INTRODUCTION: Following radical prostatectomy for adenocarcinoma of the prostate, a long-term undetectable PSA level is associated with cure. Cure may also be defined by persistently low PSA levels after radiation, with the assumption that residual benign prostate tissue may produce low levels of PSA. There is no established PSA nadir following radiation therapy that has been universally associated with cure. The purpose of this study was to determine the frequency of undetectable PSA following prostate brachytherapy.
METHODS: A total of 163 patients were treated with radioactive iodine-125 seed implantation as definitive treatment, between 1996 and 2003. No patients received external radiation or hormone therapy. Posttreatment PSA levels were reviewed to ascertain the number of patients with PSA levels that were undetectable, ≤ 0.2, ≤ 0.3, and ≤ 0.5 ng/mL. PSA failure was based on the ASTRO consensus definition.
RESULTS: At a median follow-up of 85.2 months, 120 patients (73.6%) achieved and maintained an undetectable PSA level. Twenty-three patients (14%) experienced biochemical failure by the ASTRO definition; 80%, 83%, and 85% achieved and maintained PSA nadirs of ≤ 0.2, ≤ 0.3, and ≤ 0.5 ng/mL, respectively. Comparing outcomes of patients treated with radical prostatectomy and radiation therapy for prostate cancer is difficult, due to different PSA patterns following treatment and varying definitions of success. The present study showed that an undetectable PSA level after brachytherapy is consistently associated with disease-free state, which reflects the durability of that biochemical status. It matches the most stringent definition of disease freedom following prostatectomy.
CONCLUSIONS: Comparing outcomes of patients treated with radical prostatectomy and radiation therapy for prostate cancer is difficult, due to different PSA patterns following treatment and varying definitions of success. The present study showed that an undetectable PSA level after brachytherapy is consistently associated with disease-free state, which reflects the durability of that biochemical status. It matches the most stringent definition of disease freedom following prostatectomy.
William L. Barrett
KEYWORDS: Prostate cancer; Brachytherapy; Prostatectomy
CORRESPONDENCE: William L. Barrett, MD, Department of Radiation Oncology, University of Cincinnati College of Medicine, 234 Goodman Street ML 0757, Cincinnati, Ohio 45267-0757 USA ( ).
CITATION: Urotoday Int J. 2010 Apr;3(2)
doi: 10.3834/uij.1944-5784.2010.04.16