Prostate Cancer Journal
Impact of Percentage of Positive Biopsy Cores on
Biochemical Outcome in Patients Treated With Low-Dose Rate
(Iodine-125) Brachytherapy for Prostate Cancer
C. Yuen, T. Hossack, A.M. Haynes, R.A. Pe Benito, J. Matthews,
G. Fogarty, R. Jagavkar, P. Brenner and P. Stricker
• To investigate the significance of the percentage of
positive biopsy cores (PPBCs) in predicting the biochemical
outcome in patients with clinically localised prostate
cancer undergoing low-dose rate brachytherapy (LDRB).
• A total of 326 consecutive patients underwent LDRB between February 1997
and January 2007. The cohort consisted of 68.7%, 30.4% and
0.9% of low-, intermediate- and high-risk groups
respectively as defined by the D'Amico classification.
Patients were stratified according to PPBCs (<35%, 35-50%,
• Of the 326 men, 316 (97%) met the study criteria and
were included in the analysis. The median follow-up was 66.3
(12.9-147.5) months. Thirty-eight men (12%) developed
evidence of biochemical relapse as defined by the Phoenix
definition at a median of 44.5 (4-133) months. The overall
5-year and 10-year biochemical relapse-free rate (BRFR) was
91.9% (95% CI 87.9% to 94.6%) and 76.9% (95% CI 66% to 84%)
• On univariate analysis, Gleason score (p=0.03), D'Amico risk groups
(p=0.004) and PPBCs (p=0.001) were significant predictors of
biochemical failure. In the multivariate model, the PPBCs
(p=0.0006) and pretreatment PSA (p=0.004) were the only
variables that predicted for biochemical failure. The 5-year
biochemical relapse-free rate was 93.5%, 93.0% and 76.5% for
the PPBCs <35%, 35%-50% and >50% respectively (p=0.001).
• The PPBC is an important independent predictor of the
5-year biochemical relapse-free survival after LDRB. This
finding suggests that patients with high volume tumour are
at increased risk of biochemical failure with LDRB.