperpolarized magnetic resonance spectroscopy (HPMRS) allows real time measurements of the conversion of pyruvate to lactate, the final step of anaerobic energy production, and may thus allow non-invasive identification of hypoxia or treatment-induced changes in oxygenation. The aim of the study was to investigate the usefulness of HPMRS as a means to assess tumor hypoxia and its dynamics during intervention.

A method for evaluation of proton plan robustness towards inter-fractional motion applied to pelvic lymph node irradiation.

Background: The benefit of proton therapy may be jeopardized by dose deterioration caused by water equivalent path length (WEPL) variations. In this study we introduced a method to evaluate robustness of proton therapy with respect to inter-fractional motion and applied it to irradiation of the pelvic lymph nodes (LNs) from different beam angles. Patient- versus population-specific patterns in dose deterioration were explored.

The influence of a rectal ultrasound probe on the separation between prostate and rectum in high-dose-rate brachytherapy.

Purpose: The aim of this study was to compare the distance between prostate and rectum as well as rectal dose-volume histogram (DVH) parameters for high-dose-rate (HDR) prostate brachytherapy (BT) with and without a transrectal ultrasound (US) probe in place during delivery.

Methods And Materials: The study included 20 patients with high-risk prostate cancer treated consecutively with combined external beam radiotherapy (EBRT) and MRI-based HDR-BT. The MRI-based HDR-BT dose plan and prostate gland contour were transferred to the US images after rigid MRI/US coregistration, followed by delineation of the rectum on US images acquired with a transrectal US probe.

Evaluation of an application for intensity-based deformable image registration and dose accumulation in radiotherapy.

Background: Methods to accurately accumulate doses in radiotherapy (RT) are important for tumour and normal tissues being influenced by geometric uncertainties. The purpose of this study was to investigate a pre-release deformable image registration (DIR)-based dose accumulation application, in the setting of prostate RT.

Material And Methods: Initially accumulated bladder and prostate doses were assessed (based on 8-9 repeat CT scans/patient) for nine prostate cancer patients using an intensity-based DIR and dose accumulation algorithm as provided by the Dynamic Adaptive Radiation Therapy (DART) software.

Development and validation of a scoring system for late anorectal side-effects in patients treated with radiotherapy for prostate cancer.

Purpose: To develop and validate a scoring system for evaluation of long term anorectal dysfunction following radiotherapy for prostate cancer.

Materials And Methods: Patients treated for prostate cancer with radiotherapy filled in questionnaires on anorectal function and quality of life. Items for the condensed anorectal dysfunction score (RT-ARD) were identified and weighted by binomial regression analysis.