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Spohn SKB, Radicioni G, Eisfelder M, Zamboglou C, Baltas D, Grosu AL, Sachpazidis I. Predictors of radiation-induced late rectal toxicity in prostate cancer treatment: a volumetric and dosimetric analysis. Front Oncol 2024; 14:1371384. [PMID: 38737910 PMCID: PMC11082346 DOI: 10.3389/fonc.2024.1371384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/08/2024] [Indexed: 05/14/2024] Open
Abstract
Introduction Prostate cancer (PCa) is a prevalent malignancy in European men, often treated with radiotherapy (RT) for localized disease. While modern RT achieves high success rates, concerns about late gastrointestinal (GI) toxicities persist. This retrospective study aims to identify predictors for late GI toxicities following definitive conventionally fractionated external beam RT (EBRT) for PCa, specifically exploring the dose to the rectal wall. Materials and methods A cohort of 96 intermediate- to high-risk PCa patients underwent EBRT between 2008 and 2016. Rectum and rectum wall contours were delineated, and 3D dose matrices were extracted. Volumetric and dosimetric indices were computed, and statistical analyses were performed to identify predictors using the Mann-Whitney U-rank test, logistic regression, and recursive feature elimination. Results In our cohort, 15 out of 96 patients experienced grade II late proctitis. Our analysis reveals distinct optimal predictors for rectum and rectum wall (RW) structures varying with α/β values (3.0 and 2.3 Gy) across prescribed doses of 68 to 76 Gy. Despite variability, RW predictors demonstrate greater consistency, notably V68Gy[%] to V74Gy[%] for α/β 3.0 Gy, and V68Gy[%] to V70Gy[%] for α/β 2.3 Gy. The model with α/β 2.3 Gy, featuring RW volume receiving 70 Gy (V70Gy[%]), stands out with a BIC value of 62.92, indicating its superior predictive effectiveness. Finally, focusing solely on the rectum structure, the V74Gy[%] emerges the best predictor for α/β 3.0 Gy, with a BIC value of 66.73. Conclusion This investigation highlights the critical role of V70Gy[%] in the rectum wall as a robust predictor for grade II late gastrointestinal (GI) toxicity following external beam radiation therapy (EBRT) for prostate cancer (PCa). Furthermore, our findings suggest that focusing on the rectum wall specifically, rather than the entire rectum, may offer improved accuracy in assessing proctitis development. A V70Gy (in EQD2 with α/β 2.3 Gy) of ≤5% and if possible ≤1% for the rectal wall should be achieved to minimize the risk of late grade II proctitis.
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Affiliation(s)
- Simon K. B. Spohn
- Department of Radiation Oncology, Medical Centre – University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
- Berta-Ottensein-Program, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gianluca Radicioni
- Department of Radiation Oncology, Medical Centre – University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
| | - Marcio Eisfelder
- Department of Radiation Oncology, Medical Centre – University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
| | - Constantinos Zamboglou
- Department of Radiation Oncology, Medical Centre – University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
- Department of Radiation Oncology, German Oncology Centre, European University Cyprus, Limassol, Cyprus
| | - Dimos Baltas
- Division of Medical Physics, Department of Radiation Oncology, Medical Centre - University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
| | - Anca-Ligia Grosu
- Department of Radiation Oncology, Medical Centre – University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
| | - Ilias Sachpazidis
- Division of Medical Physics, Department of Radiation Oncology, Medical Centre - University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany
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Rørtveit ØL, Hysing LB, Stordal AS, Pilskog S. An organ deformation model using Bayesian inference to combine population and patient-specific data. Phys Med Biol 2023; 68. [PMID: 36735964 DOI: 10.1088/1361-6560/acb8fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/03/2023] [Indexed: 02/05/2023]
Abstract
Objective.Organ deformation models have the potential to improve delivery and reduce toxicity of radiotherapy, but existing data-driven motion models are based on either patient-specific or population data. We propose to combine population and patient-specific data using a Bayesian framework. Our goal is to accurately predict individual motion patterns while using fewer scans than previous models.Approach.We have derived and evaluated two Bayesian deformation models. The models were applied retrospectively to the rectal wall from a cohort of prostate cancer patients. These patients had repeat CT scans evenly acquired throughout radiotherapy. Each model was used to create coverage probability matrices (CPMs). The spatial correlations between these estimated CPMs and the ground truth, derived from independent scans of the same patient, were calculated.Main results.Spatial correlation with ground truth were significantly higher for the Bayesian deformation models than both patient-specific and population-derived models with 1, 2 or 3 patient-specific scans as input. Statistical motion simulations indicate that this result will also hold for more than 3 scans.Significance.The improvement over previous models means that fewer scans per patient are needed to achieve accurate deformation predictions. The models have applications in robust radiotherapy planning and evaluation, among others.
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Affiliation(s)
- Øyvind Lunde Rørtveit
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway.,Department of Technology and Physics, University of Bergen, Norway
| | - Liv Bolstad Hysing
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway.,Department of Technology and Physics, University of Bergen, Norway
| | - Andreas Størksen Stordal
- NORCE Norwegian Research Centre, Bergen, Norway.,Department of Mathematics, University of Bergen, Norway
| | - Sara Pilskog
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway.,Department of Technology and Physics, University of Bergen, Norway
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Bhangoo RS, Petersen MM, Bulman GF, Vargas CE, Thorpe CS, Shen J, Wong WW, Rwigema JCM, Daniels TB, Keole SR, Schild SE, Rong Y, DeWees TA. Biologically Effective Dose and Rectal Bleeding in Definitive Proton Therapy for Prostate Cancer. Int J Part Ther 2021; 8:37-46. [PMID: 35530190 PMCID: PMC9009455 DOI: 10.14338/ijpt-21-00007.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 07/27/2021] [Indexed: 12/03/2022] Open
Abstract
Purpose and Objectives With increasing use of hypofractionation and extreme hypofractionation for prostate cancer, rectal dose-volume histogram (DVH) parameters that apply across dose fractionations may be helpful for treatment planning in clinical practice. We present an exploratory analysis of biologically effective rectal dose (BED) and equivalent rectal dose in 2 Gy fractions (EQD2) for rectal bleeding in patients treated with proton therapy across dose fractionations. Materials and Methods From 2016 to 2018, 243 patients with prostate cancer were treated with definitive proton therapy. Rectal DVH parameters were obtained from treatment plans, and rectal bleeding events were recorded. The BED and EQD2 transformations were applied to each rectal DVH parameter. Univariate analysis using logistic regression was used to determine DVH parameters that were significant predictors of grade ≥ 2 rectal bleeding. Youden index was used to determine optimum cutoffs for clinically meaningful DVH constraints. Stepwise model-selection criteria were then applied to fit a “best” multivariate logistic model for predicting Common Terminology Criteria for Adverse Events grade ≥ 2 rectal bleeding. Results Conventional fractionation, hypofractionation, and extreme hypofractionation were prescribed to 117 (48%), 84 (34%), and 42 (17.3%) patients, respectively. With a median follow-up of 20 (2.5-40) months, 10 (4.1%) patients experienced rectal bleeding. On univariate analysis, multiple rectal DVH parameters were significantly associated with rectal bleeding across BED, EQD2, and nominal doses. The BED volume receiving 55 Gy > 13.91% was found to be statistically and clinically significant. The BED volume receiving 55 Gy remained statistically significant for an association with rectal bleeding in the multivariate model (odds ratio, 9.81; 95% confidence interval, 2.4-40.5; P = .002). Conclusion In patients undergoing definitive proton therapy for prostate cancer, dose to the rectum and volume of the rectum receiving the dose were significantly associated with rectal bleeding across conventional fractionation, hypofractionation, and extreme hypofractionation when using BED and EQD2 transformations.
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Affiliation(s)
| | - Molly M. Petersen
- Department of Health Sciences Research, Mayo Clinic, Scottsdale, AZ, USA
| | | | | | | | - Jason Shen
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - William W. Wong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | | | | | - Sameer R. Keole
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | | | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Todd A. DeWees
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
- Department of Health Sciences Research, Mayo Clinic, Scottsdale, AZ, USA
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Ferini G, Pergolizzi S. A Ten-year-long Update on Radiation Proctitis Among Prostate Cancer Patients Treated With Curative External Beam Radiotherapy. In Vivo 2021; 35:1379-1391. [PMID: 33910815 DOI: 10.21873/invivo.12390] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/07/2021] [Accepted: 02/12/2021] [Indexed: 02/07/2023]
Abstract
This comprehensive synopsis summarizes the most relevant information obtained from a systematic analysis of studies of the last decade on radiation proctitis, one of the most feared radioinduced side effects among prostate cancer patients treated with curative external beam radiotherapy. The present review provides a useful support to radiation oncologists for limiting the onset or improving the treatment of radiation proctitis. This work shows that the past decade was a harbinger of significant new evidence in technological advances and technical tricks to avoid radiation proctitis, in addition to dosimetric perspectives and goals, understanding of pathogenesis, diagnostic work-up and treatment. We believe that a well-rounded knowledge of such an issue is fundamental for its appropriate management.
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Affiliation(s)
| | - Stefano Pergolizzi
- Department of Biomedical and Dental Sciences, Morphological and Functional Images, University of Messina, Messina, Italy
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