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Panettieri V, Rancati T, Onjukka E, Ebert MA, Joseph DJ, Denham JW, Steigler A, Millar JL. External Validation of a Predictive Model of Urethral Strictures for Prostate Patients Treated With HDR Brachytherapy Boost. Front Oncol 2020; 10:910. [PMID: 32596153 PMCID: PMC7300245 DOI: 10.3389/fonc.2020.00910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/11/2020] [Indexed: 12/12/2022] Open
Abstract
Purpose: For prostate cancer treatment, comparable or superior biochemical control was reported when using External-Beam-Radiotherapy (EBRT) with High-Dose-Rate-Brachytherapy (HDRB)-boost, compared to dose-escalation with EBRT alone. The conformal doses produced by HDRB could allow further beneficial prostate dose-escalation, but increase in dose is limited by normal tissue toxicity. Previous works showed correlation between urethral dose and incidence of urinary toxicity, but there is a lack of established guidelines on the dose constraints to this organ. This work aimed at fitting a Normal-Tissue-Complication-Probability model to urethral stricture data collected at one institution and validating it with an external cohort, looking at neo-adjuvant androgen deprivation as dose-modifying factor. Materials and Methods: Clinical and dosimetric data of 258 patients, with a toxicity rate of 12.8%, treated at a single institution with a variety of prescription doses, were collected to fit the Lyman–Kutcher–Burman (LKB) model using the maximum likelihood method. Due to the different fractionations, doses were converted into 2 Gy-equivalent doses (α/β = 5 Gy), and urethral stricture was used as an end-point. For validation, an external cohort of 187 patients treated as part of the TROG (Trans Tasman Radiation Oncology Group) 03.04 RADAR trial with a toxicity rate of 8.7%, was used. The goodness of fit was assessed using calibration plots. The effect of neo-adjuvant androgen deprivation (AD) was analyzed separating patients who had received it prior to treatment from those who did not receive it. Results: The obtained LKB parameters were TD50 = 116.7 Gy and m = 0.23; n was fixed to 0.3, based on numerical optimization of the likelihood. The calibration plot showed a good agreement between the observed toxicity and the probability predicted by the model, confirmed by bootstrapping. For the external validation, the calibration plot showed that the observed toxicity obtained with the RADAR patients was well-represented by the fitted LKB model parameters. When patients were stratified by the use of AD TD50 decreased when AD was not present. Conclusions: Lyman–Kutcher–Burman model parameters were fitted to the risk of urethral stricture and externally validated with an independent cohort, to provide guidance on urethral tolerance doses for patients treated with a HDRB boost. For patients that did not receive AD, model fitting provided a lower TD50 suggesting a protective effect on urethra toxicity.
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Affiliation(s)
- Vanessa Panettieri
- Alfred Health Radiation Oncology, Alfred Hospital, Melbourne, VIC, Australia.,Medical Imaging and Radiation Sciences, Monash University, Clayton, VIC, Australia
| | - Tiziana Rancati
- Prostate Cancer Program, Scientific Directorate, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Eva Onjukka
- Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Martin A Ebert
- Radiation Oncology, Sir Charles Gairdner Hospital, Perth, WA, Australia.,School of Physics, Mathematics and Computing, University of Western Australia, Perth, WA, Australia.,5D Clinics, Claremont, WA, Australia
| | - David J Joseph
- 5D Clinics, Claremont, WA, Australia.,GenesisCare, Subiaco, WA, Australia.,School of Surgery, University of Western Australia, WA, Australia
| | - James W Denham
- School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia
| | - Allison Steigler
- School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia
| | - Jeremy L Millar
- Alfred Health Radiation Oncology, Alfred Hospital, Melbourne, VIC, Australia.,Central Clinical School, Monash University, Melbourne, VIC, Australia
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Acosta O, Mylona E, Le Dain M, Voisin C, Lizee T, Rigaud B, Lafond C, Gnep K, de Crevoisier R. Multi-atlas-based segmentation of prostatic urethra from planning CT imaging to quantify dose distribution in prostate cancer radiotherapy. Radiother Oncol 2017; 125:492-499. [PMID: 29031609 DOI: 10.1016/j.radonc.2017.09.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/27/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND PURPOSE Segmentation of intra-prostatic urethra for dose assessment from planning CT may help explaining urinary toxicity in prostate cancer radiotherapy. This work sought to: i) propose an automatic method for urethra segmentation in CT, ii) compare it with previously proposed surrogate models and iii) quantify the dose received by the urethra in patients treated with IMRT. MATERIALS AND METHODS A weighted multi-atlas-based urethra segmentation method was devised from a training data set of 55 CT scans of patients receiving brachytherapy with visible urinary catheters. Leave-one-out cross validation was performed to quantify the error between the urethra segmentation and the catheter ground truth with two scores: the centerlines distance (CLD) and the percentage of centerline within a certain distance from the catheter (PWR). The segmentation method was then applied to a second test data set of 95 prostate cancer patients having received 78Gy IMRT to quantify dose to the urethra. RESULTS Mean CLD was 3.25±1.2mm for the whole urethra and 3.7±1.7mm, 2.52±1.5mm, and 3.01±1.7mm for the top, middle, and bottom thirds, respectively. In average, 53% of the segmented centerlines were within a radius<3.5mm from the centerline ground truth and 83% in a radius<5mm. The proposed method outperformed existing surrogate models. In IMRT, urethra DVH was significantly higher than prostate DVH from V74Gy to V79Gy. CONCLUSION A multi-atlas-based segmentation method was proposed enabling assessment of the dose within the prostatic urethra.
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Affiliation(s)
- Oscar Acosta
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France.
| | - Eugenia Mylona
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France
| | - Mathieu Le Dain
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France
| | - Camille Voisin
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France
| | - Thibaut Lizee
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France
| | - Bastien Rigaud
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France
| | - Carolina Lafond
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France; Centre Eugene Marquis, Département de Radiothérapie, Rennes, France
| | - Khemara Gnep
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France; Centre Eugene Marquis, Département de Radiothérapie, Rennes, France
| | - Renaud de Crevoisier
- INSERM U1099, Rennes, France; Université de Rennes 1 - Laboratoire du Traitement du Signal et de l'Image, France; Centre Eugene Marquis, Département de Radiothérapie, Rennes, France
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Yahya N, Ebert MA, House MJ, Kennedy A, Matthews J, Joseph DJ, Denham JW. Modeling Urinary Dysfunction After External Beam Radiation Therapy of the Prostate Using Bladder Dose-Surface Maps: Evidence of Spatially Variable Response of the Bladder Surface. Int J Radiat Oncol Biol Phys 2016; 97:420-426. [PMID: 28068247 DOI: 10.1016/j.ijrobp.2016.10.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 09/27/2016] [Accepted: 10/14/2016] [Indexed: 01/05/2023]
Abstract
PURPOSE We assessed the association of the spatial distribution of dose to the bladder surface, described using dose-surface maps, with the risk of urinary dysfunction. METHODS AND MATERIALS The bladder dose-surface maps of 754 participants from the TROG 03.04-RADAR trial were generated from the volumetric data by virtually cutting the bladder at the sagittal slice, intersecting the bladder center-of-mass through to the bladder posterior and projecting the dose information on a 2-dimensional plane. Pixelwise dose comparisons were performed between patients with and without symptoms (dysuria, hematuria, incontinence, and an International Prostate Symptom Score increase of ≥10 [ΔIPSS10]). The results with and without permutation-based multiple-comparison adjustments are reported. The pixelwise multivariate analysis findings (peak-event model for dysuria, hematuria, and ΔIPSS10; event-count model for incontinence), with adjustments for clinical factors, are also reported. RESULTS The associations of the spatially specific dose measures to urinary dysfunction were dependent on the presence of specific symptoms. The doses received by the anteroinferior and, to lesser extent, posterosuperior surface of the bladder had the strongest relationship with the incidence of dysuria, hematuria, and ΔIPSS10, both with and without adjustment for clinical factors. For the doses to the posteroinferior region corresponding to the area of the trigone, the only symptom with significance was incontinence. CONCLUSIONS A spatially variable response of the bladder surface to the dose was found for symptoms of urinary dysfunction. Limiting the dose extending anteriorly might help reduce the risk of urinary dysfunction.
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Affiliation(s)
- Noorazrul Yahya
- School of Health Sciences, National University of Malaysia, Kuala Lumpur, Malaysia; School of Physics, University of Western Australia, Perth, Western Australia, Australia.
| | - Martin A Ebert
- School of Physics, University of Western Australia, Perth, Western Australia, Australia; Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Michael J House
- School of Physics, University of Western Australia, Perth, Western Australia, Australia
| | - Angel Kennedy
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John Matthews
- Department of Radiation Oncology, Auckland City Hospital, Auckland, New Zealand
| | - David J Joseph
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; School of Surgery, University of Western Australia, Perth, Western Australia, Australia
| | - James W Denham
- School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia
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