Dosimetric comparison of intensity-modulated fractional radiotherapy and stereotactic body radiotherapy in low-risk prostate cancer

In radiotherapy (RT) applications, the main goal is to give the prescribed dose to the target volume, while protecting the surrounding healthy tissues and organs at risk as soon as possible. By developing technological skills and planning abilities, systems let us to apply volumetric and intensity modulated technics. Intensity-modulated RT (IMRT) has become the standard external RT (External Body Radiation Therapy-EBRT) application in the treatment of prostate cancer (PC) due to the advancement of radiological imaging and treatment planning systems (TPS), and treatment devices. In recent years, volumetric modulated arc therapy (VMAT) has been used in PC treatment to improve dose distributions. In addition, dose determination studies for PC have revealed that RT applied at high doses per fraction increases tumor control, and stereotactic body RT (SBRT) has been applied in order to increase these doses in PC treatment. In this study, 15 patients with a primary diagnosis of PC and treated in the Radiation Oncology Department of Karadeniz Technical University using conventional and SBRT fraction schemes, IMRT, and VMAT techniques, four different RT treatment planning technics for each patient (total 60 plans) and a dosimetric comparison of the treatment plans were made. Total dose prescribed for all patients is 78 gray (Gy) in 39 fractions for the conventional dose scheme, and 36.25 Gy in 5 fractions at for the SBRT scheme. The goal of the treatment plans is to deliver 95% of prescribed dose to the target volume, and reference organs at risk dose table is applicable for dose distribution. Dose values were obtained through dose volume histograms (DVH) of the created treatment plans, and statistical analyses were made using the SPSS version 13 program, Paired -T and Wilcoxon tests.