Volumetric modulated arc therapy for treatment of solid tumors: current insights

OncoTargets and Therapy Dovepress open access to scientific and medical research Review Open Access Full Text Article OncoTargets and Therapy downloaded from https://www.dovepress.com/ by 37.59.46.207 on 13-Jul-2018 For personal use only. Volumetric modulated arc therapy for treatment of solid tumors: current insights This article was published in the following Dove Press journal: OncoTargets and Therapy 26 July 2017 Number of times this article has been viewed Gabriella Macchia 1 Francesco Deodato 1 Savino Cilla 2 Silvia Cammelli 3 Alessandra Guido 3 Martina Ferioli 3 Giambattista Siepe 3 Vincenzo Valentini 4 Alessio Giuseppe Morganti 3,* Gabriella Ferrandina 5,6,* Radiation Oncology Unit, 2Medical Physics Unit, “Giovanni Paolo II” Foundation, Catholic University of the Sacred Heart, Campobasso, 3Radiation Oncology Unit, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, S. Orsola‑Malpighi Hospital, Bologna, 4 Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome, 5Department of Obstetrics and Gynecology, Catholic University of the Sacred Heart, Rome, 6 Department of Health Sciences and Medicine, University of Molise, Campobasso, Italy 1 *These authors contributed equally to this work Correspondence: Francesco Deodato Radiation Oncology Unit, “Giovanni Paolo II” Foundation, Catholic University of the Sacred Heart, Largo Gemelli 1, 86100, Campobasso, Italy Tel +39 0874 312 259 Fax +39 0874 312 720 Email Introduction Since the introduction of intensity-modulated radiotherapy (IMRT) in clinical routine in the late 1990s, a very fast growth has characterized radiotherapy (RT) technology offering newer technologies and techniques to radiation oncologists. Indeed, IMRT,1 helical tomotherapy,2 intensity-modulated arc therapy (IMAT),3 and volumetric modulated arc therapy (VMAT)4 enable better radiation dose conformality to the target volume compared to three-dimensional conformal radiotherapy (3D-CRT). Moreover, these techniques, which underlie various complex computer-based optimization algorithms, allowed the delivery of nonuniform radiation beam intensities in order to obtain highly conformal dose distributions, thus potentially resulting in RT dose escalation to the target with an improved cancer control. Moreover, they allowed the delivery of simultaneous integrated boost (SIB), a technique that permits treating of several volumes safely with different dose prescriptions, thus leading to reduction of the dose to the surrounding radiation-sensitive normal tissues and improvement of the toxicity profile. 3755 submit your manuscript | www.dovepress.com OncoTargets and Therapy 2017:10 3755–3772 Dovepress © 2017 Macchia et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). http://dx.doi.org/10.2147/OTT.S113119 Powered by TCPDF (www.tcpdf.org) Aim: This article discusses the current use of volumetric modulated arc therapy (VMAT) techniques in clinical practice and reviews the available data from clinical outcome studies in different clinical settings. An overview of available literature about clinical outcomes with VMAT stereotactic/radiosurgical treatment is also reported. Materials and methods: All published manuscripts reporting the use of VMAT in a clinical setting from 2009 to November 2016 were identified. The search was carried out in December 2016 using the National Library of Medicine (PubMed/Medline). The following words were searched: “volumetric arc therapy”[All Fields] OR “vmat”[All Fields] OR “rapidarc”[All Fields], AND “radiotherapy”[All Fields] AND “Clinical Trial”[All Fields]. Results: Overall, 37 studies (21 prospective and 16 retrospective) fulfilling inclusion criteria and thus included in the review evaluated 2,029 patients treated with VMAT; of these patients, ~30.8% had genitourinary (GU) tumors (81% prostate, 19% endometrial), 26.2% head-and-neck cancer (H&NC), 13.9% oligometastases, 11.2% had anorectal cancer, 10.6% thoracic neoplasms (81% breast, 19% lung), and 7.0% brain metastases (BMs). Six different clinical scenarios for VMAT use were identified: 1) BMs, 2) H&NC, 3) thoracic neoplasms, 4) GU cancer, 5) anorectal tumor, and 6) stereotactic body radiation therapy (SBRT) performed by VMAT technique in the oligometastatic patient setting. Conclusion: The literature addressing the clinical appropriateness of VMAT is scarce. Current literature suggests that VMAT, especially when used as simultaneous integrated boost or SBRT strategy, is an effective safe modality for all cancer types. Keywords: VMAT, RapidArc, clinical trial, review, radiosurgery, stereotactic, simultaneous integrated boost Dovepress OncoTargets and Therapy downloaded from https://www.dovepress.com/ by 37.59.46.207 on 13-Jul-2018 For personal use only. Macchia et al In this context, VMAT represents the newest RT technique and can provide additional advantages, such as reduced treatment delivery time compared with conventional static field IMRT. In fact, in VMAT delivery, field shapes, dose rate, and gantry rotation speed can simultaneously vary. These additional degrees of freedom increased the capability of beam intensity modulation with respect to IMAT. Based on Otto’s VMAT algorithm,4 Varian (Palo Alto, CA, USA) implemented the single-arc form of IMAT and named the system RapidArcTM®. Elekta (Stockholm, Sweden) and Philips (Amsterdam, the Netherlands) also released their rotational IMRT solutions, named VMAT® and SmartArcTM®, respectively. Since the clinical implementation of these different rotational forms of IMRT by different vendors, the feasibility of applying this novel delivery technique to different cancer sites has been widely explored. Theoretical investigation and a very large number of treatment planning studies have extensively addressed the differences among VMAT, 3D-CRT, IMRT, and helical tomotherapy.5–15 In the last decade, technological improvements in setup, imaging, accuracy in dose delivery, and the ability to compensate for respiratory motion have led to a widespread clinical implementation of stereotactic body radiation therapy (SBRT), also named as stereotactic ablative radiotherapy (SABR). SBRT refers to the delivery of large focused doses over a limited number of fractions to tumor sites, in order to obtain the highest biological effective dose. Because of its rotational nature and its fast delivery timing, (...truncated)