Local Control Following Permanent Prostate Brachytherapy: Effect of High Biologically Effective Dose on Biopsy Results and Oncologic Outcomes

Stone, Nelson N.; Stock, Richard G.; Cesaretti, Jamie A.; Unger, Pam

doi:10.1016/j.ijrobp.2009.01.078

Cited by 93 publications

(73 citation statements)

References 25 publications

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“…Prostate BT with a permanent I-125 implant has been established as an effective treatment for localized prostate cancer because of the minimal invasiveness and good outcomes. Recently, with increasing doses delivered to the prostate and its effective combination with external beam radiation therapy (EBRT) or hormone therapy, the outcome of prostate BT has improved in patients with low-, intermediate- and even high-risk localized prostate cancer [3,4,5,6,7,8]. Concerning the combination of hormone therapy with EBRT, the positive impacts of hormone therapy for intermediate- and high-risk prostate cancer have been established in several prospective, randomized, clinical trials [9,10].…”

Section: Introductionmentioning

confidence: 99%

Clinical Significance of Neoadjuvant Combined Androgen Blockade for More Than Six Months in Patients with Localized Prostate Cancer Treated with Prostate Brachytherapy

Senzaki¹,

Fukumori²,

Mori³

et al. 2015

Urol Int

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Introduction: The aim of this study is to clarify the clinical significance of neoadjuvant combined androgen blockade (CAB) for ≥6 months in patients with localized prostate cancer. Patients and Methods: A total of 431 patients with localized prostate cancer who underwent prostate brachytherapy (BT) with or without neoadjuvant CAB for ≥6 months with mean follow-up time of 64.6 months (range 24-108 months) were evaluated retrospectively. Of those 431, 232 patients received BT in combination with neoadjuvant CAB for ≥6 months. Biochemical recurrence-free rates (BRFRs) in 364 patients with at least 3 years of follow-up were evaluated by log-rank test. Results: BRFR in patients with low-, intermediate- and high-risk prostate cancer were 98.1, 94.2 and 89.1%, respectively. In patients with intermediate-risk prostate cancer only, neoadjuvant CAB was significantly associated with BRFR (p = 0.0468). Especially in patients with intermediate-risk prostate cancer with radiation dose received by 90% of the prostate (D90) <180 Gy, neoadjuvant CAB exerted a favorable impact on BRFR (p = 0.0429). On multivariate analyses, neoadjuvant CAB and D90 were independent predictors of BRFR (p = 0.0061 and p < 0.0001, respectively). Conclusions: Neoadjuvant CAB for ≥6 months has a favorable impact on BRFR in patients with intermediate-risk prostate cancer, particularly in patients with relatively low radiation doses of D90.

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Section: Introductionmentioning

confidence: 99%

Clinical Significance of Neoadjuvant Combined Androgen Blockade for More Than Six Months in Patients with Localized Prostate Cancer Treated with Prostate Brachytherapy

Senzaki¹,

Fukumori²,

Mori³

et al. 2015

Urol Int

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“…27,28 Larger outcomes studies from other institutions 29-33 report 5-10 yr biochemical failure-free survival rates for similar low to intermediate risk PIPB patients generally in the range of 85-95%. Indeed, investigators 7,8,9 have correlated low BED values to poor clinical outcomes, but modeling approaches adopted for those investigations are most similar to BED NR using TG43sim which we have found to be proportional to D 90 and to be the highest estimate of biological dose which yields a TCP of at least 90% for 95% of patients. This suggests a needed to reassess radiobiological model parameter values when coupling heterogeneous tissue model-based dose calculations, such that cohort-average radiobiological model predictions align with clinical observation.…”

Section: A Model-based Dose Calculations Compared With Tg-43mentioning

confidence: 89%

Coupling I‐125 permanent implant prostate brachytherapy Monte Carlo dose calculations with radiobiological models

et al. 2017

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Purpose: To investigate the coupling of radiobiological models with patient-specific Monte Carlo (MC) dose calculations for permanent implant prostate brachytherapy (PIPB). To compare radiobiological indices evaluated with different radiobiological models using MC and simulated AAPM TG-43 dose calculations. Methods: Three-dimensional dose distributions previously computed using MC techniques with two types of patient models, TG43sim (AAPM TG-43 water-based conditions) and MCDmm (realistic tissues and interseed effects), for 613 PIPB patients are coupled with biological dose and tumour control probability (TCP) models. Two approaches and their extensions are considered to evaluate biological doses, biologically effective dose (BED) and isoeffective dose (IED), as well as two methods to evaluate TCP. Three novel extensions of equivalent uniform biologically effective dose (EUBED) are suggested which consider the spatial distribution of doses within the target volume. Adopted radiobiological model parameter values (a, b, etc) are those suggested by AAPM TG-137, and sensitivity to parameter choice is discussed. Results: MCDmm dose calculations can reveal low doses in the prostate target volume, due to tissue heterogeneities or inter-seed effects; considering these low doses in EUBED calculations can lower TCP estimates by up to 70%, with largest differences in patients with calcifications. There are large variations in biological doses and TCPs evaluated over the 613 patient cohort for each radiobiological model considered, reflecting the spectrum of physical doses calculated for these patients with either MCDmm or TG43sim. Depending on the model details, BED, IED and EUBED are, on average, 6.0-9.8%, 7.4-9.2% and 1.8-15% higher, respectively, with TG43sim than MCDmm. TCP estimates computed using MCDmm dose distributions are much lower than expected based on past treatment outcome studies, suggesting a need to re-assess model parameters when evaluating radiobiological indices coupled with heterogeneous tissue model-based dose calculations. Conclusions: Cohort average differences in biological dose and TCP estimates between radiobiological models are generally larger than differences for any one radiobiological model evaluated with TG43sim or MCDmm dose calculations. However, heterogeneous tissue dose calculations, like MCDmm, can identify clinically-relevant low dose volumes, e.g., in patients with calcifications, which would otherwise be missed with TG-43. In addition to affecting physical dose distributions, these low dose volumes can largely impact radiobiological dose and TCP estimates, which further motivates the clinical implementation of model-based dose calculations for PIPB.

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“…The combination of high-dose-rate (HDR) brachytherapy and external irradiation is an effective treatment for delivering radiation doses more precisely in prostate cancer, even if patients have extracapsular invasion and seminal vesicle invasion [3][4][5]. Technical modifications for prostate brachytherapy are being developed to obtain the better treatment outcome [2,[7][8][9][10]. However, approximately 5%-20% of those patients, as it now stands, show recurrence within 5 years after brachytherapy [1,2,5,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Technical modifications for prostate brachytherapy are being developed to obtain the better treatment outcome [2,[7][8][9][10]. However, approximately 5%-20% of those patients, as it now stands, show recurrence within 5 years after brachytherapy [1,2,5,11,12].…”

Section: Introductionmentioning

confidence: 99%

Perioperative search for circulating tumor cells in patients undergoing prostate brachytherapy for clinically nonmetastatic prostate cancer

Tsumura¹,

Satoh²,

Tabata³

et al. 2017

European Urology Supplements

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Local Control Following Permanent Prostate Brachytherapy: Effect of High Biologically Effective Dose on Biopsy Results and Oncologic Outcomes

Cited by 93 publications

References 25 publications

Clinical Significance of Neoadjuvant Combined Androgen Blockade for More Than Six Months in Patients with Localized Prostate Cancer Treated with Prostate Brachytherapy

Clinical Significance of Neoadjuvant Combined Androgen Blockade for More Than Six Months in Patients with Localized Prostate Cancer Treated with Prostate Brachytherapy

Coupling I‐125 permanent implant prostate brachytherapy Monte Carlo dose calculations with radiobiological models

Perioperative search for circulating tumor cells in patients undergoing prostate brachytherapy for clinically nonmetastatic prostate cancer

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