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Dosimetric variations for high-risk prostate cancer by VMAT plans due to patient’s weight changes

Published online by Cambridge University Press:  21 May 2019

David Miguel Open the ORCID record for David Miguel [Opens in a new window] ,
Victor de la Llana ,
Daniel Martinez ,
Angel del Castillo ,
Delfín Alonso ,
Jesús-María de Frutos ,
Carlos Andrés ,
Manuel Agulla ,
Ricardo Torres  and
Francisco López-Lara
David Miguel*
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Victor de la Llana
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Daniel Martinez
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Angel del Castillo
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Delfín Alonso
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Jesús-María de Frutos
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Carlos Andrés
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Manuel Agulla
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Ricardo Torres
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Francisco López-Lara
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
*
Author for correspondence: David Miguel, Hospital Clinico Universitario de Valladolid, Valladolid 47014, Spain. E-mail: [email protected]
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Abstract

Purpose:

The aim of this study is to investigate the impact of anatomical changes in prostate cancer patients on the target coverage when using 6 MV beams-VMAT therapy and to propose strategies that allow us to evaluate the dose or correct it by normalization without having to perform a new simulation.

Methods and materials:

Ten patients of high-risk prostate cancer were chosen for the study. All test plans were delivered using the same isocenter and monitor units as the original plan and compared against the original unedited plan. The expansion and contraction of body contours due to size changes was mimicked by increasing and decreasing the body contour with depths of −2, −1·5, …, 1·5, 2 cm, in the anterior, and both lateral directions of the patient. A total of 90 plans were evaluated, 9 for each patient. Dose-volume histogram statistics were extracted from each plan and normalized to prescription dose.

Results:

Weight changes resulted in considerable dose modifications to the target and critical structures. Plans were found to be varied with 2·9% ± 0·3% per cm SSD change for VMAT treatment with a correlation index close to one. Therefore, doses variations were linear to the changes of depth. Gamma index evaluation was performed for the 10 renormalized plans. All of them passed criteria of 3%/3 mm in at least 98.2% of points. Eight of them passed criteria in 99% points. Gamma index 4%/4 mm passed 100% points in all patients for the chosen region of interest.

Conclusions:

The dosimetry estimation presented in this study shows important data for the radiation oncology staff to justify whether a CT rescan is necessary or not when a patient experiences weight changes during treatment. Based on the results of our study, discrepancies between real dose and planned dose were >5% for 1·7 cm of difference in external contour in the anterior and both lateral directions of the patient.

Keywords

dosevolume pointspatient’s weight changesprostatetreatment planning evaluationVMAT
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 18 , Issue 4 , December 2019 , pp. 336 - 342
Copyright
© Cambridge University Press 2019 

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References

Torre, L A, Bray, F, Siegel, R L, Ferlay, J, Lortet-Tieulent, J, Jemal, A. Global cancer statistics, 2012. CA Cancer J Clin 2015; 65 (2): 87–108.10.3322/caac.21262CrossRefGoogle ScholarPubMed
Mottet, N, Bellmunt, J, Bolla, M et al. EAU-ESTRO-SIOG Guidelines on Prostate Cancer. Part 1: Screening, Diagnosis, and Local Treatment with Curative Intent. Eur Urol 2017; 71 (4): 618–629.10.1016/j.eururo.2016.08.003CrossRefGoogle ScholarPubMed
Pollack, A, Hanlon, A L, Horwitz, E M et al. Dosimetry and preliminary acute toxicity in the first 100 men treated for prostate cancer on a randomized hypofractionation dose escalation trial. Int J Radiat Oncol 2006; 64 (2): 518–526.10.1016/j.ijrobp.2005.07.970CrossRefGoogle ScholarPubMed
Nguyen, N P, Davis, R, Bose, S R et al. International Geriatric Radiotherapy Group the IGR. Potential applications of image-guided radiotherapy for radiation dose escalation in patients with early stage high-risk prostate cancer. Front Oncol 2015; 5 (18): 1–7.10.3389/fonc.2015.00018CrossRefGoogle Scholar
Rodriguez, C, Freedland, S J, Deka, A et al. Body mass index, weight change, and risk of prostate cancer in the cancer prevention study II nutrition cohort. Cancer Epidemiol Biomarkers Prev 2007; 16 (1): 63–69.10.1158/1055-9965.EPI-06-0754CrossRefGoogle ScholarPubMed
Bolze, M S, Fosmire, G J, Stryker, J A, Chung, C K, Flipse, B G. Taste acuity, plasma zinc levels, and weight loss during radiotherapy: a study of relationships. Radiology 1982; 144 (1): 163–169.10.1148/radiology.144.1.7089250CrossRefGoogle ScholarPubMed
Houweling, A C, Fukata, K, Kubota, Y et al. The impact of interfractional anatomical changes on the accumulated dose in carbon ion therapy of pancreatic cancer patients. Radiother Oncol 2016; 119 (2): 319–325.10.1016/j.radonc.2016.03.004CrossRefGoogle ScholarPubMed
Choi, H S, Jo, G S, Chae, J P et al. Defining the optimal time of adaptive replanning in prostate cancer patients with weight change during volumetric arc radiotherapy: a dosimetric and mathematical analysis using the gamma index. Comput Math Methods Med 2017; 2017: 4149591.10.1155/2017/4149591CrossRefGoogle ScholarPubMed
Pair, M L, Du, W, Rojas, H D et al. Dosimetric effects of weight loss or gain during volumetric modulated arc therapy and intensity-modulated radiation therapy for prostate cancer. Med Dosim 2013; 38 (3): 251–254.10.1016/j.meddos.2013.02.004CrossRefGoogle ScholarPubMed
Chow, J C L, Jiang, R. Dosimetry estimation on variations of patient size in prostate volumetric-modulated arc therapy. Med Dosim 2013; 38 (1): 42–47.10.1016/j.meddos.2012.05.005CrossRefGoogle ScholarPubMed
Chow, J C L, Jiang, R. Comparison of dosimetric variation between prostate IMRT and VMAT due to patient’s weight loss: patient and phantom study. Reports Pract Oncol Radiother 2013; 18 (5): 272–278.10.1016/j.rpor.2013.05.003CrossRefGoogle ScholarPubMed
Low, D A, Harms, W B, Mutic, S, Purdy, J A. A technique for the quantitative evaluation of dose distributions. Med Phys 1998; 25 (5): 656–661.10.1118/1.598248CrossRefGoogle ScholarPubMed
Low, D A, Harms, W B, Mutic, S, Purdy, J A. A technique for the quantitative evaluation of dose distributions. Med Phys 1998; 25 (5): 656–661.10.1118/1.598248CrossRefGoogle ScholarPubMed
Mans, A, Schuring, D, Arends, M P et al. The NCS code of practice for the quality assurance and control for volumetric modulated arc therapy. Phys Med Biol 2016; 61 (19): 7221–7235.10.1088/0031-9155/61/19/7221CrossRefGoogle ScholarPubMed
Cutright, D, Gopalakrishnan, M, Roy, A, Panchal, A, Mittal, B B. DVH Analytics: a DVH database for clinicians and researchers. J Appl Clin Med Phys 2018; 19 (5): 413–427.10.1002/acm2.12401CrossRefGoogle ScholarPubMed
Williams, G, Tobler, M, Leavitt, D. Pitfalls in normalization for intensity-modulated radiation therapy planning. Med Dosim 2005; 30 (4): 194–200.10.1016/j.meddos.2005.06.003CrossRefGoogle ScholarPubMed
Kouloulias, V E. Quality assurance in radiotherapy. Eur J Cancer 2003; 39 (4): 415–422.10.1016/S0959-8049(02)00461-6CrossRefGoogle ScholarPubMed
Klein, E E, Drzymala, R E, Purdy, J A, Michalski, J. Errors in radiation oncology: a study in pathways and dosimetric impact. J Appl Clin Med Phys 2005; 6 (3): 81–94.10.1120/jacmp.v6i3.2105CrossRefGoogle ScholarPubMed