Comparison of VMAT and IMRT strategies for cervical cancer patients using automated planning.
OBJECTIVE
In a published study on cervical cancer, 5-beam IMRT was inferior to single arc VMAT. Here we compare 9, 12, and 20 beam IMRT with single and dual arc VMAT.


METHODS
For each of 10 patients, automated plan generation with the in-house Erasmus-iCycle optimizer was used to assist an expert planner in generating the five plans with the clinical TPS.


RESULTS
For each patient, all plans were clinically acceptable with a high and similar PTV coverage. OAR sparing increased when going from 9 to 12 to 20 IMRT beams, and from single to dual arc VMAT. For all patients, 12 and 20 beam IMRT were superior to single and dual arc VMAT, with substantial variations in gain among the study patients. As expected, delivery of VMAT plans was significantly faster than delivery of IMRT plans.


CONCLUSIONS
Often reported increased plan quality for VMAT compared to IMRT has not been observed for cervical cancer. Twenty and 12 beam IMRT plans had a higher quality than single and dual arc VMAT. For individual patients, the optimal delivery technique depends on a complex trade-off between plan quality and treatment time that may change with introduction of faster delivery systems.
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands. Electronic address: a.sharfo@erasmusmc.nl.
Abdul Wahab M
AW
Sharfo
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands.
Peter W J
PW
Voet
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands.
Sebastiaan
S
Breedveld
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands.
Jan Willem M
JW
Mens
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands.
Mischa S
MS
Hoogeman
Department of Radiation Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands.
Ben J M
BJ
Heijmen
D001331:Automation; D005260:Female; D006801:Humans; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D013997:Time Factors; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
Automated knowledge-based planning; IMRT; Locally advanced cervical cancer; VMAT