Volumetric modulated arc therapy (VMAT): a review of clinical outcomes—what is the clinical evidence for the most effective implementation?

Abstract

Modern conformal radiation therapy using techniques such as modulation, image guidance and motion management have changed the face of radiotherapy today offering superior conformity, efficiency, and reproducibility to clinics worldwide. This review assesses the impact of these advanced radiotherapy techniques on patient toxicity and survival rates reported from January 2017 to September 2020. The main aims are to establish if dosimetric and efficiency gains correlate with improved survival and reduced toxicities and to answer the question ‘Has VMAT become the gold standard of radiotherapy?’. Compared with 3DCRT, improvements have been reported with VMAT in prostate, locally advanced cervical carcinoma and various head and neck applications which leading to the shift in technology to VMAT. Other sites have observed improvement with VMAT however, the burden of toxicity and the incidence of cancer related deaths remain high signalling the need to further mitigate toxicity and increase survival. As technological advancement continues, large randomized long-term clinical trials are required to determine the way-forward and offer site-specific recommendations. These studies are usually expensive and time consuming therefore utilizing pooled real-world data in a prospective nature can be an alternative solution to comprehensively assess the efficacy of modern radiotherapy techniques.

Transition from 3D conformal to modern modulated craniospinal radiotherapy

“…19 Long-term sequelae, such as endocrine dysfunction, were also mentioned by Sharma et al and Packer et al 2,18 A VMAT clinical review by Hunte et al referred to reduced neurocognitive function when the hippocampus was irradiated during the treatment of multiple brain metastases. 11 Hence, sparing the hippocampus would lessen the probability of neurocognitive and endocrine dysfunction. In this study, it was difficult to spare the hippocampi since the entire brain was irradiated.…”

“…A literature review of dosimetry effectiveness amongst 3D conformal radiation therapy (CRT), intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) during CSI establishes that VMAT yields the highest degree of conformality and widest low-dose bath at 2 Gy, whilst IMRT is most homogeneous, and organs at risk (OARs) are at the highest radiation risk with 3D CRT. 3,4,5,6,7,8,9,10,11 The aim of this study is to determine which of the three radiation therapy (RT) techniques (3D CRT, IMRT and VMAT) will be most effective in treating craniospinal tumours at a Western Cape hospital by evaluating the dosevolume distribution across the planned target volumes (PTV), OARs and total irradiated volume, as well as comparing time taken to contour, generate treatment plans, assure quality and deliver radiation beams per technique. Volumetric modulated arc therapy has been established as the most effective technique for CSI.…”

Comparative Study of Eclipse and RayStation Multi-Criteria Optimization-Based Prostate Radiotherapy Treatment Planning Quality

“…Eclipse version 16.1 and RayStation version 12A were used for MCO-based treatment planning for each included CT dataset with TrueBeam linear accelerator and Millennium multi-leave collimator (Varian Medical Systems, Inc., Palo Alto, CA, USA), 2 full arcs and beam energy of 6 MV photons selected [ 31 , 32 ]. The first and second arcs rotated from 175 to 185 degrees counterclockwise, and from 185 to 175 degrees clockwise, respectively.…”

FLASH instead of proton arc therapy is a more promising advancement for the next generation proton radiotherapy

“…A similar phenomenon was observed in the adoption of VMAT, even though there is no clear level 1 evidence of superior clinical benefits compared to the IMRT. 79 The effectiveness of the Linear Energy Transfer (LET) optimization via the arc trajectory not only spares the critical OARs from the high LET region but also increases the possibility of LET escalation in the tumor center where the radiation-resistant tumor cells (hypoxic) are usually located. 80 This feature would be critical for carbon arc therapy, where the RBE calculation is based on the LET.…”