- 作者：Olivier Chapet ; Corina Udrescu ; Ronan Tanguy ; Alain Ruffion ; Pascal Fenoglietto ; Marie-Pierre Sotton ; Marian Devonec ; Marc Colombel ; Patrice Jalade ; David Azria
- 刊名：International Journal of Radiation Oncology*Biology*Physics
- 出版年：1 February, 2014
- 年：2014
- 卷：88
- 期：2
- 页码：425-432
- 全文大小：1156 K
Purpose
This study assessed the contribution of ahyaluronic acid (HA) injection between the rectum and the prostate to reducing the dose to the rectal wall in stereotactic body radiation therapy (SBRT).Methods and Materials
As part of a phase 2 study of hypofractionated radiation therapy (62聽Gy in 20 fractions), the patients received a transperineal injection of 10 cc HA between the rectum and the prostate. A dosimetric computed tomographic (CT) scan was systematically performed before (CT1) and after (CT2) the injection. Two 9-beam intensity modulated radiation therapy-SBRT plans were optimized for the first 10 patients on both CTs according to 2 dosage levels:聽5聽脳聽6.5聽Gy (PlanA) and 5聽脳聽8.5聽Gy (PlanB). Rectal wall parameters were compared with a dose-volume histogram, and the prostate-rectum separation was measured at 7 levels of the prostate on the center line of the organ.
Results
For both plans, the average volume of the rectal wall receiving the 90% isodose line (V90%) was reduced up to 90% after injection. There was no significant difference (P=.32) between doses received by the rectal wall on CT1 and CT2 at the base of the prostate. This variation became significant from the median plane to the apex of the prostate (P=.002). No significant differences were found between PlanA without HA and PlanB with HA for each level of the prostate (P=.77, at the isocenter of the prostate).
Conclusions
HA injection significantly reduced the dose to the rectal wall and allowed a dose escalation from 6.5聽Gy to 8.5聽Gy without increasing the dose to the rectum. A phase 2 study is under way in our department to assess the rate of acute and late rectal toxicities when SBRT (5聽脳聽8.5聽Gy) is combined with an injection of HA.