• Daniel J Krauss, Chen Hu, Jean-Paul Bahary, Luis Souhami, Elizabeth M Gore, Susan Maria Jacinta Chafe, Mark H Leibenhaut, Samir Narayan, Javier Torres-Roca, Jeff Michalski, Kenneth L Zeitzer, Viroon Donavanik, Howard Sandler, David G McGowan, Christopher U Jones, and William U Shipley.
• Department of Radiation Oncology, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan. Electronic address: dkrauss@beaumont.edu.
• Int. J. Radiat. Oncol. Biol. Phys. 2015 Jul 15; 92 (4): 863-73.

PurposeThe purpose of this study was to assess the association between positive post-radiation therapy (RT) biopsy results and subsequent clinical outcomes in males with localized prostate cancer.Methods And MaterialsRadiation Therapy Oncology Group study 94-08 analyzed 1979 males with prostate cancer, stage T1b-T2b and prostate-specific antigen concentrations of ≤ 20 ng/dL, to investigate whether 4 months of total androgen suppression (TAS) added to RT improved survival compared to RT alone. Patients randomized to receive TAS received flutamide with luteinizing hormone releasing hormone (LHRH) agonist. According to protocol, patients without evidence of clinical recurrence or initiation of additional endocrine therapy underwent repeat prostate biopsy 2 years after RT completion. Statistical analysis was performed to evaluate the impact of positive post-RT biopsy results on clinical outcomes.ResultsA total of 831 patients underwent post-RT biopsy, 398 were treated with RT alone and 433 with RT plus TAS. Patients with positive post-RT biopsy results had higher rates of biochemical failure (hazard ratio [HR] = 1.7; 95% confidence interval [CI] = 1.3-2.1) and distant metastasis (HR = 2.4; 95% CI = 1.3-4.4) and inferior disease-specific survival (HR = 3.8; 95% CI = 1.9-7.5). Positive biopsy results remained predictive of such outcomes after correction for potential confounders such as Gleason score, tumor stage, and TAS administration. Prior TAS therapy did not prevent elevated risk of adverse outcome in the setting of post-RT positive biopsy results. Patients with Gleason score ≥ 7 with a positive biopsy result additionally had inferior overall survival compared to those with a negative biopsy result (HR = 1.56; 95% CI = 1.04-2.35).ConclusionsPositive post-RT biopsy is associated with increased rates of distant metastases and inferior disease-specific survival in patients treated with definitive RT and was associated with inferior overall survival in patients with high-grade tumors.Copyright © 2015 Elsevier Inc. All rights reserved.

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