15-year Biochemical Relapse-Free Survival and Overall Survival Following 125I Prostate Brachytherapy in Clinically Localized Prostate Cancer: Seattle Experience

Accepted for future publication of the 51st ASTRO Annual Meeting Nov. 1-5, 2009
Author block: J. E. Sylvester1,2, P. D. Grimm1,2, J. Wong1,2, R. W. Galbreath3, J. A. Khanjian1, G. S. Merrick4, J. C. Blasko5
1Seattle Prostate Cancer Center, Seattle, WA, 2Swedish Medical Center, Seattle, WA, 3Wheeling Jesuit University, Wheeling, WV, 4Schiffler Cancer Center, Wheeling, WV, 5Retired, -, WA

Purpose: To report the 15-year biochemical relapse-free survival (BRFS), and overall survival (OS) outcomes in a tight cohort of patients treated, early in the Seattle experience, with 125I brachytherapy for clinically localized prostate cancer.

Methods and Materials: Two hundred and fifteen patients with clinically localized prostate cancer were consecutively treated with 125I monotherapy from 1988-1992. Of these, one hundred seventy three patients have a minimum follow-up of 3.6 years and make up this study cohort. None received androgen ablation therapy or external beam radiation therapy. They were evaluated for BRFS and OS. Multivariate analysis was used to evaluate outcomes by pretreatment clinical prognostic factors. BRFS was analyzed by the Phoenix (nadir+2ng/ml) definition. OS was evaluated by chart review, death certificates and referring physician follow-up notes. Gleason scoring was performed by general pathologists at a community hospital in Seattle. Time to biochemical failure (BF) was calculated and compared by Kaplan-Meier plots.

Results: The fifteen-year BRFS for the entire cohort was 80.4%. There were 128 low risk, 36 intermediate risk and 9 high risk patients by D’Amico risk group classification. The 15 year biochemical control rate was 85.7% for low, 83.6% for intermediate and 79.3% for high risk patients. Overall median follow-up was 11.7 years. Follow-up ranged from 3.6 years to 18.4 years. Median follow-up was 15.4 years for patients alive and biochemically no evidence of disease (bNED). The median time to BF in those that failed was 5.1 years. The mean and median post-treatment PSA was 0.1ng/ml in the bNED patients. Average age at time of treatment was 70 years old. OS was 37.1%. There was no significant difference in BRFS between risk groups.

Conclusion: I125 monotherapy results in excellent 15-year BRFS, especially when the era of treatment is taken into account. Overall survival was equivalent to age matched normal population during that era.