Pinkawa M, Corral NE, Caffaro M, Piroth MD, Holy R, Djukic V, Otto G, Schoth F, Eble MJ. Application of a spacer gel to optimize three-dimensional conformal and intensity modulated radiotherapy for prostate cancer.
Radiother Oncol 2011;
100:436-41. [PMID:
21963289 DOI:
10.1016/j.radonc.2011.09.005]
[Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 09/06/2011] [Accepted: 09/10/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE
The aim was to evaluate the impact of a spacer gel on the dose distribution, applying three-dimensional conformal (3D CRT) and intensity modulated radiotherapy (IMRT) planning techniques.
MATERIAL AND METHODS
The injection of a spacer gel (10 ml SpaceOAR™) was performed between the prostate and rectum under transrectal ultrasound guidance in 18 patients with prostate cancer. 3D CRT and IMRT treatment plans were compared based on CT before and after injection (78 Gy prescription dose).
RESULTS
In contrast to the PTV and bladder, significant advantages (p<0.01) resulted in respect of all analysed rectal dose values comparing pre spacer with post spacer plans for both techniques. Rectal NTCP (normal tissue complication probability) reached the lowest percentage after spacer injection irrespective of the technique, with a mean reduction of >50% for both IMRT and 3D CRT. Significantly (p<0.01) higher D(mean), and V(78) for the PTV were reached with IMRT vs. 3D CRT plans, with a smaller rectum V(76) but larger rectum V(50).
CONCLUSIONS
The injection of a spacer gel between the prostate and anterior rectal wall is associated with considerably lower doses to the rectum and consequentially lower NTCP values irrespective of the radiotherapy technique.
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