Prostate-specific antigen kinetics following external-beam radiotherapy and temporary (Ir-192) or permanent (I-125) brachytherapy for prostate cancer

• Published in: Radiotherapy and oncology Vol. 96; no. 1; pp. 25 - 29
• Main Authors: Pinkawa, Michael, Piroth, Marc D., Holy, Richard, Fischedick, Karin, Schaar, Sandra, Borchers, Holger, Heidenreich, Axel, Eble, Michael J.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.07.2010
• Subjects: Adenocarcinoma - blood; Adenocarcinoma - mortality; Adenocarcinoma - pathology; Adenocarcinoma - radiotherapy; Aged; Aged, 80 and over; Brachytherapy; Brachytherapy - methods; Chi-Square Distribution; Cohort Studies; Confidence Intervals; Dose-Response Relationship, Radiation; Follow-Up Studies; Hematology, Oncology, and Palliative Medicine; Hormone therapy; Humans; I-125; Ir-192; Kaplan-Meier Estimate; Male; Middle Aged; Neoplasm Staging; Proportional Hazards Models; Prostate cancer; Prostate-specific antigen; Prostate-Specific Antigen - pharmacokinetics; Prostate-Specific Antigen - radiation effects; Prostatic Neoplasms - blood; Prostatic Neoplasms - mortality; Prostatic Neoplasms - pathology; Prostatic Neoplasms - radiotherapy; Radiotherapy; Radiotherapy Dosage; Radiotherapy, High-Energy - methods; Risk Assessment; Survival Rate; Time Factors; Treatment Outcome; Hormone therapy; Prostate-specific antigen; I-125; Brachytherapy; Ir-192; Radiotherapy; Prostate cancer
• ISSN: 0167-8140; 1879-0887; 1879-0887
• DOI: 10.1016/j.radonc.2010.02.010

The aim of the study was the evaluation of PSA kinetics after different radiotherapy methods. Two-hundred and ninety five patients received external-beam radiotherapy (EBRT; 70.2 Gy; n = 135), Ir-192 brachytherapy as a boost to EBRT (HDR-BT; 18 Gy + 50.4 Gy; n = 66) or I-125 brachytherapy (LDR-BT; 145 Gy; n = 94) as monotherapy. “PSA bounce” was defined as a PSA rise of ⩾0.2 ng/ml followed by spontaneous return to prebounce level or lower, biochemical failure as “nadir + 2 ng/ml”. Patients without biochemical failure reached a lower nadir after brachytherapy (median ⩽0.05 ng/ml after LDR- and HDR-BT without NHT) in comparison to EBRT (0.55 ng/ml without NHT; p < 0.01). Not a single patient without NHT and a nadir <0.1 ng/ml failed biochemically (0% vs. 45% with a nadir ⩾0.1 ng/ml; p < 0.01). PSA bounces were found predominantly in the LDR-BT group (42% vs. 23%/20% after HDR-BT/EBRT; p < 0.01). In a multivariate Cox regression analysis, LDR-BT and HDR-BT were associated with a significantly lower biochemical failure rate in comparison to EBRT. PSA kinetics differ significantly following different radiotherapy methods. A lower nadir and a higher biochemical control rate suggest a higher radiobiological efficiency of brachytherapy in comparison to EBRT (with a dose of 70.2 Gy).