Method to determine the nadir PSA following partial gland ablation

Abstract Objectives The objective of this study is to propose a novel method of determining the nadir PSA (nPSA) for men with prostate cancer treated by partial gland ablation (PGA). Materials and Methods Two cohorts of men were analyzed to develop a formula for the nPSA in men undergoing PGA. First...

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Main Authors: Nelson N. Stone, Vassilios Skouteris, Rendi Shu, Richard G. Stock, Ben GL Vanneste
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:BJUI Compass
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Online Access:https://doi.org/10.1002/bco2.496
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author Nelson N. Stone
Vassilios Skouteris
Rendi Shu
Richard G. Stock
Ben GL Vanneste
author_facet Nelson N. Stone
Vassilios Skouteris
Rendi Shu
Richard G. Stock
Ben GL Vanneste
author_sort Nelson N. Stone
collection DOAJ
description Abstract Objectives The objective of this study is to propose a novel method of determining the nadir PSA (nPSA) for men with prostate cancer treated by partial gland ablation (PGA). Materials and Methods Two cohorts of men were analyzed to develop a formula for the nPSA in men undergoing PGA. First, 123 men with a suspicion of prostate cancer underwent transperineal mapping biopsy (TPMB) and found to have benign pathology. Their prostate‐specific antigen (PSA) was compared to the prostate volume using curve estimation regression analysis. Second, the contribution of PSA from an ablated region was determined by using a surrogate of 545 men who had whole‐gland brachytherapy followed by prostate biopsy. Biopsy results were compared to radiation dose (calculated as the biological equivalent dose) levels in men who were free from biochemical failure. The nPSA was then calculated by using the PSA density (PSAD) for the untreated volume plus the PSA from the post‐brachytherapy patients. Results The PSAD with the highest R2 (0.80, p < 0.001) for the 123 men who had TPMB and a negative biopsy was 0.12 ng/mL2. In the brachytherapy patients, five 20 Gy dose groups were analyzed from ≤140 to ≥220 Gy, which demonstrated a progressive decrease in the positive biopsy rate to 1.5% at the highest dose (p = 0.036). PSA was <0.2 ng/mL in 98.2% of these men. If brachytherapy was used for PGA and a dose of ≥ 220 Gy was delivered to the ablation zone, the nPSA could be calculated from the remaining untreated volume as: the [(pretreatment PV)–treated volume] ×0.12 ng/mL2. Conclusion A method for determining the nPSA following PGA using brachytherapy was developed. The formula relies on complete ablation of the treated volume, which resulted in no PSA contribution from that component. Other forms of ablative energy should yield similar results. Further clinical validation of this concept is warranted.
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spelling doaj-art-c1bf8377836e4d2eb147cd4e4c36b5312025-08-20T02:45:52ZengWileyBJUI Compass2688-45262025-02-0162n/an/a10.1002/bco2.496Method to determine the nadir PSA following partial gland ablationNelson N. Stone0Vassilios Skouteris1Rendi Shu2Richard G. Stock3Ben GL Vanneste4Department of Urology The Icahn School of Medicine at Mount Sinai New York New York USABrachytherapy Center Hygeia Hospital Athens GreeceDepartment of Radiation Oncology The Icahn School of Medicine at Mount Sinai New York New York USADepartment of Radiation Oncology The Icahn School of Medicine at Mount Sinai New York New York USADepartment of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction Maastricht University Medical Centre+ Maastricht The NetherlandsAbstract Objectives The objective of this study is to propose a novel method of determining the nadir PSA (nPSA) for men with prostate cancer treated by partial gland ablation (PGA). Materials and Methods Two cohorts of men were analyzed to develop a formula for the nPSA in men undergoing PGA. First, 123 men with a suspicion of prostate cancer underwent transperineal mapping biopsy (TPMB) and found to have benign pathology. Their prostate‐specific antigen (PSA) was compared to the prostate volume using curve estimation regression analysis. Second, the contribution of PSA from an ablated region was determined by using a surrogate of 545 men who had whole‐gland brachytherapy followed by prostate biopsy. Biopsy results were compared to radiation dose (calculated as the biological equivalent dose) levels in men who were free from biochemical failure. The nPSA was then calculated by using the PSA density (PSAD) for the untreated volume plus the PSA from the post‐brachytherapy patients. Results The PSAD with the highest R2 (0.80, p < 0.001) for the 123 men who had TPMB and a negative biopsy was 0.12 ng/mL2. In the brachytherapy patients, five 20 Gy dose groups were analyzed from ≤140 to ≥220 Gy, which demonstrated a progressive decrease in the positive biopsy rate to 1.5% at the highest dose (p = 0.036). PSA was <0.2 ng/mL in 98.2% of these men. If brachytherapy was used for PGA and a dose of ≥ 220 Gy was delivered to the ablation zone, the nPSA could be calculated from the remaining untreated volume as: the [(pretreatment PV)–treated volume] ×0.12 ng/mL2. Conclusion A method for determining the nPSA following PGA using brachytherapy was developed. The formula relies on complete ablation of the treated volume, which resulted in no PSA contribution from that component. Other forms of ablative energy should yield similar results. Further clinical validation of this concept is warranted.https://doi.org/10.1002/bco2.496biochemical failurebiopsyfocal therapynadir PSAprostate cancerradiation dose
spellingShingle Nelson N. Stone
Vassilios Skouteris
Rendi Shu
Richard G. Stock
Ben GL Vanneste
Method to determine the nadir PSA following partial gland ablation
BJUI Compass
biochemical failure
biopsy
focal therapy
nadir PSA
prostate cancer
radiation dose
title Method to determine the nadir PSA following partial gland ablation
title_full Method to determine the nadir PSA following partial gland ablation
title_fullStr Method to determine the nadir PSA following partial gland ablation
title_full_unstemmed Method to determine the nadir PSA following partial gland ablation
title_short Method to determine the nadir PSA following partial gland ablation
title_sort method to determine the nadir psa following partial gland ablation
topic biochemical failure
biopsy
focal therapy
nadir PSA
prostate cancer
radiation dose
url https://doi.org/10.1002/bco2.496
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