NYPI PUBLICATIONS
A Multicenter study demonstrating discordant results from electronic prostate-specific antigen biochemical failure calculation systems.
- Williams SG, Pickles T, Kestin L, Potters L, Fearn P, Smith R, Pratt G. Peter MacCallum Cancer Centre and University of Melbourne, Melbourne, Australia.
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Permanent prostate brachytherapy: a century of technical evolution.
- Acher PL, Morris SL, Popert RJ, Perry MJ, Potters L, Beaney RP. Guy's and St Thomas' NHS Foundation Trust, London, UK.
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Permanent prostate brachytherapy: Dosimetric results and analysis of a learning curve with a dynamic dose-feedback technique.
- Acher P, Popert R, Nichol J, Potters L, Morris S, Beaney R. Department of Urology, Guy's & St. Thomas' NHS Foundation Trust, London, UK.
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Is there a Role for Post-Implant Dosimetry following Real-Time Dynamic Permanent Prostate Brachytherapy?
- Potters L, Calugaru E, Jassal A, Mullen EE, Presser J
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Long-term Multi-institutional Analysis of Stage T1T2 Prostate Cancer Treated with Permanent Brachytherapy
- M.J. Zelefsky, D.A. Kuban, L.B. Levy, L. Potters, D.C. Beyer, J.C. Blasko, B.J. Moran, J.P. Ciezki, A.L. Zietman,
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Purpose/Objective(s): To assess biochemical failure definitions (BFD) and long-term prostate-specific antigen (PSA) outcome after permanent prostate brachytherapy (BT) combined with external beam radiation treatment (EBRT) for patients (pts) with T1-T2 prostate cancer.
Materials/Methods: Eleven institutions combined data on 527 pts treated with combination of EBRT and BT and 2693 pts treated with BT monotherapy, the latter being used as a comparative group. Criteria for inclusion were: stage T1-T2, pre-treatment PSA, therapy 5 years before data collection (1988-1998), and no androgen suppression prior to failure. Prognostic groups were defined according to the National Comprehensive Cancer Network. Based on our prior work, multiple candidate PSA failure definitions appropriate for EBRT and BT alone were tested on the BT _ EBRT group for their ability to predict clinical failure.
Results: Median follow-up was 4.7 years for EBRT _ BT pts and 5.2 years for BT alone pts. 31% of EBRT _ BT pts were implanted with I-125 at a median dose of 120 Gy and 69% were treated with Pd-103 at a median dose of 90 Gy. BT doses were all pre TG-43. Median dose for EBRT was 45 Gy. 68% of BT only pts were implanted with I-125 at a median dose of 160 Gy and the remainder with Pd-103 at a median dose of 120 Gy. On regression analysis, similar to EBRT and permanent prostate brachytherapy alone, the nadir _2 ng/ml PSA failure definition fit the data best, with sensitivity and specificity of 65% and 91% versus 32% and 95% for 3 consecutive PSA rises (ASTRO without backdating). The surgical type definitions, such as an absolute PSA level of 0.2 ng/ml or 0.5 ng/ml, had high sensitivities but low specificities, although specificities were better than when using those definitions for external beam or brachytherapy alone. Using nadir _ 2 ng/ml failure definition, 7-year freedom from PSA failure was 93%, 75% and 50% for patients with low, intermediate and high risk disease, respectively. For low risk patients treated with BT alone and D90s _/_ 140 Gy for I-125 and _/_ 105 Gy for Pd-103, 7-year PSA disease-free survival (PSADFS) was 90% and 87% respectively, and not significantly different from pts treated with EBRT _ BT. For the intermediate risk group, multivariate analysis showed that stage, Gleason score, PSA, and treatment year were significant variables, but not isotope nor treatment (EBRT _ BT vs BT alone). Since the hazard ratio for PSA failure is slightly higher (1.2) for BT alone and the intermediate risk group is somewhat heterogeneous, further analysis of particular subgroups is necessary as is the effect of D90. High risk patients did poorly with either treatment method.
Conclusions: The current nadir _ 2 ng/ml biochemical failure definition is well suited to patients treated with EBRT _ BT, and therefore, this BFD provides a uniform method to assess biochemical failures in pts treated with EBRT and/or BT. In patients with minimum follow-up _/_ 5-6 years, defining biochemical failure as exceeding an absolute PSA level of 0.5 ng/ml may be reasonable. While low risk patients did equally as well with brachytherapy alone, and high risk patients did poorly with either treatment method, whether supplemental external beam radiation is beneficial for the intermediate risk group, or perhaps certain subgroups, may be best answered by a randomized trial
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