Biochemical Outcomes Following Prostate Brachytherapy with 5-year Minimum Follow-up: The Importance of Patient Selection and Implant Quality
Reviewer: William Levin, MD
Last Modified: October 7, 2002
Presenter: M.A. Kollmeier Presenter's Affiliation: Mount Sinai School of Medicine, New York Type of Session: Scientific
One form of radiation therapy used in the treatment of prostate cancer is brachytherapy.
The use of this technique is relatively new, compared to standard external beam therapy.
Accordingly, clinicians are still trying to uncover which factors are most imortant in determining the outcome in patients undergoing this procedure.
Materials and Methods
This was a retrospective analysis of 243 patients with clinically localized prostate cancer who were treated with permanent radioactive seed implantation (I-125 or Pd-103).
Patients were stratified into risk groups (low, intermediate, or high) based on PSA, stage, and Gleason score (GS).
Median follow-up was 68 months (49-84)
Median pre-treatment PSA was 8.2 (1.3-189)
78% of patients had a GS less than or equal to 6.
49% of patients were stage T2a or less, and 51% were T2b-T2c.
138 patients received I-125 and 105 patients received Pd-103 seeds.
At least 40% of patients got some form of hormal therapy.
Implant dose was defined as the D90 or dose delivered to 90% of the prostate volume on post-implant dosimetry.
Based on prior studies, patients were grouped into having either optimal or suboptimal D90.
Biochemical failure was defined using the ASTRO definition, 3 consecutive rises of PSA.
8-year actuarial freedom from biochemical failure (bFFF) was as follows: 80% for PSA < or equal to 10 ng/ml, 86% for PSA 10.1-20, 45% for PSA >20 (p=0.0001)
8-year bFFF was 85% for GS < or = to 6, versus 61% for GS > or = to 7.
8-y bFFF for the low risk group (T2a or less, GS 6 or less, inital PSA of 10 or less) was 88%, versus 65% for the high risk group (GS 8 or greater, or PSA 20 or higher, or at least 2 of the intermediate risk features.
Optimal dose implants (140 Gy or higher for I-125 and 100 Gy or higher for Pd-103) had an 8-y bFFF of 82%, versus 68% for suboptimal implants.
Hormonal therapy had no significant effect on outcome.
In multivariate analysis, statistically significant factors included: initial PSA, Gleason score, and dose group.
Low risk patients with optimal dose had a 5 year bFFF of 94%.
The optimal candidates for prostate brachytherapy should be those patients with the low risk group features.
5 year freedom from bichemical failure is excellent in this patient population.
This study, which was done at an institution known for excellence in the field of prostate brachytherapy, helps define who is a reasonable candidate for this treatment.
Although the results for the low risk group are excellent, longer follow-up is needed to confirm efficacy.
This study also underscores the importance of proper technique and dosing.
Oncolink's ASTRO Coverage made possible by an unrestricted Educational Grant from Ortho Biotech.
Oct 22, 2012 - For men with high-risk prostate cancer, postoperative radiation after radical prostatectomy is associated with improved biochemical progression-free survival over a median of 10.6 years of follow-up, compared with a wait-and-see policy, according to a study published online Oct. 19 in The Lancet.