A Prospective Single-Arm Phase 2 Study of Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy for Prostate Cancer: Early Toxicity Results

Bruynzeel, A.; Tetar, S.; Oei, S.S.; Senan, Suresh; Haasbeek, Cornelis J.A.; Spoelstra, F.; Piet, Anna H.M.; Meijnen, Philip; Jagt, Marjolein A.B. Bakker van der; Fraikin, Tamara; Slotman, B.J.; Moorselaar, R. Jeroen A. van; Lagerwaard, Frank J.

doi:10.1016/j.ijrobp.2019.08.007

Cited by 145 publications

(138 citation statements)

References 23 publications

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“…Besides respiratory gating, cine-MR-based structure tracking can also be used to monitor targets that do not move with respiration, for example the prostate. First published results show that this facilitates safe administration of MR-guided ultra-hypofractionated prostate treatments, potentially enabling margin reduction while eliminating the need for fiducial or transponder implantation [32].…”

Section: Discussionmentioning

confidence: 99%

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

et al. 2020

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Purpose Magnetic resonance-guided radiotherapy (MRgRT) has recently been introduced in our institution. As MRgRT requires high patient compliance compared to conventional techniques and can be associated with prolonged treatment times, feasibility and patient tolerance were prospectively assessed using patient-reported outcome questionnaires (PRO-Q). Materials and methods Forty-three patients were enrolled in a prospective observational study and treated with MRgRT on a low-field hybrid Magnetic Resonance Linear Accelerator system (MR-Linac) between April 2018 and April 2019. For assistance in gated breath-hold delivery using cine-MRI, a video feedback system was installed. PRO-Qs consisted of questions on MR-related complaints and also assessed aspects of active patient participation. Results The most commonly treated anatomic sites were nodal metastases and liver lesions. The mean treatment time was 34 min with a mean beam-on time of 2:17 min. Gated stereotactic body radiotherapy (SBRT) was applied in 47% of all patients. Overall, patients scored MRgRT as positive or at least tolerable in the PRO-Q. Almost two thirds of patients (65%) complained about at least one item of the PRO-Q (score ≥4), mainly concerning coldness, paresthesia, and uncomfortable positioning. All patients reported high levels of satisfaction with their active role using the video feedback system in breath-hold delivery. Conclusion MRgRT was successfully implemented in our clinic and well tolerated by all patients, despite MR-related complaints and complaints about uncomfortable immobilization. Prospective clinical studies are in development for further evaluation of MRgRT and for quantification of the benefit of MR-guided on-table adaptive radiotherapy.

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Section: Discussionmentioning

confidence: 99%

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

et al. 2020

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“…To the best of our knowledge, this is the first report evaluating QoL and PROMs during 1.5T MR-guided SBRT for prostate cancer. Similarly, Bruynzeel et al [20] recently published an early toxicity report using a different MRI-guided SBRT (0.35 T MR, MRIdian system -ViewRay Inc.) in a large prostate cancer sample size. Regarding the PROMs, Bruynzeel et al [20] recorded a significant worsening of the role-functioning domain.…”

Section: Discussionmentioning

confidence: 99%

1.5T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

Alongi

Rigo

Figlia

et al. 2020

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Background Unity Elekta is a unique magnetic resonance (MR)-linac that conjugates a 1.5 Tesla MR unit with a 7 MV flattening filter free accelerator.A prospective observational study for the clinical use of Elekta Unity is currently ongoing in our department. Herein, we present our preliminary report on the feasibility, quality of life, and patient-reported outcomes measures (PROMs) for localized prostate cancer (PC) treated with stereotactic body radiotherapy (SBRT). Methods The SBRT protocol consisted of a 35 Gy schedule delivered in 5 fractions within two weeks. Toxicity and quality of life (QoL) were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v5.0, International Prostatic Symptoms Score (IPSS), ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. Results Between October 2019 and January 2020, 25 patients with localized PC were recruited. The median age was 68 years (range, 54-82); 4 were low risk, 11 favorable intermediate risk (IR) and 10 unfavorable IR. Median iPSA was 6.8 ng/ml (range, 1-19), and 9 of these patients (36%) received concurrent androgen deprivation therapy. Median prostate volume was 36 cc (range, 20-61); median baseline IPSS was 5 (range, 0-10). Median time for fraction was 53 minutes (range, 34-86); adaptive strategy with daily critical structure and target re-contouring and daily replanning (adapt to shape) was performed in all cases. No grade ≥ 3 adverse event was observed, three patients (12%) reported grade 2 acute genitourinary toxicity (urinary frequency, urinary tract pain and urinary retention), while only one patient reported mild rectal pain. No relevant deteriorations were reported in PROMs. Conclusion To the best of our knowledge, this is the first experience reporting feasibility, clinician-reported outcome measurements, and PROMs for 1.5T MR-guided adaptive SBRT for localized prostate cancer. The preliminary data collected here report optimal safety and excellent tolerability, as also confirmed by PROMs questionnaires. Moreover, the data on technical feasibility and timing of online daily adapted planning and delivery are promising. More mature data are warranted.

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“…Extreme hypofractionation with stereotactic body radiotherapy (SBRT) in prostate cancer leads to low genitourinary (GU) and gastrointestinal (GI) toxicity . Recently, MR‐guided radiotherapy (MRgRT) has become viable, resulting in even lower GU and GI toxicity . In MRgRT, a pretreatment MRI is used to delineate the clinical target volume (CTV), prior to the daily fractions of radiotherapy.…”

Section: Introductionmentioning

confidence: 99%

“…4 Recently, MR-guided radiotherapy (MRgRT) has become viable, [5][6][7] resulting in even lower GU and GI toxicity. 8 In MRgRT, a pretreatment MRI is used to delineate the clinical target volume (CTV), prior to the daily fractions of radiotherapy. At the start of each fraction, the pretreatment scan is registered to the daily fraction scan.…”

Section: Introductionmentioning

confidence: 99%

Fast contour propagation for MR‐guided prostate radiotherapy using convolutional neural networks

et al. 2020

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Purpose To quickly and automatically propagate organ contours from pretreatment to fraction images in magnetic resonance (MR)‐guided prostate external‐beam radiotherapy. Methods Five prostate cancer patients underwent 20 fractions of image‐guided external‐beam radiotherapy on a 1.5 T MR‐Linac system. For each patient, a pretreatment T2‐weighted three‐dimensional (3D) MR imaging (MRI) scan was used to delineate the clinical target volume (CTV) contours. The same scan was repeated during each fraction, with the CTV contour being manually adapted if necessary. A convolutional neural network (CNN) was trained for combined image registration and contour propagation. The network estimated the propagated contour and a deformation field between the two input images. The training set consisted of a synthetically generated ground truth of randomly deformed images and prostate segmentations. We performed a leave‐one‐out cross‐validation on the five patients and propagated the prostate segmentations from the pretreatment to the fraction scans. Three variants of the CNN, aimed at investigating supervision based on optimizing segmentation overlap, optimizing the registration, and a combination of the two were compared to results of the open‐source deformable registration software package Elastix. Results The neural networks trained on segmentation overlap or the combined objective achieved significantly better Hausdorff distances between predicted and ground truth contours than Elastix, at the much faster registration speed of 0.5 s. The CNN variant trained to optimize both the prostate overlap and deformation field, and the variant trained to only maximize the prostate overlap, produced the best propagation results. Conclusions A CNN trained on maximizing prostate overlap and minimizing registration errors provides a fast and accurate method for deformable contour propagation for prostate MR‐guided radiotherapy.

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A Prospective Single-Arm Phase 2 Study of Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy for Prostate Cancer: Early Toxicity Results

Cited by 145 publications

References 23 publications

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

1.5T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

Fast contour propagation for MR‐guided prostate radiotherapy using convolutional neural networks

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