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Rectal retractor in prostate radiotherapy: pros and cons. Radiat Oncol 2022; 17:204. [PMID: 36494732 PMCID: PMC9737745 DOI: 10.1186/s13014-022-02176-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Dose escalation in prostate radiotherapy (RT) have led to improved biochemical controls and reduced the risk of distant metastases. Over the past three decades, despite technological advancements in RT planning and delivery, the rectum is a dose-limiting structure in prostate RT owing to the close anatomical proximity of the anterior rectal wall (ARW) to the prostate gland. RT-induced rectal toxicities remain a clinical challenge, limiting the prescribed dose during prostate RT. To address the spatial proximity challenge by physically increasing the distance between the posterior aspect of the prostate and the ARW, several physical devices such as endorectal balloons (ERBs), rectal hydrogel spacers, and rectal retractor (RR) have been developed. Previously, various aspects of ERBs and rectal hydrogel spacers have extensively been discussed. Over recent years, given the interest in the application of RR in prostate external beam radiotherapy (EBRT), this editorial will discuss opportunities and challenges of using RR during prostate EBRT and provide information regarding which aspects of this device need attention.
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Arefpour AM, Abbasi M, Rabi Mahdavi S, Shafieesabet M, Fadavi P. Clinical effects of rectal retractor application in prostate cancer radiotherapy. Med J Islam Repub Iran 2021; 35:69. [PMID: 34277506 PMCID: PMC8278024 DOI: 10.47176/mjiri.35.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Indexed: 11/09/2022] Open
Abstract
Background: Radiation-induced rectal toxicities remain as a major risk during prostate radiotherapy. One approach to the reduction of rectal radiation dose is to physically increase the distance between the rectal wall and prostate. Therefore, the aim of this study was to evaluate whether the application of the rectal retractor (RR) can reduce rectal dose and toxicity in prostate cancer 3-dimensional conformal radiotherapy (3D-CRT). Methods: Overall, 36 patients with localized prostate cancer were randomized into the 2 groups, 18 patients with RR in-place and 18 without RR. All patients underwent planning computed tomography (CT). Patients were treated with 70 Gy in 35 fractions of 3D-CRT. In the RR group, RR was used during cone-down 20 treatment fractions. Acute and late gastrointestinal (GI) toxicities were assessed using EORTC/RTOG scoring system weekly during radiotherapy, 3, and 12 months after treatment. Device-related events were recorded according to CTCAE version 4.0. Patient characteristics, cancer differences, and dosimetric data for the RR and non-RR groups were compared using a Man-Whitney U test for continuous variables, and Fisher exact test for categorical data. The EORTC/RTOG scores for the 2 groups were compared using Fisher exact test. A P value <0.05 was considered statistically significant. Results: A RR significantly reduced mean dose (Dmean) to the rectum as well as rectal volume receiving 50% to 95% (V50-95%) of prescribed dose. The absolute reduction of rectal Dmean was 10.3 Gy. There was no statistically significant difference in acute GI toxicity between groups during treatment or at 3 months. At 12 months, 2 patients in the RR group and 9 in the control group experienced late grade ≥ 1 GI toxicity (p=0.027). No patients in the RR group reported late grade ≥ 2 GI toxicity, whereas 3 patients in the control group experienced late grade 2 GI toxicity. In the RR group, 6 patients reported grade 1 rectal discomfort and pain according to CTCAE version 4.0. Conclusion: The application of the RR showed a significant rectum sparing effect, resulting in substantially reducing late GI toxicity.
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Affiliation(s)
- Amir Mohammad Arefpour
- Department of Radiation Oncology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mahshid Abbasi
- Department of Radiation Oncology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Seied Rabi Mahdavi
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahdiyeh Shafieesabet
- Department of Radiation Oncology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Pedram Fadavi
- Department of Radiation Oncology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Effectiveness of rectal displacement devices in managing prostate motion: a systematic review. Strahlenther Onkol 2020; 197:97-115. [DOI: 10.1007/s00066-020-01633-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022]
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Johansson S, Isacsson U, Sandin F, Turesson I. High efficacy of hypofractionated proton therapy with 4 fractions of 5 Gy as a boost to 50 Gy photon therapy for localized prostate cancer. Radiother Oncol 2019; 141:164-173. [DOI: 10.1016/j.radonc.2019.06.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 11/25/2022]
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5
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Ghaffari H, Afkhami Ardekani M, Molana SH, Haghparast M, Sanei M, Mahdavi SR, Mofid B, Rostami A. Application of rectal retractor for postprostatectomy salvage radiotherapy of prostate cancer: A case report and literature review. Clin Case Rep 2019; 7:2102-2107. [PMID: 31788259 PMCID: PMC6878068 DOI: 10.1002/ccr3.2430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/08/2019] [Accepted: 08/13/2019] [Indexed: 11/06/2022] Open
Abstract
Using a rectal retractor (RR) during salvage radiotherapy after radical prostatectomy is a promising approach for reducing dose to the rectum. The patient well tolerated the daily RR insertion. This area of research encourages researchers for a comprehensive evaluation of the role of the RR in postprostatectomy radiotherapy.
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Affiliation(s)
- Hamed Ghaffari
- Department of Medical PhysicsSchool of MedicineIran University of Medical SciencesTehranIran
| | - Mahdieh Afkhami Ardekani
- Department of RadiologyFaculty of Para‐MedicineHormozgan University of Medical SciencesBandare‐AbbasIran
| | - Seyed Hadi Molana
- Department of Radiation OncologySchool of MedicineAJA University of Medical SciencesTehranIran
| | - Mohammad Haghparast
- Department of Medical PhysicsSchool of MedicineIran University of Medical SciencesTehranIran
- Department of RadiologyFaculty of Para‐MedicineHormozgan University of Medical SciencesBandare‐AbbasIran
| | - Mastaneh Sanei
- Department of Radiation OncologySchool of MedicineIran University of Medical SciencesTehranIran
| | - Seied Rabi Mahdavi
- Department of Medical PhysicsSchool of MedicineIran University of Medical SciencesTehranIran
| | - Bahram Mofid
- Department of Radiation OncologyShohada‐e‐Tajrish Medical CenterShahid Beheshti University of Medical SciencesTehranIran
| | - Aram Rostami
- Department of Medical PhysicsSchool of MedicineIran University of Medical SciencesTehranIran
- Department of Medical PhysicsRoshana Cancer InstituteTehranIran
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Afkhami Ardekani M, Ghaffari H. Optimization of prostate brachytherapy techniques with polyethylene glycol-based hydrogel spacers: A systematic review. Brachytherapy 2019; 19:13-23. [PMID: 31542390 DOI: 10.1016/j.brachy.2019.08.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/01/2019] [Accepted: 08/21/2019] [Indexed: 01/07/2023]
Abstract
PURPOSE The objective of this overview was to critically evaluate the effect of polyethylene glycol (PEG)-based hydrogel spacers during prostate brachytherapy with regard to dosimetric and clinical benefits, as well as procedure-related toxicity. METHODS AND MATERIALS A systematic search in the PubMed database was performed. RESULTS A total of 12 studies, involving 615 patients with PEG hydrogel injection, were included. Overall, patients well tolerated the implantation of PEG hydrogel spacers with an excellent safety profile. However, although there were some procedure-related complications, rates of these complications were very rare. Toxicities related to the spacer were limited to Grade 1 rectal discomfort and pain (9/615 patients), Grade 2 rectal ulceration (1 in 615 patients), perineal abscess (1 in 615 patients), and bacterial prostatitis (2/615 patients) according to Common Terminology Criteria for Adverse Events v4.0 grading scheme. The application of PEG hydrogel spacers significantly reduced radiation doses to the rectum during prostate brachytherapy in the different setting. Although there was no prospective randomized clinical trial, retrospective studies showed that reducing rectal doses by the implantation of PEG hydrogel may result in an improvement in rectal toxicity. CONCLUSIONS The insertion of hydrogel spacers is safe, resulting in a significant decrease in rectal doses. This may lead to a reduction in rectal or gastrointestinal toxicity. Prospective randomized clinical trials are warranted to confirm the clinical impact of rectal dosimetric improvements.
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Affiliation(s)
- Mahdieh Afkhami Ardekani
- Department of Radiology, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandar-Abbas, Iran
| | - Hamed Ghaffari
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Rectal retractor application during image-guided dose-escalated prostate radiotherapy. Strahlenther Onkol 2019; 195:923-933. [PMID: 30824942 DOI: 10.1007/s00066-019-01445-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 02/08/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To investigate efficacy of a rectal retractor (RR) on rectal dose during image-guided dose-escalated prostate three-dimensional conformal radiotherapy (3DCRT). PATIENTS AND METHODS In all, 21 patients with localized prostate cancer were treated with a RR for 3DCRT in 40 × 2 Gy. Patient underwent two scans for radiotherapy planning, without and with RR. RR was used for the first half of the treatment sessions. Two plans were created for each patient to compare the effect of RR on rectal doses. PTW-31014 Pinpoint chamber embedded within RR was used for in vivo dosimetry in 6 of 21 patients. The patient tolerance and acute rectal toxicity were surveyed during radiotherapy using Common Terminology Criteria for Adverse Events (CTCAE) v.4.0. RESULTS Patients tolerated the RR well during 20 fractions with mild degree of anal irritation. Using a RR significantly reduced the rectal wall (RW), anterior RW and posterior RW dose-volume parameters. The average RW Dmean was 29.4 and 43.0 Gy for plans with and without RR, respectively. The mean discrepancy between the measured dose and planned dose was -3.8% (±4.9%). Grade 1 diarrhea, rectal urgency and proctitis occurred in 4, 2 and 3 cases, respectively. There were no grade ≥2 acute rectal toxicities during the treatment. CONCLUSION Rectal retraction resulted in a significant reduction of rectal doses with a safe toxicity profile, which may reduce rectal toxicity. Dosimeter inserted into the RR providing a practical method for in vivo dosimetric verification. Further prospective clinical studies will be necessary to demonstrate the clinical advantage of RR.
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Dubouloz A, Rouzaud M, Tsvang L, Verbakel W, Björkqvist M, Linthout N, Lencart J, Pérez-Moreno JM, Ozen Z, Escude L, Zilli T, Miralbell R. Urethra-sparing stereotactic body radiotherapy for prostate cancer: how much can the rectal wall dose be reduced with or without an endorectal balloon? Radiat Oncol 2018; 13:114. [PMID: 29921291 PMCID: PMC6008922 DOI: 10.1186/s13014-018-1059-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/13/2018] [Indexed: 11/20/2022] Open
Abstract
Background This is a dosimetric comparative study intended to establish appropriate low-to-intermediate dose-constraints for the rectal wall (Rwall) in the context of a randomized phase-II trial on urethra-sparing stereotactic body radiotherapy (SBRT) for prostate cancer. The effect of plan optimization on low-to-intermediate Rwall dose and the potential benefit of an endorectal balloon (ERB) are investigated. Methods Ten prostate cancer patients, simulated with and without an ERB, were planned to receive 36.25Gy (7.25Gyx5) to the planning treatment volume (PTV) and 32.5Gy to the urethral planning risk volume (uPRV). Reference plans with and without the ERB, optimized with respect to PTV and uPRV coverage objectives and the organs at risk dose constraints, were further optimized using a standardized stepwise approach to push down dose constraints to the Rwall in the low to intermediate range in five sequential steps to obtain paired plans with and without ERB (Vm1 to Vm5). Homogeneity index for the PTV and the uPRV, and the Dice similarity coefficient (DSC) for the PTV were analyzed. Dosimetric parameters for Rwall including the median dose and the dose received by 10 to 60% of the Rwall, bladder wall (Bwall) and femoral heads (FHeads) were compared. The monitor units (MU) per plan were recorded. Results Vm4 reduced by half D30%, D40%, D50%, and Dmed for Rwall and decreased by a third D60% while HIPTV, HIuPRV and DSC remained stable with and without ERB compared to Vmref. HIPTV worsened at Vm5 both with and without ERB. No statistical differences were observed between paired plans on Rwall, Bwall except a higher D2% for Fheads with and without an ERB. Conclusions Further optimization to the Rwall in the context of urethra sparing prostate SBRT is feasible without compromising the dose homogeneity to the target. Independent of the use or not of an ERB, low-to-intermediate doses to the Rwall can be significantly reduced using a four-step sequential optimization approach.
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Affiliation(s)
- Angèle Dubouloz
- Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1205, Genève, Switzerland. .,Radiation Oncology Department, Geneva University Hospital, CH-1211, 14, Geneva, Switzerland.
| | - Michel Rouzaud
- Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1205, Genève, Switzerland
| | - Lev Tsvang
- Department of Radiation Oncology, Chaim Sheba Medical Center, Tel-Hashomer, 52621, Ramat Gan, Israel
| | - Wilko Verbakel
- Department of Radiation Oncology, VU medical center, De Boelelaan 1117, P.O. Box 7057, 1007, MB, Amsterdam, The Netherlands
| | - Mikko Björkqvist
- Department of Oncology and Radiotherapy, Turku University Hospital, PO Box 52, 20521, Turku, Finland.,Department of Medical Physics, Turku University Hospital, PO Box 52, 20521, Turku, Finland
| | - Nadine Linthout
- Onze-Lieve-Vrouw Ziekenhuis, Moorselbaan 164, 9300, Aalst, Belgium
| | - Joana Lencart
- Serviço de Radioterapia Externa, Instituto Portugues de Oncologia, Rua Dr Antonio Bernardino de Almeida, 4200-072, Porto, Portugal
| | - Juan María Pérez-Moreno
- Servicio de Oncología Radioterápica, Centro Integral Oncológico "Clara Campal", Hospital Universitario Madrid Sanchinarro, C/ Oña 10, 28050, Madrid, Spain
| | - Zeynep Ozen
- Neolife Medical Center, Nisbetiye Mah. Yucel Sokak, No: 6 Besiktas, 34340, Istanbul, Turkey
| | - Lluís Escude
- Servei de Radiooncologia, Institut Oncològic Teknon, C/ Vilana 12, 08022, Barcelona, Spain
| | - Thomas Zilli
- Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1205, Genève, Switzerland
| | - Raymond Miralbell
- Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1205, Genève, Switzerland.,Servei de Radiooncologia, Institut Oncològic Teknon, C/ Vilana 12, 08022, Barcelona, Spain
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Richardson M, Sidhom M, Gallagher S, Grand M, Pryor D, Bucci J, Wilton L, Arumugam S, Keats S, Martin JM. PROstate Multicentre External beam radioTHErapy Using a Stereotactic boost: the PROMETHEUS study protocol. BMC Cancer 2018; 18:588. [PMID: 29793444 PMCID: PMC5968492 DOI: 10.1186/s12885-018-4511-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/16/2018] [Indexed: 11/16/2022] Open
Abstract
Background High Dose Rate Brachytherapy (HDRB) boost is a well-established treatment for prostate cancer (PC). We describe the PROstate Multicentre External beam radioTHErapy Using Stereotactic boost (PROMETHEUS) study. Non-surgical stereotactic techniques are used to deliver similar doses to HDRB boost regimens with a dose escalation sub-study. Methods Eligible patients have intermediate or high risk PC. PROMETHEUS explores the safety, efficacy and feasibility of multiple Australian centres cooperating in the delivery of Prostate Stereotactic Body Radiotherapy (SBRT) technology. A SBRT boost component Target Dose (TD) of 19Gy in two fractions is to be delivered, followed by a subsequent EBRT component of 46Gy in 23 fractions. Once accrual triggers have been met, SBRT doses can be escalated in 1 Gy increments to a maximum of 22Gy in two fractions. Patient safety will also be measured with the rate of both acute and late moderate to severe Gastro-Intestinal (GI) and Genito-Urinary (GU) Common Terminology Criteria for Adverse Events (CTCAE) toxicities as well as patient reported quality of life. Efficacy will be assessed via biochemical control after 3 years. Discussion PROMETHEUS aims to generate evidence for a non-surgical possible future alternative to HDRB boost regimens, and introduce advanced radiotherapy techniques across multiple Australian cancer centres. Trial registration The study was retrospectively registered on the ANZCTR (Australian New Zealand Clinical Trials Registry) with trial ID: ACTRN12615000223538.
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Affiliation(s)
| | - Mark Sidhom
- Liverpool and Macarthur Cancer Therapy Centres, Sydney, NSW, Australia
| | | | - Mel Grand
- Liverpool and Macarthur Cancer Therapy Centres, Sydney, NSW, Australia.,Ingham Institute, Liverpool, NSW, Australia
| | - David Pryor
- Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Joseph Bucci
- St. George Hospital Cancer Centre, Sydney, NSW, Australia
| | - Lee Wilton
- Calvary Mater Newcastle, Newcastle, NSW, Australia
| | - Sankar Arumugam
- Liverpool and Macarthur Cancer Therapy Centres, Sydney, NSW, Australia
| | - Sarah Keats
- Liverpool and Macarthur Cancer Therapy Centres, Sydney, NSW, Australia
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Legge K, Nguyen D, Ng JA, Wilton L, Richardson M, Booth J, Keall P, O'Connor DJ, Greer P, Martin J. Real-time intrafraction prostate motion during linac based stereotactic radiotherapy with rectal displacement. J Appl Clin Med Phys 2017; 18:130-136. [PMID: 28960696 PMCID: PMC5689913 DOI: 10.1002/acm2.12195] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 08/22/2017] [Accepted: 08/25/2017] [Indexed: 12/05/2022] Open
Abstract
Background Kilovoltage Intrafraction Monitoring (KIM) is a method which determines the three‐dimensional position of the prostate from two‐dimensional kilovoltage (kV) projections taken during linac based radiotherapy treatment with real‐time feedback. Rectal displacement devices (RDDs) allow for improved rectal dosimetry during prostate cancer treatment. This study used KIM to perform a preliminary investigation of prostate intrafraction motion observed in patients with an RDD in place. Methods Ten patients with intermediate to high‐risk prostate cancer were treated with a Rectafix RDD in place during two boost fractions of 9.5–10 Gy delivered using volumetric modulated arc therapy (VMAT) on Clinac iX and Truebeam linacs. Two‐dimensional kV projections were acquired during treatment. KIM software was used following treatment to determine the displacement of the prostate over time. The displacement results were analyzed to determine the percentage of treatment time the prostate spent within 1 mm, between 1 and 2 mm, between 2 and 3 mm and greater than 3 mm from its initial position. Results KIM successfully measured displacement for 19 prostate stereotactic boost fractions. The prostate was within 1 mm of its initial position for 84.8%, 1–2 mm for 14%, 2–3 mm 1.2% and ≥3 mm only 0.4% of the treatment time. Conclusions In this preliminary study using KIM, KIM was successfully used to measure prostate intrafraction motion, which was found to be small in the presence of a rectal displacement device. Trial registration The Hunter New England Human Research Ethics Committee reference number is 14/08/20/3.01.
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Affiliation(s)
- Kimberley Legge
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Doan Nguyen
- Radiation Physics Laboratory, University of Sydney, Sydney, NSW, Australia
| | - Jin Aun Ng
- Radiation Physics Laboratory, University of Sydney, Sydney, NSW, Australia
| | - Lee Wilton
- Radiation Oncology Department, Calvary Mater Newcastle, Newcastle, NSW, Australia
| | - Matthew Richardson
- Radiation Oncology Department, Calvary Mater Newcastle, Newcastle, NSW, Australia
| | - Jeremy Booth
- Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Paul Keall
- Radiation Physics Laboratory, University of Sydney, Sydney, NSW, Australia
| | - Darryl J O'Connor
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Peter Greer
- Radiation Oncology Department, Calvary Mater Newcastle, Newcastle, NSW, Australia
| | - Jarad Martin
- Hunter Region Mail Centre, Calvary Mater Newcastle, Newcastle, NSW, Australia
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11
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Legge K, Greer PB, O'Connor DJ, Wilton L, Richardson M, Hunter P, Wilfert A, Martin J, Rosenfeld A, Cutajar D. Real-time in vivo rectal wall dosimetry using MOSkin detectors during linac based stereotactic radiotherapy with rectal displacement. Radiat Oncol 2017; 12:41. [PMID: 28241841 PMCID: PMC5327549 DOI: 10.1186/s13014-017-0781-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 02/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND MOSFET dosimetry is a method that has been used to measure in-vivo doses during brachytherapy treatments and during linac based radiotherapy treatment. Rectal displacement devices (RDDs) allow for safe dose escalation for prostate cancer treatment. This study used dual MOSkin detectors to assess real-time in vivo rectal wall dose in patients with an RDD in place during a high dose prostate stereotactic body radiation therapy (SBRT) boost trial. METHODS The PROMETHEUS study commenced in 2014 and provides a prostate SBRT boost dose with a RDD in place. Twelve patients received two boost fractions of 9.5-10 Gy each delivered to the prostate with a dual arc volumetric modulated arc therapy (VMAT) technique. Two MOSkins in a face-to-face arrangement (dual MOSkin) were used to decrease angular dependence. A dual MOSkin was attached to the anterior surface of the Rectafix and read out at 1 Hz during each treatment. The planned dose at each measurement point was exported from the planning system and compared with the measured dose. The root mean square error normalised to the total planned dose was calculated for each measurement point and treatment arc for the entire course of treatment. RESULTS The average difference between the measured and planned doses over the whole course of treatment for all arcs measured was 9.7% with a standard deviation of 3.6%. The cumulative MOSkin reading was lower than the total planned dose for 64% of the arcs measured. The average difference between the final measured and final planned doses for all arcs measured was 3.4% of the final planned dose, with a standard deviation of 10.3%. CONCLUSIONS MOSkin detectors were an effective tool for measuring dose delivered to the anterior rectal wall in real time during prostate SBRT boost treatments for the purpose of both ensuring the rectal doses remain within acceptable limits during the treatment and for the verification of final rectal doses.
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Affiliation(s)
- Kimberley Legge
- University of Newcastle, University Drive, Callaghan, 2308, NSW, Australia.
| | - Peter B Greer
- University of Newcastle, University Drive, Callaghan, 2308, NSW, Australia.,Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | - Daryl J O'Connor
- University of Newcastle, University Drive, Callaghan, 2308, NSW, Australia
| | - Lee Wilton
- Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | - Matthew Richardson
- Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | - Perry Hunter
- Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | - Alex Wilfert
- Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | - Jarad Martin
- Calvary Mater Newcastle, Cnr Edith and Platt Streets, Waratah, 2298, NSW, Australia
| | | | - Dean Cutajar
- University of Wollongong, Wollongong, 2522, NSW, Australia
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12
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Vanhanen A, Kapanen M. The effect of rectal retractor on intrafraction motion of the prostate. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/3/035021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Gasinska A. The contribution of women to radiobiology: Marie Curie and beyond. Rep Pract Oncol Radiother 2016; 21:250-8. [PMID: 27601958 PMCID: PMC5002019 DOI: 10.1016/j.rpor.2015.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/26/2015] [Accepted: 11/30/2015] [Indexed: 01/09/2023] Open
Abstract
Marie Sklodowska-Curie, an extraordinary woman, a Polish scientist who lived and worked in France, led to the development of nuclear energy and the treatment of cancer. She was the laureate of two Nobel Prizes, the first woman in Europe who obtained the degree of Doctor of Science and opened the way for women to enter fields which had been previously reserved for men only. As a result of her determination and her love of freedom, she has become an icon for many female scientists active in radiation sciences. They are successors of Maria Curie and without the results of their work, improvement in radiation oncology will not be possible. Many of them shared some elements of Maria Curie's biography, like high ethical and moral standards, passionate dedication to work, strong family values, and scientific collaboration with their husbands. The significance of Tikvah Alper, Alma Howard, Shirley Hornsey, Juliana Denekamp, Helen Evans, Eleanor Blakely, Elizabeth L. Travis, Fiona Stewart, Andree Dutreix, Catharine West, Peggy Olive, Ingela Turesson, Penny Jeggo, Irena Szumiel, Eleonor Blakely, Sara Rockwell and Carmel Mothersill contribution to radiation oncology is presented. All the above mentioned ladies made significant contribution to the development of radiotherapy (RT) and more efficient cancer treatment. Due to their studies, new schedules of RT and new types of ionizing radiation have been applied, lowering the incidence of normal tissue toxicity. Their achievements herald a future of personalized medicine.
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Affiliation(s)
- Anna Gasinska
- Department of Applied Radiobiology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Cracow Branch, Poland
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14
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Nicolae A, Davidson M, Easton H, Helou J, Musunuru H, Loblaw A, Ravi A. Clinical evaluation of an endorectal immobilization system for use in prostate hypofractionated Stereotactic Ablative Body Radiotherapy (SABR). Radiat Oncol 2015; 10:122. [PMID: 26024900 PMCID: PMC4456701 DOI: 10.1186/s13014-015-0426-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/21/2015] [Indexed: 11/16/2022] Open
Abstract
Background The objective of this study was to evaluate a novel prostate endorectal immobilization system (EIS) for improving the delivery of hypofractionated Stereotactic Ablative Body Radiotherapy (SABR) for prostate cancer. Methods Twenty patients (n = 20) with low- or intermediate-risk prostate cancer (T1-T2b, Gleason Score < 7, PSA ≤ 20 ng/mL), were treated with an EIS in place using Volumetric Modulated Arc Therapy (VMAT), to a prescription dose of 26 Gy delivered in 2 fractions once per week; the intent of the institutional clinical trial was an attempt to replicate brachytherapy-like dosimetry using SABR. EBT3 radiochromic film embedded within the EIS was used as a quality assurance measure of the delivered dose; additionally, prostate intrafraction motion captured using pre- and post-treatment conebeam computed tomography (CBCT) scans was evaluated. Treatment plans were generated for patients with- and without the EIS to evaluate its effects on target and rectal dosimetry. Results None of the observed 3-dimensional prostate displacements were ≥ 3 mm over the elapsed treatment time. A Gamma passing rate of 95.64 ± 4.28 % was observed between planned and delivered dose profiles on EBT3 film analysis in the low-dose region. No statistically significant differences between treatment plans with- and without-EIS were observed for rectal, bladder, clinical target volume (CTV), and PTV contours (p = 0.477, 0.484, 0.487, and 0.487, respectively). A mean rectal V80% of 1.07 cc was achieved for plans using the EIS. Conclusions The EIS enables the safe delivery of brachytherapy-like SABR plans to the prostate while having minimal impact on treatment planning and rectal dosimetry. Consistent and reproducible immobilization of the prostate is possible throughout the duration of these treatments using such a device.
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Affiliation(s)
- Alexandru Nicolae
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
| | - Melanie Davidson
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. .,Department of Radiation Oncology, The University of Toronto, Toronto, Ontario, Canada.
| | - Harry Easton
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
| | - Joelle Helou
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
| | - Hima Musunuru
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
| | - Andrew Loblaw
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. .,Department of Radiation Oncology, The University of Toronto, Toronto, Ontario, Canada.
| | - Ananth Ravi
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. .,Department of Radiation Oncology, The University of Toronto, Toronto, Ontario, Canada.
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15
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Alnaghy SJ, Deshpande S, Cutajar DL, Berk K, Metcalfe P, Rosenfeld AB. In vivo endorectal dosimetry of prostate tomotherapy using dual MOSkin detectors. J Appl Clin Med Phys 2015; 16:5113. [PMID: 26103477 PMCID: PMC5690127 DOI: 10.1120/jacmp.v16i3.5113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 01/06/2015] [Accepted: 01/06/2015] [Indexed: 11/23/2022] Open
Abstract
Verification of dose to the anterior rectal wall in helical tomotherapy to the prostate is important due to the close proximity of the rectal wall to the treatment field. The steep dose gradient makes these measurements challenging. A phantom-based study was completed, aimed at developing a system for measurement of anterior rectal wall doses during hypofractionated prostate stereotactic body radiotherapy (SBRT) utilizing tomotherapy delivery. An array of four dual MOSkinTM dosimeters, spaced 1 cm apart, was placed on a replica Rectafix® immobilization spacer device. This Perspex probe is a more rigid alternative to rectal balloons, to improve geometric reproducibility. The doses at each point were measured in real time and compared to doses calculated by the treatment planning system (TPS). Additionally, distance-to-agreement (DTA) measurements were acquired to assist in the comparison of measured and predicted doses. All dual MOSkin detectors measured dose to within ± 5% of the TPS at the anterior rectal wall. Whilst several points were outside of experimental error, the largest deviation from the TPS predicted dose represented a DTA of only 1.3 mm, within the acceptable DTA tolerance of 3 mm. Larger deviations of up to -11.9% were observed for the posterior and side walls; however, if acceptable DTA measurements are accounted for, then an agreement of 75% was observed. Although larger differences were observed at the other rectal wall locations, the overall effect of dose at these points was not as significant, given the lower doses. Despite the very high-dose gradient region, real-time measurements of the anterior rectal wall doses were within acceptable limits of TPS-predicted doses. The differences between measured and planned data were due to difficulties in precisely locating each detector on the TPS dose grid, which presented large variations in dose between CT voxels in regions of steep dose gradients. The dual MOSkin system would, therefore, be a useful device for detecting errors in real time, such as patient shifts or incorrect setup, during tomotherapy of the prostate.
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Affiliation(s)
- Sarah J Alnaghy
- Centre for Medical Radiation Physics, University of Wollongong.
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16
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Tilly D, Tilly N, Ahnesjö A. Dose mapping sensitivity to deformable registration uncertainties in fractionated radiotherapy - applied to prostate proton treatments. BMC MEDICAL PHYSICS 2013; 13:2. [PMID: 23768107 PMCID: PMC3701614 DOI: 10.1186/1756-6649-13-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 02/27/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND Calculation of accumulated dose in fractionated radiotherapy based on spatial mapping of the dose points generally requires deformable image registration (DIR). The accuracy of the accumulated dose thus depends heavily on the DIR quality. This motivates investigations of how the registration uncertainty influences dose planning objectives and treatment outcome predictions.A framework was developed where the dose mapping can be associated with a variable known uncertainty to simulate the DIR uncertainties in a clinical workflow. The framework enabled us to study the dependence of dose planning metrics, and the predicted treatment outcome, on the DIR uncertainty. The additional planning margin needed to compensate for the dose mapping uncertainties can also be determined. We applied the simulation framework to a hypofractionated proton treatment of the prostate using two different scanning beam spot sizes to also study the dose mapping sensitivity to penumbra widths. RESULTS The planning parameter most sensitive to the DIR uncertainty was found to be the target D95. We found that the registration mean absolute error needs to be ≤0.20 cm to obtain an uncertainty better than 3% of the calculated D95 for intermediate sized penumbras. Use of larger margins in constructing PTV from CTV relaxed the registration uncertainty requirements to the cost of increased dose burdens to the surrounding organs at risk. CONCLUSIONS The DIR uncertainty requirements should be considered in an adaptive radiotherapy workflow since this uncertainty can have significant impact on the accumulated dose. The simulation framework enabled quantification of the accuracy requirement for DIR algorithms to provide satisfactory clinical accuracy in the accumulated dose.
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Affiliation(s)
- David Tilly
- Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden
- Elekta Instruments AB, Uppsala, 753 21, Sweden
| | - Nina Tilly
- Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden
- Elekta Instruments AB, Uppsala, 753 21, Sweden
| | - Anders Ahnesjö
- Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden
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Sjöberg C, Ahnesjö A. Multi-atlas based segmentation using probabilistic label fusion with adaptive weighting of image similarity measures. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2013; 110:308-319. [PMID: 23339900 DOI: 10.1016/j.cmpb.2012.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 12/13/2012] [Accepted: 12/28/2012] [Indexed: 06/01/2023]
Abstract
Label fusion multi-atlas approaches for image segmentation can give better segmentation results than single atlas methods. We present a multi-atlas label fusion strategy based on probabilistic weighting of distance maps. Relationships between image similarities and segmentation similarities are estimated in a learning phase and used to derive fusion weights that are proportional to the probability for each atlas to improve the segmentation result. The method was tested using a leave-one-out strategy on a database of 21 pre-segmented prostate patients for different image registrations combined with different image similarity scorings. The probabilistic weighting yields results that are equal or better compared to both fusion with equal weights and results using the STAPLE algorithm. Results from the experiments demonstrate that label fusion by weighted distance maps is feasible, and that probabilistic weighted fusion improves segmentation quality more the stronger the individual atlas segmentation quality depends on the corresponding registered image similarity. The regions used for evaluation of the image similarity measures were found to be more important than the choice of similarity measure.
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Affiliation(s)
- C Sjöberg
- Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Avd. för sjukhusfysik, ing. 81, S-751 85 Uppsala, Sweden.
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Hypofractionated proton boost combined with external beam radiotherapy for treatment of localized prostate cancer. Prostate Cancer 2012; 2012:654861. [PMID: 22848840 PMCID: PMC3399336 DOI: 10.1155/2012/654861] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 04/17/2012] [Indexed: 11/18/2022] Open
Abstract
Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT) of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT). The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU) and gastrointestinal (GI) toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity.
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Däpp S, Müller C, Garayoa EG, Bläuenstein P, Maes V, Brans L, Tourwé DA, Schibli R. PEGylation, increasing specific activity and multiple dosing as strategies to improve the risk-benefit profile of targeted radionuclide therapy with 177Lu-DOTA-bombesin analogues. EJNMMI Res 2012; 2:24. [PMID: 22681935 PMCID: PMC3478187 DOI: 10.1186/2191-219x-2-24] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 06/09/2012] [Indexed: 12/05/2022] Open
Abstract
Background Radiolabelled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumours, in which BN2/gastrin-releasing peptide receptors are overexpressed. We describe the influence of the specific activity of a 177Lu-DOTA-PEG5k-Lys-B analogue on its therapeutic efficacy and compare it with its non-PEGylated counterpart. Methods Derivatisation of a stabilised DOTA-BN(7–14)[Cha13,Nle14] analogue with a linear PEG molecule of 5 kDa (PEG5k) was performed by PEGylation of the ϵ-amino group of a β3hLys-βAla-βAla spacer between the BN sequence and the DOTA chelator. The non-PEGylated and the PEGylated analogues were radiolabelled with 177Lu. In vitro evaluation was performed in human prostate carcinoma PC-3 cells, and in vivo studies were carried out in nude mice bearing PC-3 tumour xenografts. Different specific activities of the PEGylated BN analogue and various dose regimens were evaluated concerning their therapeutic efficacy. Results The specificity and the binding affinity of the BN analogue for BN2/GRP receptors were only slightly reduced by PEGylation. In vitro binding kinetics of the PEGylated analogue was slower since steady-state condition was reached after 4 h. PEGylation improved the stability of BN conjugate in vitro in human plasma by a factor of 5.6. The non-PEGylated BN analogue showed favourable pharmacokinetics already, i.e. fast blood clearance and renal excretion, but PEGylation improved the in vivo behaviour further. One hour after injection, the tumour uptake of the PEG5k-BN derivative was higher compared with that of the non-PEGylated analogue (3.43 ± 0.63% vs. 1.88 ± 0.4% ID/g). Moreover, the increased tumour retention resulted in a twofold higher tumour accumulation at 24 h p.i., and increased tumour-to-non-target ratios (tumour-to-kidney, 0.6 vs. 0.4; tumour-to-liver, 8.8 vs. 5.9, 24 h p.i.). In the therapy study, both 177Lu-labelled BN analogues significantly inhibited tumour growth. The therapeutic efficacy was highest for the PEGylated derivative of high specific activity administered in two fractions (2 × 20 MBq = 40 MBq) at day 0 and day 7 (73% tumour growth inhibition, 3 weeks after therapy). Conclusions PEGylation and increasing the specific activity enhance the pharmacokinetic properties of a 177Lu-labelled BN-based radiopharmaceutical and provide a protocol for targeted radionuclide therapy with a beneficial anti-tumour effectiveness and a favourable risk-profile at the same time.
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Affiliation(s)
- Simone Däpp
- Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Villigen-PSI, 5232, Switzerland.
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20
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Pettersson A, Johansson B, Persson C, Berglund A, Turesson I. Effects of a dietary intervention on acute gastrointestinal side effects and other aspects of health-related quality of life: a randomized controlled trial in prostate cancer patients undergoing radiotherapy. Radiother Oncol 2012; 103:333-40. [PMID: 22633817 DOI: 10.1016/j.radonc.2012.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 10/17/2011] [Accepted: 04/28/2012] [Indexed: 01/04/2023]
Abstract
PURPOSE To study the effect of a dietary intervention on acute gastrointestinal side effects and other aspects of health-related quality of life (HRQOL) in prostate cancer patients referred to radiotherapy. MATERIALS AND METHODS A total of 130 patients were randomly assigned to one of two groups: an intervention group (IG, n=64), instructed to reduce their intake of insoluble dietary fibres and lactose, a standard care group (SC, n=66), instructed to continue their normal diet. Gastrointestinal side effects and other aspects of HRQOL were evaluated from baseline up to 2 months after completed radiotherapy, using the EORTC QLQ-C30 and QLQ-PR25 and the study-specific Gastrointestinal Side Effects Questionnaire (GISEQ). A scale indicating adherence to dietary instructions was developed from a Food Frequency Questionnaire (FFQ), with lower scores representing better compliance. Descriptive and inferential statistical analyses were conducted. RESULTS There was an interaction effect between randomization and time in the FFQ Scores (p<0.001), indicating that both groups followed their assigned dietary instructions. The dietary intervention had no effect on gastrointestinal side effects or other aspects of HRQOL. During radiotherapy, the percentage of patients with bowel symptoms and bloated abdomen was lower in IG compared to SC, but the between-group differences were not statistically significant. During radiotherapy, the percentage of patients with bowel symptoms, urinary symptoms, pain, fatigue and diminished physical and role functioning increased in both groups. CONCLUSIONS The dietary intervention had no effect on gastrointestinal side effects or other aspects of HRQOL. The tendency towards lower prevalence of bowel symptoms in IG may indicate some positive effect of the dietary intervention, but methodological refinements, clearer results and longer follow-up are needed before the value of diet change can be established with certainty.
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Affiliation(s)
- Anna Pettersson
- Department of Radiology, Oncology and Radiation Science, Uppsala University, Uppsala, Sweden.
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21
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Lennernäs B, Castellanos E, Nilsson S, Levitt S. Four and five dimensional radiotherapy with reference to prostate cancer--definitions, state of the art and further directions--an overview. Acta Oncol 2011; 50 Suppl 1:104-10. [PMID: 21604949 DOI: 10.3109/0284186x.2010.530003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Radiotherapy (RT) always requires a compromise between tumor control and normal tissue side-effects. Technical innovation in radiation therapy (RT), such as three dimensional RT, is now established. Concerning prostate cancer (PC), it is reasonable to assume that RT of PC will increase in the future. The combination of small margins, a movable target (prostate), few fractions and high doses will probably demand dynamically positioning systems and in real time. This is called four dimensional radiotherapy (4DRT). Moreover, biological factors must be included in new treatments such as hypofractionation schedules. This new era is called five dimensional radiotherapy, 5DRT. In this paper we discuss new concepts in RT in respect to PC.
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Affiliation(s)
- Bo Lennernäs
- Department of Oncology, Sahlgrenska Hospital and Academy, University of Gothenburg, Gothenburg, Sweden.
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Herrmann R, Carl J, Jäkel O, Bassler N, Petersen JBB. Investigation of the dosimetric impact of a Ni-Ti fiducial marker in carbon ion and proton beams. Acta Oncol 2010; 49:1160-4. [PMID: 20831508 DOI: 10.3109/0284186x.2010.505934] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Fiducial markers based on a removable stent are currently used in image guided radiotherapy. Here it is investigated what the possible dosimetric impact of such a marker could be, if used in proton or carbon ion treatment. MATERIAL AND METHODS The simulations have been done using the Monte Carlo particle transport code FLUKA with its default hadron therapy settings. A 3 cm long stent is approximated in FLUKA by stacking hollow tori. To simulate realistic clinical conditions a field 5 × 5 cm has been used, delivering a 5 cm wide spread out Bragg peak located 5 cm deep for protons and carbon ions. For protons fields mimicking active and passive beam delivery have been investigated. The stent has been arranged perpendicular, turned 45 degrees, and parallel to the beam axis. RESULTS The position of the 95% dose level shifts for carbon ions 7 mm in proximal direction for the marker perpendicular to the beam and 8 mm if the stent is turned 45 degree for a 1 × 1 cm dose binning on the centre beam axis. For the case where the stent was parallel to beam direction the 95% dose level shifts 26 mm. For active delivered protons, the shift of the 95% dose level is less. The shift for a perpendicular arranged marker is 6 mm, for 45 degrees turned it is 7 mm. For the case where the stent was oriented parallel to the beam, the observed shift is 21 mm. Dose inhomogeneities caused by straggling effects occur only near the distal edge of the field. CONCLUSIONS The results of our investigations show that the Ni-Ti marker has a non negligible impact on the dose distributions for the used radiation types. However if the treatment plan rules out narrow angles between symmetry axis of the stent and the beam direction, this may be compensated.
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Affiliation(s)
- Rochus Herrmann
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark.
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