BACKGROUND AND PURPOSE: The aim was to evaluate the spacer dimensions and prostate position variability during the course of radiotherapy for prostate cancer. MATERIALS AND METHODS: CT scans were performed in a group of 15 patients (G1) after the 10 ml injection of a hydrogel spacer (SpaceOAR™) and 30 patients without a spacer (G2) before the beginning of treatment (CT1) and in the last treatment week, 10-12 weeks following spacer implantation (CT2). Spacer dimensions and displacements were determined and prostate displacements compared. RESULTS: Mean volume of the hydrogel increased slightly (17%; p<0.01), in 4 of 15 patients >2 cm(3). The average displacement of the hydrogel center of mass was 0.6mm (87%≤ 2.2mm), -0.6mm (100% ≤ 2.2mm) and 1.4mm (87% ≤ 4.3mm) in the x-, y- and z-axes (not significant). The average distance between prostate and anterior rectal wall before/at the end of radiotherapy was 1.6 cm/1.5 cm, 1.2 cm/1.3 cm and 1.0 cm/1.1cm at the level of the base, middle and apex (G1). Prostate position variations were similar comparing G1 and G2, but significant systematic posterior displacements were only found in G2. CONCLUSIONS: A stable distance between the prostate and anterior rectal wall results during the radiotherapy course after injection of the spacer before treatment planning. Larger posterior prostate displacements could be reduced.
BACKGROUND AND PURPOSE: The aim was to evaluate the spacer dimensions and prostate position variability during the course of radiotherapy for prostate cancer. MATERIALS AND METHODS: CT scans were performed in a group of 15 patients (G1) after the 10 ml injection of a hydrogel spacer (SpaceOAR™) and 30 patients without a spacer (G2) before the beginning of treatment (CT1) and in the last treatment week, 10-12 weeks following spacer implantation (CT2). Spacer dimensions and displacements were determined and prostate displacements compared. RESULTS: Mean volume of the hydrogel increased slightly (17%; p<0.01), in 4 of 15 patients >2 cm(3). The average displacement of the hydrogel center of mass was 0.6mm (87%≤ 2.2mm), -0.6mm (100% ≤ 2.2mm) and 1.4mm (87% ≤ 4.3mm) in the x-, y- and z-axes (not significant). The average distance between prostate and anterior rectal wall before/at the end of radiotherapy was 1.6 cm/1.5 cm, 1.2 cm/1.3 cm and 1.0 cm/1.1cm at the level of the base, middle and apex (G1). Prostate position variations were similar comparing G1 and G2, but significant systematic posterior displacements were only found in G2. CONCLUSIONS: A stable distance between the prostate and anterior rectal wall results during the radiotherapy course after injection of the spacer before treatment planning. Larger posterior prostate displacements could be reduced.
Authors: Avani D Rao; Ziwei Feng; Eun Ji Shin; Jin He; Kevin M Waters; Stephanie Coquia; Robert DeJong; Lauren M Rosati; Lin Su; Dengwang Li; Juan Jackson; Stephen Clark; Jeffrey Schultz; Danielle Hutchings; Seong-Hun Kim; Ralph H Hruban; Theodore L DeWeese; John Wong; Amol Narang; Joseph M Herman; Kai Ding Journal: Int J Radiat Oncol Biol Phys Date: 2017-08-14 Impact factor: 7.038
Authors: M E Schutzer; P F Orio; M C Biagioli; D A Asher; H Lomas; D Moghanaki Journal: Prostate Cancer Prostatic Dis Date: 2015-02-17 Impact factor: 5.554
Authors: Ziwei Feng; Avani D Rao; Zhi Cheng; Eun Ji Shin; Joseph Moore; Lin Su; Seong-Hun Kim; John Wong; Amol Narang; Joseph M Herman; Todd McNutt; Dengwang Li; Kai Ding Journal: Int J Radiat Oncol Biol Phys Date: 2018-07-19 Impact factor: 7.038