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Prostate cancer IGRT - Top 30 Publications

Safety and feasibility of prostate stereotactic ablative radiotherapy using multi-modality imaging and flattening filter free.

To investigate feasibility and safety of SABR in the management of prostate cancer while employing MR/CT fusion for delineation, fiducial markers seeds for positioning and Varian Rapidarc with FFF delivery.

Intrafractional Tracking Accuracy of a Transperineal Ultrasound Image Guidance System for Prostate Radiotherapy.

The aim of this study is to evaluate the tracking accuracy of a commercial ultrasound system under relevant treatment conditions and demonstrate its clinical utility for detecting significant treatment deviations arising from inadvertent intrafractional target motion.

Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients.

The optimal field size of salvage radiotherapy (SRT) for biochemical recurrence, particularly for patients with high-risk prostate cancer, remains undefined. This retrospective analysis was performed to investigate oncological outcomes as well as treatment-related toxicity following salvage intensity-modulated radiotherapy (IMRT) to the whole pelvis and to compare the results with other studies implementing a small field size of the prostate bed.

Long-term Outcomes of a Dose-reduction Trial to Decrease Late Gastrointestinal Toxicity in Patients with Prostate Cancer Receiving Soft Tissue-matched Image-guided Intensity-modulated Radiotherapy.

We experienced an unexpected high incidence of gastrointestinal (GI) toxicity in patients undergoing image-guided intensity-modulated radiotherapy (IG-IMRT) using helical tomotherapy in our initial 2.2 Gy/fraction schedule for prostate cancer; hence, a dose-reduction trial from 2.2 Gy to 2 Gy/fraction was conducted using modified planning target volume (PTV) contouring.

Use of hydrogel spacer for improved rectal dose-sparing in patients undergoing radical radiotherapy for localized prostate cancer: First Canadian experience.

We describe the initial experience using a hydrogel spacer (SpaceOAR) to separate the prostate-rectum interspace in patients planned to undergo radical hypofractionated, image-guided, intensity-modulated radiotherapy (IG-IMRT). We depict and discuss the impact of SpaceOAR in the context of hypofractionated IG-IMRT, and the particular considerations for its applications in the Canadian setting.

Curative Radiation Therapy at Time of Progression Under Active Surveillance Compared With Up-Front Radical Radiation Therapy for Prostate Cancer.

To describe and compare outcomes in men with initially presumed indolent prostate cancer receiving definitive radiation therapy after active surveillance (AS) versus those in a risk-matched cohort undergoing up-front radiation therapy.

Intraprostatic Fiducials Compared with Bony Anatomy and Skin Marks for Image-Guided Radiation Therapy of Prostate Cancer.

Purpose Prostate motion occurs during radiotherapy for localized prostate cancer. We evaluated the input of intraprostatic fiducials for image-guided radiation therapy and compared it with bony anatomy and skin marks. Methods Eleven patients were implanted with three fiducial markers in the prostate. Daily sets of orthogonal kV-kV images were compared with digitally reconstructed radiography. Data were recorded for skin marks, bony anatomy, and fiducial markers. The variations were analyzed along three principal axes (left-right: LR, superoinferior: SI, and anteroposterior: AP). Results A total of 2,417 measures were recorded over 38 fractions of radiotherapy (76 Gy). Fiducial marker movements from bony anatomy were ≤ 5 mm for 84.2% (confidence interval: CI 95%±1.5), 91.3% (CI 95%±1.1), and 99.5% (CI 95%±0.4) of the measures along the AP, SI, and LR axes, respectively. Ninety-five percent of the shifts between a fiducial marker and the bony anatomy were < 8 mm in the AP and SI axes, and < 3 mm in the LR axis. Fiducial marker movements from skin marks were ≤ 5 mm for 64.8% (CI 95%±1.9), 79.2% (CI 95%±1.6), and 87.2% (CI 95%±1.3) of the measures along the AP, SI, and LR axes, respectively. Bony anatomy movements from skin marks were ≤ 5 mm for 84% (CI 95%±1.4), 92% (CI 95%±1.1), and 87% (CI 95%±1.3) of the measurements along the AP, SI, and LR axes, respectively. Conclusion Using fiducial markers provides better accuracy of repositioning of the prostate than using bony anatomy and skin marks for image-guided radiotherapy of prostate cancer.

Prospective medical analysis of radiation therapist image repositioning during image-guided radiotherapy.

Radiation oncologists are responsible for deciding which day-to-day variations are acceptable or not in the treatment setup. However, properly qualified and trained radiation therapists might be capable to perform image registration. We evaluated in our centre the capability and accuracy of radiation therapists to validate positioning images in a prospective study.

Oligometastases in prostate cancer : Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT.

Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here.

Hypofractionated radiotherapy for prostate cancer in the postoperative setting: What is the evidence so far?

Postoperative external beam radiation therapy (EBRT) is a validated treatment option in the adjuvant setting for prostate cancer patients with aggressive pathological features following radical prostatectomy (RP) or as salvage modality in patients with biochemical recurrence after RP. Contemporary randomized phase III trials have provided evidence for using hypofractionation in the definitive treatment setting as an alternative to standard fractionated regimens. Biomathematical modeling for prostate cancer fractionated EBRT associated with widely available refined treatment delivery techniques such as volumetric modulated-arc therapy with image-guided RT may improve the therapeutic ratio. Nevertheless, the role of hypofractionation in the postoperative setting still remains investigational. In this systematic review of the literature we reviewed the role of hypofractionation for postoperative EBRT in the adjuvant or salvage setting in prostate cancer patients previously treated by RP. A favorable acute toxicity profile with, at least, as good biochemical control rates with hypofractionation has been suggested. And yet conflicting results have been reported concerning long-term genitourinary late toxicity. Prospective studies are eagerly awaited to assess the role of hypofractionation in the postoperative setting.

Absorbable Hydrogel Spacer Use in Prostate Radiotherapy: A Comprehensive Review of Phase 3 Clinical Trial Published Data.

To provide an update on SpaceOAR® System, a FDA approved hydrogel indicated to create distance between the prostate and rectum which has been studied in phase 2 and 3 clinical trials. Here we review and summarize these clinical results including: the safety of prostate-rectum spacer application technique, the implant quality and resulting rectal dose reduction, acute and long term rectal, urinary and sexual toxicity as well as patient reported outcomes.

Commissioning of the world's first compact pencil-beam scanning proton therapy system.

This paper summarizes clinical commissioning of the world's first commercial, clinically utilized installation of a compact, image-guided, pencil-beam scanning, intensity-modulated proton therapy system, the IBA Proteus® ONE, at the Willis-Knighton Cancer Center (WKCC) in Shreveport, LA. The Proteus® ONE is a single-room, compact-gantry system employing a cyclotron-generated proton beam with image guidance via cone-beam CT as well as stereoscopic orthogonal and oblique planar kV imaging. Coupling 220° of gantry rotation with a 6D robotic couch capable of in plane patient rotations of over 180° degrees allows for 360° of treatment access. Along with general machine characterization, system commissioning required: (a) characterization and calibration of the proton beam, (b) treatment planning system commissioning including CT-to-density curve determination, (c) image guidance system commissioning, and (d) safety verification (interlocks and radiation survey). System readiness for patient treatment was validated by irradiating calibration TLDs as well as prostate, head, and lung phantoms from the Imaging and Radiation Oncology Core (IROC), Houston. These results confirmed safe and accurate machine functionality suitable for patient treatment. WKCC also successfully completed an on-site dosimetry review by an independent team of IROC physicists that corroborated accurate Proteus® ONE dosimetry.

Iodine-125 seed implantation for synchronous pancreatic metastases from hepatocellular carcinoma: A case report and literature review.

The image-guided iodine-125 seed implantation has been widely used for a variety of tumors, including prostatic cancer, pulmonary cancer, hepatocellular carcinoma and pancreatic cancer. However, the clinical value of iodine-125 seed implantation for the treatment of pancreatic metastasis from hepatocellular carcinoma has not been reported. We presented the first case with ultrasound-guided iodine-125 seed implantation for this disease.

Effect of imaging frequency on PTV margins and geographical miss during image guided radiation therapy for prostate cancer.

The relationship between frequency of imaging during image guided radiation therapy (IGRT) and planning target volume (PTV) margin remains unclear. This issue is of practical significance given resource and time intensive nature of IGRT. The purpose of this study was to evaluate PTV margins with predefined and commonly used less-than-daily IGRT schedules using data obtained from patients treated with daily IGRT for prostate cancer.

The Transcriptional Landscape of Radiation-Treated Human Prostate Cancer: Analysis of a Prospective Tissue Cohort.

The resistance of prostate cancer to radiation therapy (RT) is a significant clinical issue and still largely unable to be guided by patient-specific molecular characteristics. The present study describes the gene expression changes induced in response to RT in human prostate tissue obtained from a prospective tissue acquisition study designed for radiobiology research.

68Ga-PSMA 11 ligand PET imaging in patients with biochemical recurrence after radical prostatectomy - diagnostic performance and impact on therapeutic decision-making.

To evaluate the diagnostic performance of [68Ga]Ga-PSMAHBED-CC conjugate 11 positron emission tomography (PSMA-PET) in the early detection of metastases in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) for clinically non-metastatic prostate cancer, to compare it to CT/MRI alone and to assess its impact on further therapeutic decisions.

Image Guided Radiation Therapy Strategies for Pelvic Lymph Node Irradiation in High-Risk Prostate Cancer: Motion and Margins.

To quantify the relative motion of the pelvic lymph nodes (LNs), seminal vesicles (SV) and prostate and define indicative margins for image-guided radiotherapy based on bony anatomy or prostate correction strategies for a 3 or 6 degrees-of-freedom couch.

A Monte-Carlo study to assess the effect of 1.5 T magnetic fields on the overall robustness of pencil-beam scanning proton radiotherapy plans for prostate cancer.

Combining magnetic-resonance imaging (MRI) and proton therapy (PT) using pencil-beam scanning (PBS) may improve image-guided radiotherapy. We aimed at assessing the impact of a magnetic field on PBS-PT plan quality and robustness. Specifically, the robustness against anatomical changes and positioning errors in an MRI-guided scenario with a 30 cm radius 1.5 T magnetic field was studied for prostate PT. Five prostate cancer patients with three consecutive CT images (CT1-3) were considered. Single-field uniform dose PBS-PT plans were generated on the segmented CT1 with Monte-Carlo-based treatment planning software for inverse optimization. Plans were optimized at 90° gantry angle without B-field (no B), with  ±1.5 T B-field (B and minus B), as well as at 81° gantry angle and  +1.5 T (B G81). Plans were re-calculated on aligned CT2 and CT3 to study the impact of anatomical changes. Dose distributions were compared in terms of changes in DVH parameters, proton range and gamma-index pass-rates. To assess the impact of positioning errors, DVH parameters were compared for  ±5 mm CT1 patient shifts in anterior-posterior (AP) and left-right (LR) direction. Proton beam deflection considerably reduced robustness against inter-fractional changes for the B scenario. Range agreement, gamma-index pass-rates and PTV V95% were significantly lower compared to no B. Improved robustness was obtained for minus B and B G81, the latter showing only minor differences to no B. The magnetic field introduced slight dosimetric changes under LR shifts. The impact of AP shifts was considerably larger, and equivalent for scenarios with and without B-field. Results suggest that robustness equivalent to PT without magnetic field can be achieved by adaptation of the treatment parameters, such as B-field orientation (minus B) with respect to the patient and/or gantry angle (B G81). MRI-guided PT for prostate cancer might thus be implemented without compromising robustness compared to state-of-the-art CT-guided PT.

Radiation therapy of locally advanced prostate cancer.

The risk classification for localized prostate cancer is based on the groups "low", "intermediate", and "high-risk" prostate cancer. Following this established risk group definition, locally advanced prostate cancer (cT3/4N0M0) has to be classified as "high-risk" prostate cancer. Radical prostatectomy or high-dose radiotherapy, which is combined with androgen deprivation, are the only curative standard treatments for locally advanced prostate cancer. Particularly adequate radiation doses, modern radiotherapy techniques like IMRT/IGRT, as well as long-term androgen suppression are essential for an optimal treatment outcome. In combination with definitive radiotherapy, androgen deprivation therapy should be started neoadjuvant/simultaneous to radiotherapy and is recommended to be continued after radiotherapy. Previous data suggest that 2‑year long-term androgen deprivation in this setting may not be inferior to 3‑year long-term androgen deprivation in high-risk patients. An additional radiation therapy of the lymphatic pathways in men with cN0 locally advanced/high-risk prostate cancer is still a matter of research. Ongoing trials may define selected subgroups with a suggested benefit at its best.

Long-term Tumor Control and Late Toxicity in Patients with Prostate Cancer Receiving Hypofractionated (2.2 Gy) Soft-tissue-matched Image-guided Intensity-modulated Radiotherapy.

We report the long-term tumor control and toxicity outcomes of patients undergoing hypofractionated (2.2 Gy) image-guided intensity-modulated radiotherapy (IG-IMRT) using tomotherapy for clinically localized prostate cancer.

Interfractional Rectal Displacement Requiring Repeated Precaution Did Not Correlate to Biochemical Control and Rectal Toxicity in Patients with Prostate Cancer Treated with Image-guided Intensity-modulated Radiation Therapy.

To investigate the correlation between frequency of action level of interfractional rectal displacement requiring repeated precaution in patients with prostate cancer and late toxicity from image-guided intensity-modulated radiation therapy (IG-IMRT) using helical tomotherapy.

Intrafraction monitoring of prostate motion during radiotherapy using the Clarity® Autoscan Transperineal Ultrasound (TPUS) system.

Implementation of the Clarity® Autoscan (Elekta) Transperineal Ultrasound (TPUS) system in Bristol is the first of its kind in the UK and we have already shown its utility in interfractional Image Guided Radiotherapy (IGRT).14 This study establishes the extent of intrafraction prostate motion as measured by Clarity and explores the potential benefits of TPUS for intrafraction monitoring.

Local Protocol Variations for Image Guided Radiation Therapy in the Multicenter Dutch Hypofractionation (HYPRO) Trial: Impact of Rectal Balloon and MRI Delineation on Anorectal Dose and Gastrointestinal Toxicity Levels.

The phase 3 HYpofractionated irradiation for PROstate cancer (HYPRO) trial randomized patients with intermediate- to high-risk localized prostate cancer to conventionally fractionated (78 Gy in 39 fractions) or hypofractionated (64.6 Gy in 19 fractions) radiation therapy. Differences in techniques and treatment protocols were present between participating centers. This study aimed to compare dose parameters and patient-reported gastrointestinal symptoms between these centers.

A Monte-Carlo study to assess the effect of 1.5T magnetic fields on the overall robustness of pencil-beam scanning proton radiotherapy plans for prostate cancer.

Combining magnetic-resonance imaging (MRI) and proton therapy (PT) using pencil-beam scanning (PBS) may improve image-guided radiotherapy. We aimed at assessing the impact of a magnetic field on PBS-PT plan quality and robustness. Specifically, the robustness against anatomical changes and positioning errors in an MRI-guided scenario with a 30 cm radius 1.5 T magnetic field was studied for prostate PT.&#13; Five prostate cancer patients with three consecutive CT images (CT1-3) were considered. Single-field uniform dose PBS-PT plans were generated on the segmented CT1 with Monte-Carlo-based treatment planning software for inverse optimization. Plans were optimized at 90° gantry angle without B-field (no B), with ±1.5 T B-field (B and minus B), as well as at 81° gantry angle and +1.5 T (B G81). Plans were re-calculated on aligned CT2 and CT3 to study the impact of anatomical changes. Dose distributions were compared in terms of changes in DVH parameters, proton range and gamma-index pass-rates. To assess the impact of positioning errors, DVH parameters were compared for ±5 mm CT1 patient shifts in anterior-posterior (AP) and left-right (LR) direction.&#13; Proton beam deflection considerably reduced robustness against inter-fractional changes for the B scenario. Range agreement, gamma-index pass-rates and PTV V95% were significantly lower compared to no B. Improved robustness was obtained for minus B and B G81, the latter showing only minor differences to no B. The magnetic field introduced slight dosimetric changes under LR shifts. The impact of AP shifts was considerably larger, and equivalent for scenarios with and without B-field.&#13; Results suggest that robustness equivalent to PT without magnetic field can be achieved by adaptation of the treatment parameters, such as B-field orientation (minus B) with respect to the patient and/or gantry angle (B G81). MRI-guided PT for prostate cancer might thus be implemented without compromising robustness compared to state-of-the-art CT-guided PT.

Postoperative radiotherapy for prostate cancer: the sooner the better and potential to reduce toxicity even further.

To evaluate biochemical relapse-free survival (bRFS), overall survival (OS), late rectal and bladder toxicities in a retrospective single institution series, also applying an in-house software for biological dose calculation.

Stereotactic body radiotherapy for primary renal cell carcinoma and adrenal metastases.

The incidence of renal cell carcinoma (RCC) and metastatic adrenal lesions continues to rise and present evolving complexities in terms of management. Technical challenges in treatment delivery are compounded by the setting of an ageing patient population with multiple medical co-morbidities. While the standard of care treatment for both primary RCC and oligometastatic adrenal lesions has typically been surgery, a number of patients may be medically or surgically inoperable, and for whom alternative options require consideration. Additionally, in metastatic disease, surgery presents an invasive option, sometimes with unacceptable risks of perioperative morbidity and therefore is considered a less desirable option to some. Stereotactic body radiotherapy (SBRT) is an established radiotherapy technique that is rapidly being incorporated into many radiotherapy departments, particu-larly with the increasing availability and capabilities of modern linear accelerators to deliver precise image guided treatment. There are considerable advantages of SBRT including its ability to provide a non-invasive ablative treatment with very few treatment sessions, with emerging evidence showing promising rates of local control (LC) and low associated mor-bidity. This review details the use of SBRT for primary RCC as well as adrenal metastases, focusing on issues including patient selection, technical considerations, and patient out-comes. Furthermore, this review explores some recent insights into the radiobiology of RCC, the immunomodulatory effects of SBRT, and the use of systemic agents with SBRT.

Emerging technologies in stereotactic body radiotherapy.

Stereotactic body radiation therapy (SBRT) stems from the initial developments of intra-cranial stereotactic radiosurgery (SRS). Despite similarity in their names and clinical goals of delivering a sufficiently high tumoricidal dose, maximal sparing of the surrounding normal tissues and a short treatment course, SBRT technologies have transformed from the early days of body frame-based treatments with X-ray verification to primarily image-guided procedures with cone-beam CT or stereoscopic X-ray systems and non-rigid body immo-bilization. As a result of the incorporation of image-guidance systems and multi-leaf col-limators into mainstream linac systems, and treatment planning systems that have also evolved to allow for routine dose calculations to permit intensity modulated radiotherapy and volumetric modulated arc therapy (VMAT), SBRT has disseminated rapidly in the community to manage many disease sites that include oligometastases, spine lesions, lung, prostate, liver, renal cell, pelvic tumors, and head and neck tumors etc. In this article, we review the physical principles and paradigms that led to the widespread adoption of SBRT practice as well as technical caveats specific to individual SBRT technologies. From the perspective of treatment delivery, we categorically described (I) C-arm linac-based SBRT technologies; (II) robotically manipulated X-band CyberKnife® technology; and (III) emerging specialized systems for SBRT that include integrated MRI-linear accelerators and the imaged-guided Gamma Knife Perfexion Icon system with expanded multi-isocenter treatments of skull-based tumors, head-and-neck and cervical-spine lesions.

Online Adaptive Radiation Therapy.

The current paradigm of radiation therapy has the treatment planned on a snapshot dataset of the patient's anatomy taken at the time of simulation. Throughout the course of treatment, this snapshot may vary from initial simulation. Although there is the ability to image patients within the treatment room with technologies such as cone beam computed tomography, the current state of the art is largely limited to rigid-body matching and not accounting for any geometric deformations in the patient's anatomy. A plan that was once attuned to the initial simulation can become suboptimal as the treatment progresses unless improved technologies are brought to bear. Adaptive radiation therapy (ART) is an evolving paradigm that seeks to address this deficiency by accounting for ongoing changes in the patient's anatomy and/or physiology during the course of treatment, affording an increasingly more accurate targeting of disease. ART relies on several components working in concert, namely in-room treatment image guidance, deformable image registration, automatic recontouring, plan evaluation and reoptimization, dose calculation, and quality assurance. Various studies have explored how a putative ART solution would improve the current state of the art of radiation therapy-some centers have even clinically implemented online adaptation. These explorations are reviewed here for a variety of sites.

Therapeutic innovations in radiation oncology for localized prostate cancer.

Intensity-modulated radiation therapy, image-guided radiation therapy with fiducial markers and prostate brachytherapy allow the delivery of dose escalation for localized prostate cancer with very low rates of long-term toxicity and sequelae. Nowadays, modern radiotherapy techniques make it possible to shorten treatment time with hypofractionation, to better protect surrounding healthy tissues and to escalate the dose even further. Advances in radiotherapy are closely linked to advances in magnetic resonance imaging (MRI) and/or PET imaging. Functional imaging makes it possible to deliver personalised pelvic nodal radiotherapy, targeting the nodal areas at higher risk of microscopic involvement. In patients with an index lesion at baseline or at failure, MR-based focal therapy or focal dose escalation with brachytherapy or stereotactic body radiation therapy is also currently investigated. MR-based adaptive radiotherapy, which makes it possible to track prostate shifts during radiation delivery, is another step forward in the integration of MR imaging in radiation delivery.

Spatial rectal dose/volume metrics predict patient-reported gastro-intestinal symptoms after radiotherapy for prostate cancer.

Gastro-intestinal (GI) toxicity after radiotherapy (RT) for prostate cancer reduces patient's quality of life. In this study, we explored associations between spatial rectal dose/volume metrics and patient-reported GI symptoms after RT for localized prostate cancer, and compared these with those of dose-surface/volume histogram (DSH/DVH) metrics.