Prostate-specific antigen level at initiation of hormonal therapy after prostate-specific antigen failure following prostatectomy or radiotherapy and therapeutic response.
OBJECTIVE
To determine the pretreatment factors associated with an undetectable prostate-specific antigen (PSA) nadir after 8 months of androgen suppression therapy (AST).


METHODS
The study cohort comprised 137 men with an increasing PSA level after surgery or radiotherapy performed for localized prostate cancer who had undergone AST. Cox regression multivariate analyses were used to identify the factors associated with a PSA nadir of 0.2 ng/mL or less 8 months after AST initiation.


RESULTS
The PSA level at the initiation of AST was associated with a PSA nadir of 0.2 ng/mL or less after 8 months of AST, as both a continuous variable (adjusted odds ratio [OR] 0.44, P = 0.0001) and a categorical variable, with PSA greater than 10 ng/mL (OR 0.16, P = 0.007). The percentage of patients with a PSA nadir of 0.2 ng/mL or less was 86%, 72%, 75%, 67%, and 25% for men with a PSA level at the initiation of AST of 4 ng/mL or less, greater than 4 to 10 ng/mL, greater than 10 to 20 ng/mL, greater than 20 to 50 ng/mL, and greater than 50 ng/mL, respectively.


CONCLUSIONS
An elevated PSA level before the initiation of AST was significantly associated with a decreased chance of a PSA nadir of 0.2 ng/mL or less after 8 months of AST. Given the association between the PSA nadir after AST and prostate-cancer specific mortality, men with increasing PSA levels could be considered for Phase II and III clinical trials evaluating the effect of adding novel systemic therapies to AST on the interval to prostate-cancer specific mortality.
Alexander
Brian M
BM
Harvard Radiation Oncology Program, Boston, Massachusetts 02115, USA. bmalexander@partners.org
Chen
Ming-Hui
MH
Carroll
Peter
P
D'Amico
Anthony V
AV
D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood* / Q000532:radiotherapy / Q000601:surgery / Q000628:therapy*; D017211:Treatment Failure