The Importance of Prostate-specific Antigen (PSA) Nadir and Early Identification of PSA Relapse after 10 Years of Prostate Iodine 125 Seed Brachytherapy in Edinburgh

• Published in: Clinical oncology (Royal College of Radiologists (Great Britain)) Vol. 27; no. 9; pp. 519 - 526
• Main Authors: McLaren, D B, Kerr, G, Law, A B, Brush, J P, Keanie, J, Malik, J, Keough, W, Ronaldson, T, Lee, J, Kehoe, T
• Format: Journal Article
• Language: English
• Published: England 01-09-2015
• Subjects: Adult; Aged; Brachytherapy - methods; Follow-Up Studies; Humans; Iodine Radioisotopes - administration & dosage; Male; Middle Aged; Neoplasm Recurrence, Local - blood; Predictive Value of Tests; Prognosis; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - radiotherapy; PSA nadir; prostate cancer; Iodine seed brachytherapy; relapse; salvage treatment
• ISSN: 1433-2981
• DOI: 10.1016/j.clon.2015.05.003

To analyse our 5 and 10 year prostate brachytherapy outcome data and to assess the impact of PSA nadir on relapse free survival and whether an alternative definition of PSA relapse could detect men destined to fail by the Phoenix definition at an earlier time point.
474 men were treated over a 10 year period between 20012 and 2011 and divided into 2 five year cohorts for the purpose of the analysis.
The risk of relapse is strongly predicted by post treat prostate-specific antigen (PSA) nadir. After 3 years post-treatment, PSA nadir plus 0.4 ng/ml identified men at risk of relapse 17 months earlier than the Phoenix definition.
The Phoenix definition of nadir plus 2.0 ng/ml does not allow the early identification of men destined to relapse. The initiation of salavage therapy at the earliest opportunity could potentially affect subsequent survival and an outline randomised controlled trial proposal is presented.