演題抄録

International Session(Poster)

開催概要
開催回
第51回・2013年・京都
 

Stereotactic Body Radiotherapy for Low- and Intermediate Risk Prostate Cancers

演題番号 : ISP-28

[筆頭演者]
Bae-Kwon Jeong:1 
[共同演者]
In-Bong Ha:1、Hojin Jeong:1、Gyu-Young Chai:1、Ki-Mun Kang:1

1:Radiation Oncology, Gyeongsan National University, Korea

 

Purpose: Low a/b ratio of prostate cancer is radiobiologically rational with a hypofractionated radiotherapy regimen. This study was aimed to evaluate the efficacy and toxicity of hypofractionated stereotactic body radiotherapy (SBRT) using the CyberKnife for low and intermediate risk prostate cancers.Materials and Methods: Twenty-four patients with prostate cancer were retrospectively reviewed. All the patients were pathologically confirmed with the prostate cancer and received the hypofractionated SBRT. The CyberKnife was used for the hypofractionated SBRT with the fiducial tracking method. For each patient, planning CT and MRI scans were taken in the same day. Planning CT and MRI were coregistered with respect to each other for accurate identification of the target region. The CTV including the prostate and the proximal seminal vesicles, was first delineated on the coregistered CT/MRI images, and then expanded by 3 mm to posterior and by 5 mm to other directions to define PTV. The SBRT dose of 37.5 Gy in total was evenly delivered every other day to PTV with daily dose of 7.5 Gy over 5 fractions. Venous blood was obtained before and after SBRT for assay of the PSA level. Radiation-induced toxicity was evaluated according to the CTCAE, V4.03.Results: Median follow-up of 19.0 months. The median PSA level at diagnosis was 9.29 ng/mL. The PSA levels rapidly decreased at first 6 months after SBRT and then gradually declined later. The PSA bounce effect was observed in several patients. Two of them showed biochemical recurrence, but improved after salvage hormonal therapy. Acute side effects were generally mild (grades 1-2) and resolved. Only one patient experienced acute grade III toxicity (proctitis) even which was ameliorated shortly to grade II.Conclusion: The results so far showed that the CyberKnife-based SBRT is very effective to treat the low and intermediate risk prostate cancers with the good biochemical response and the acceptable toxicity.

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