الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Prostate cancer is among the most common cancers in men worldwide, with an estimated 1,600,000 cases and 366,000 deaths annually [1]. In the United States, there was an estimated 161,000 cases and 26,700 deaths in 2017 [2]. External beam radiotherapy (EBRT) is one of the standard treatment options for localized prostate cancer (PC; T1c-T2c N0M0), Combined with androgen-deprivation therapy (ADT) for 6 months-3 years, EBRT is also an established treatment option for locally advanced (T3-T4 N0M0) and high-risk prostate cancer defined as Gleason 8 or higher, prostate-specific antigen (PSA)>20 ng/mL, or both [3]. Intensity-modulated radiotherapy (IMRT), a further improvement of 3-dimensional conformal radiotherapy, is becoming the gold standard in EBRT because of its ability to safely provide higher doses to the prostate and seminal vesicles while lowering toxicity for the organs at risk (OAR) [4]. So IMRT has been a state-of-the-art radical radiotherapy technique in prostate cancer owing to its capability to deliver highly conformal radiation doses to the targets while minimising the irradiation to adjacent critical organs [5]. However, IMRT planning and quality assurance is more complex and time-consuming than 3D-CRT and requires more monitor units (MUs) and many fixed beams, which in turn leads to longer treatment times [5]. Recently, investigators have attempted to develop another novel Linac-based IMRT delivery system, volumetric modulated arc therapy, with less treatment time and fewer monitor units.