Which Dosimetric Technique is Better; 3D-CRT, IMRT or VMAT in High Risk Prostate Cancer Treated by Hypofractionated radiotherapy with Elective Nodal Irradiation

Background: Prostate cancer is not common in Arab countries. In this study,
our aim is to investigate which dosimetric technique has better target coverage 
and organs sparing; 3D-CRT, IMRT or VMAT in high risk prostate cancer 
treated by hypofractionation with elective nodal irradiation. 
Patients and Methods: The medical records of five patients of high risk 
prostate cancer treated by VMAT were reviewed and re-planned by 3D-CRT & 
IMRT. PTV70 is covering the prostate and seminal vesicle while PTV50.4 is 
covering the prostate, seminal vesicle and local lymph nodes drainage. 
Contouring of organs at risks was done according to RTOG guidelines. 3D-CRT 
was delivered in two phases while IMRT and VMAT were delivered in one 
phase using simultaneous integrated boost. Target coverage, organs at risks 
sparing and treatment time beam on were compared between all plans. 
Results: All techniques had similar high dose target volume coverage (PTV70) 
while 3D-CRT had suboptimal coverage regarding to low dose target coverage 
(PTV50.4). OAR sparing was better and statistically significant in IMRT & 
VMAT while 3D-CRT failed to achieve the desired organs at risks sparing. 3D-
CRT had statistically significant better lower integral dose than IMRT & 
VMAT. Treatment time beam on is the shortest in VMAT while longer in IMRT 
and medium in 3D-CRT.
Conclusion: VMAT and IMRT techniques have optimal target coverage and 
organs sparing in case of high risk prostate cancer treated by hypofractionated 
irradiation using simultaneous elective nodal irradiation while 3D-CRT 
technique has suboptimal target coverage and organs sparing which make it 
unsuitable technique for such cases.