Abstracts Archive

UK & Ireland Prostate Brachytherapy Conference 2011

Abstract number 7

Overview of 11 Years Experience in I-125 Prostate Brachytherapy.

Eliot Chadwick, Royal Surrey County Hospital
Robert W Laing, Royal Surrey County Hospital
Stephen EM Langley, Royal Surrey County Hospital

Aim: The 11 year experience of I-125 LDR prostate brachytherapy in a UK centre is described.

Methods: Between March 1999 and September 2010, over 1700 patients underwent prostate brachytherapy, either as monotherapy or in combination with external beam radiotherapy (EBRT) and neoadjuvant hormones (NAH). Data were recorded on a bespoke prospective database. Survival analyses were performed on patients treated at least 3 years ago (n=1113). Outcomes were analysed by MSKCC risk grouping, treatment modality, PSA nadir and dosimetry. Biochemical relapse free survival (bRFS) was measured by the nadir+2 definition.

Results: The mean age was 64.1 (44-83) years. Median PSA follow up was 48(0-134) months. bRFS at 8 years was 84%. bRFS at 8 years for low, intermediate and high risk disease were 87%, 84% and 75% respectively. The use of EBRT did not influence bRFS in any risk group. The use of hormone therapy did not influence bRFS in low and intermediate risk groups. No significant association was seen with a D90 threshold of 130 or 140Gy, and bRFS. PSA nadir >0.5 was associated with decreased bRFS (p<0.0001). Baseline PSA and Gleason score were significant predictors of failure (HR 1.7, p<0.05 for both). Clinical stage was not a predictor of failure.

Conclusions: PSA nadir is a strong predictor of biochemical failure whether or not NAH were used. Patients with high risk disease remain biochemically controlled beyond any influence of hormonal therapy by combining EBRT with BXT. Monotherapy can be offered to selected intermediate risk patients. A durable relapse-free survival has been achieved in all risk groups by careful consideration of treatment strategy when assessing patients.