Long-Term Outcome by Risk Factors Using Conformal High Dose Rate Boost for Prostate Cancer
Reviewer: William Levin, MD
Last Modified: October 8, 2002
Presenter: R. Galalae
Presenter's Affiliation: Dept. of Radiation Oncology, Kiel University, Germany
Type of Session: Scientific
- Radiation therapy is widely used in the treatment of prostate cancer. Forms of this treatment include external beam radiation or brachytherapy, or a combination of the two. With brachytherapy, radioactive seeds are implanted into the prostate gland.
- Until recently, the radioactive seeds have remained permanently implanted, giving off energy slowly over time.
- Now comes a new technology, high dose rate brachytherapy (HDRB) whereby very powerful radioactive sources are put into the prostate, via catheters, for only several minutes at a time.
- This current study reviews the results of the prostate HDRB experience from some of the most well known brachytherapy institutions in the world.
Materials and Methods
- This is an analysis of 3 separate trials involving a total of 611 patients with clinically localized prostate cancer.
- All patients initially received external beam radiation therapy (EBRT) followed by dose-escalating HDRB.
- For analysis, patients were stratified in to risk groups (based on commonly accepted criteria, including, Gleason score (GS), PSA, and clinical stage).
- The endpoint was PSA failure, based on the ATRO definition.
- Mean follow-up was 5 years (0.2-15.3)
- For the 611 patients, biochemical control (BC) at 5 and 10 years were 77% and 73%, respectively. Disease free survival was 67% and 49%.
- Group I patients (stage< T2a, GS< 6, PSA<10) had BC of 96%.
- Group II patients (stage> T2b, GS> 7, PSA> 10, any one factor) had BC of 87% without hormone therapy and 91% with hormone therapy.
- Group III patients (2 or more risk factors described in group II) had BC of 97% without hormone therapy and 90% with hormones.
- For groups II & III, regression analysis identified pre-treatment PSA, stage, and Gleason score as predictive for biochemical failure, while the use of hormones was not.
- EBRT in combination with high dose rate brachytherapy produced excellent results with regard to biochemical control, even in the group III patients.
- The authors also pointed out that these results were all similar between the 3 contributing institutions, highlighting the reproducibility of the findings.
- This article suggests that HDRB may be efficacious in the treatment of early-stage prostate cancer.
- The authors point out that they are still in the process of determining the optimal dose for HDRB.
- Although these findings are encouraging, much longer follow-up is needed to see if the results are equivalent to standard, well established therapies.
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