Re-distribution of brachytherapy dose using a differential dose prescription adapted to risk of local failure in low-risk prostate cancer patients. Issue 3 (June 2015)

• Record Type: Journal Article
• Authors: Rylander, Susanne; Polders, Daniel; Steggerda, Marcel J.; Moonen, Luc M.; Tanderup, Kari; Van der Heide, Uulke A.
• Is Part Of: Radiotherapy and oncology. Volume 115:Issue 3(2015:Jun.)
• Page Start: 308
• Page End: 313
• Publication Date: 2015-06
• Subjects: Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2015.05.015
• Languages: English
• ISSNs: 0167-8140

Abstract

<abstract xml:lang="en" abstract-type="author" id="ab005"> <title id="st005">Abstract</title> <sec> <title id="st010">Background and purpose</title> <p id="sp0005">We investigated the application of a differential target- and dose prescription concept for low-dose-rate prostate brachytherapy (LDR-BT), involving a re-distribution of dose according to risk of local failure and treatment-related morbidity.</p> </sec> <sec> <title id="st015">Material and methods</title> <p id="sp0010">Our study included 15 patients. Multi-parametric MRI was acquired prior to LDR-BT for gross tumor volume (GTV) delineation. Trans-rectal ultrasound (US) images were acquired during LDR-BT for prostate gland- (CTV<sub>Prostate</sub>) and organs at risk delineation. The GTV contour was transferred to US images after US/MRI registration. An intermediate-risk target volume (CTV<sub>Prostate</sub>) and a high-risk target volume (CTV<sub>HR</sub> = GTV + 5 mm margin) were defined. Two virtual dose plans were made: Plan<sub>risk-adapt</sub> consisted of a de-escalated dose of minimum 125 Gy to the CTV<sub>Prostate</sub> and an escalated dose to 145–250 Gy to the CTV<sub>HR</sub>; Plan<sub>ref</sub> included the standard clinical dose of minimum 145 Gy to the CTV<sub>Prostate</sub>. Dose-volume-histogram (DVH) parameters were expressed in equivalent 2 Gy fractionation doses.</p> </sec> <sec> <title id="st020">Results</title> <p id="sp0015">The median D<sub>90%</sub> to the GTV and CTV<sub>HR</sub> significantly increased by 44 Gy and 17 Gy, respectively when comparing Plan<sub>risk-adapt</sub> to Plan<sub>ref</sub>. The median D<sub>10%</sub> and D<sub>30%</sub> to the urethra significantly decreased by 9 Gy and 11 Gy, respectively and for bladder neck by 18 Gy and 15 Gy, respectively. The median rectal D<sub>2.0 cm<sup>3</sup></sub> had a significant decrease of 4 Gy, while the median rectal D<sub>0.1 cm<sup>3</sup></sub> showed an increase of 1 Gy.</p> </sec> <sec> <title id="st025">Conclusions</title> <p id="sp0020">Our risk adaptive target- and dose prescription concept of prescribing a lower dose to the whole gland and an escalated dose to the GTV using LDR-BT seed planning was technically feasible and resulted in a significant dose-reduction to urethra and bladder neck.</p> </sec> </abstract>