PURPOSE: To characterize the magnitude and kinetics of prostate-specific antigen (PSA) bounces after high-dose-rate (HDR) monotherapy and determine relationships between certain clinical factors and PSA bounce.
METHODS AND MATERIALS: Longitudinal PSA data and various clinical parameters were examined in 157 consecutive patients treated with HDR monotherapy between 1996 and 2005. We used the following definition for PSA bounce: rise in PSA ≥threshold, after which it returns to the prior level or lower. Prostate-specific antigen failure was defined per the Phoenix definition (nadir +2 ng/mL).
RESULTS: A PSA bounce was noted in 67 patients (43%). The number of bounces per patient was 1 in 45 cases (67%), 2 in 19 (28%), 3 in 2 (3%), 4 in 0, and 5 in 1 (1%). The median time to maximum PSA bounce was 1.3 years, its median magnitude was 0.7, and its median duration was 0.75 years. Three patients (2%) were noted to have PSA failure. None of the 3 patients who experienced biochemical failure exhibited PSA bounce. In the fully adjusted model for predicting each bounce, patients aged < 55 years had a statistically significant higher likelihood of experiencing a bounce (odds ratio 2.22, 95% confidence interval 1.38-3.57, P=.001). There was also a statistically significant higher probability of experiencing a bounce for every unit decrease in Gleason score (odds ratio 1.52, 95% confidence interval 1.01-2.04, P=.045).
CONCLUSIONS: A PSA bounce occurs in a significant percentage of patients treated with HDR monotherapy, with magnitudes varying from < 1 in 28% of cases to ≥1 in 15%. The median duration of bounce is < 1 year. More bounces were identified in patients with lower Gleason score and age < 55 years. Further investigation using a model to correlate magnitude and frequency of bounces with clinical variables are under way.
Written by:
Mehta NH, Kamrava M, Wang PC, Steinberg M, Demanes J. Are you the author?
University of California, Los Angeles, Los Angeles, California.
Reference: Int J Radiat Oncol Biol Phys. 2013 Apr 11. pii: S0360-3016(13)00256-3.
doi: 10.1016/j.ijrobp.2013.02.032
PubMed Abstract
PMID: 23582852
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