Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer: a planning study.
BACKGROUND
Compared to static beam Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-independent comparison of radiotherapy treatment planning of IMRT and VMAT for head-and-neck cancer performed by several institutes and based on the same CT- and contouring data.


METHODS
Five institutes generated IMRT and VMAT plans for five oropharyngeal cancer patients using either Pinnacle3 or Oncentra Masterplan to be delivered on Elekta linear accelerators.


RESULTS
Comparison of VMAT and IMRT plans within the same patient and institute showed significantly better sparing for almost all OARs with VMAT. The average mean dose to the parotid glands and oral cavity was reduced from 27.2 Gy and 39.4 Gy for IMRT to 25.0 Gy and 36.7 Gy for VMAT, respectively. The dose conformity at 95% of the prescribed dose for PTVboost and PTVtotal was 1.45 and 1.62 for IMRT and 1.37 and 1.50 for VMAT, respectively. The average effective delivery time was reduced from 13:15 min for IMRT to 5:54 min for VMAT.


CONCLUSIONS
Independently of institution-specific optimization strategies, the quality of the VMAT plans including double arcs was superior to step-and-shoot IMRT plans including 5-9 beam ports, while the effective treatment delivery time was shortened by ~50% with VMAT.
Department of Radiation Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, Amsterdam, CX 1066, The Netherlands.
Andrea
A
Holt
Dirk
D
Van Gestel
Mark P
MP
Arends
Erik W
EW
Korevaar
Danny
D
Schuring
Martina C
MC
Kunze-Busch
Rob Jw
RJ
Louwe
Corine
C
van Vliet-Vroegindeweij
D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D009959:Oropharyngeal Neoplasms / Q000532:radiotherapy*; D011379:Prognosis; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies