Biochemical and clinical significance of the posttreatment prostate-specific antigen bounce for prostate cancer patients treated with external beam radiation therapy alone: a multiinstitutional pooled analysis.
BACKGROUND
The posttreatment prostate-specific antigen (PSA) bounce phenomenon has been recognized in at least 20% of all patients treated with radiation. The purpose of the current report was to determine if there was a difference in biochemical and clinical control between the bounce and nonbounce (NB) patients using pooled data on 4839 patients with T1-2 prostate cancer treated with external beam radiation therapy (RT) alone at 9 institutions between 1986 and 1995.


METHODS
The median follow-up was 6.3 years. A posttreatment PSA bounce was defined by a minimal rise of 0.4 ng/mL over a 6-month follow-up period, followed by a drop in PSA level of any magnitude. Endpoints included no biochemical evidence of disease (bNED) failure (BF) (ASTRO definition), distant failure (DF), cause-specific failure (CSF), and overall survival (OS). Patients were stratified by pretreatment PSA, Gleason score, T stage, age, dose, and risk group.


RESULTS
In all, 978 (20%) patients experienced at least 1 posttreatment PSA bounce. Within 3 subgroups (risk group, pretreatment PSA, and age), statistically significant differences of remaining bounce-free were observed on univariate analysis. Patients < 70 years had a 72% chance of remaining bounce-free at 5 years compared with 75% for older patients (P = .04). The NB patients had 72% bNED control at 10 years compared with 58% for the bounce patients. The effect of a bounce remained statistically significant on multivariate analysis (P < .0001). No statistically significant difference in DF, CSF, or OS was observed.


CONCLUSIONS
Patients treated with external beam radiation therapy alone who experience a posttreatment PSA bounce have increased risk of BF. However, this did not translate into a difference in clinical failure with the available follow-up in the current study.
Horwitz
Eric M
EM
Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA. eric.horwitz@fccc.edu
Levy
Lawrence B
LB
Thames
Howard D
HD
Kupelian
Patrick A
PA
Martinez
Alvaro A
AA
Michalski
Jeffrey M
JM
Pisansky
Thomas M
TM
Sandler
Howard M
HM
Shipley
William U
WU
Zelefsky
Michael J
MJ
Zietman
Anthony L
AL
Kuban
Deborah A
DA
D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000532:radiotherapy*; D012306:Risk; D017211:Treatment Failure
D017430:Prostate-Specific Antigen