Re-distribution of brachytherapy dose using a differential dose prescription adapted to risk of local failure in low-risk prostate cancer patients.

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.

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- (CTVProstate) and organs at risk delineation. The GTV contour was transferred to US images after US/MRI registration. An intermediate-risk target volume (CTVProstate) and a high-risk target volume (CTVHR=GTV+5mm margin) were defined. Two virtual dose plans were made: Planrisk-adapt consisted of a de-escalated dose of minimum 125Gy to the CTVProstate and an escalated dose to 145-250Gy to the CTVHR; Planref included the standard clinical dose of minimum 145Gy to the CTVProstate. Dose-volume-histogram (DVH) parameters were expressed in equivalent 2Gy fractionation doses.

The median D90% to the GTV and CTVHR significantly increased by 44Gy and 17Gy, respectively when comparing Planrisk-adapt to Planref. The median D10% and D30% to the urethra significantly decreased by 9Gy and 11Gy, respectively and for bladder neck by 18Gy and 15Gy, respectively. The median rectal D2. 0cm(3) had a significant decrease of4Gy, while the median rectal D0. 1cm(3) showed an increase of 1Gy.

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.

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2015 Jun 16 [Epub]

Susanne Rylander, Daniel Polders, Marcel J Steggerda, Luc M Moonen, Kari Tanderup, Uulke A Van der Heide

Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.   Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. , Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. , Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. , Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Oncology, Aarhus University Hospital, Aarhus, Denmark. , Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.

PubMed

E-Newsletters

Newsletter subscription

Free Daily and Weekly newsletters offered by content of interest

The fields of GU Oncology and Urology are rapidly advancing. Sign up today for articles, videos, conference highlights and abstracts from peer-review publications by disease and condition delivered to your inbox and read on the go.

Subscribe