- 作者：Nelson N. Stone ; Richard G. Stock ; Jamie A. Cesaretti ; Pam Unger
- 刊名：International Journal of Radiation Oncology*Biology*Physics
- 出版年：2010
- 出版时间：1 February 2010
- 年：2010
- 卷：76
- 期：2
- 页码：355-360
- 全文大小：226 K
Purpose
To determine factors that influence local control and systemic relapse in patients undergoing permanent prostate brachytherapy (PPB).Methods and Materials
A total of 584 patients receiving PPB alone or PPB with external beam radiation therapy (19.5 % ) agreed to undergo prostate biopsy (PB) at 2 years postimplantion and yearly if results were positive or if the prostate-specific antigen (PSA) level increased. Short-term hormone therapy was used with 280 (47.9 % ) patients. Radiation doses were converted to biologically effective doses (BED) (using α/β = 2). Comparisons were made by chi-square analysis and linear regression. Survival was determined by the Kaplan-Meier method.
Results
The median PSA concentration was 7.1 ng/ml, and the median follow-up period was 7.1 years. PB results were positive for 48/584 (8.2 % ) patients. Positive biopsy results by BED group were as follows: 22/121 (18.2 % ) patients received a BED of ≤150 Gy; 15/244 (6.1 % ) patients received >150 to 200 Gy; and 6/193 (3.1 % ; p < 0.001) patients received >200 Gy. Significant associations of positive PB results by risk group were low-risk group BED (p = 0.019), intermediate-risk group hormone therapy (p = 0.011) and BED (p = 0.040), and high-risk group BED (p = 0.004). Biochemical freedom from failure rate at 7 years was 82.7 % . Biochemical freedom from failure rate by PB result was 84.7 % for negative results vs. 59.2 % for positive results (p < 0.001). Cox regression analysis revealed significant associations with BED (p = 0.038) and PB results (p = 0.002) in low-risk patients, with BED (p = 0.003) in intermediate-risk patients, and with Gleason score (p = 0.006), PSA level (p < 0.001), and PB result (p = 0.038) in high-risk patients. Fifty-three (9.1 % ) patients died, of which eight deaths were due to prostate cancer. Cause-specific survival was 99.2 % for negative PB results vs. 87.6 % for positive PB results (p < 0.001).
Conclusions
Higher radiation doses are required to achieve local control following PPB. A BED of >200 Gy with an α/β ratio of 2 yields 96.9 % local control rate. Failure to establish local control impacts survival.