Post-therapy serum prostate-specific antigen level and survival in patients with androgen-independent prostate cancer.
BACKGROUND
With an hypothesis that post-chemotherapy changes in serum prostate-specific antigen (PSA) levels might serve as a surrogate marker for assessing prostate cancer outcome (i.e., survival), we studied the relationship between pretherapy and post-therapy prognostic factors and survival in patients with androgen-independent prostate cancer.


METHODS
A prognostic model for survival based on pretherapy and post-therapy parameters was developed from the clinical data on 254 patients with androgen-independent prostate cancer treated with 11 different protocol therapies at Memorial Sloan-Kettering Cancer Center. The model was validated by use of an independent dataset of 541 patients enrolled in two randomized phase III trials.


RESULTS
In multivariate analysis, a post-therapy decline in PSA levels of 50% achieved in 12 weeks was a statistically significant factor associated with survival (two-sided P = .0012). A similar outcome was obtained with the use of an 8-week time frame. Elevated pretherapy level of serum lactate dehydrogenase (two-sided P = .0001), lower pretherapy level of hemoglobin (P = .0001), and younger age (two-sided P = .0430) had a statistically significant negative impact on outcome. Median survival times were 23, 17, and 9 months for low-, intermediate-, and high-risk groups of patients defined by the prognostic model, respectively.


CONCLUSIONS
This study confirms the prognostic value of a post-therapy decline in PSA of 50% or greater from baseline in relation to survival in patients with androgen-independent prostate cancer treated with a variety of therapies. Two consecutive determinations at 4-week intervals can be used as an end point for efficacy in phase II trials of therapies in this disease.
Scher
H I
HI
Department of Medicine, Memorial Sloan-Kettering Cancer Center, and Cornell University Medical College, New York, NY 10021, USA.
Kelly
W M
WM
Zhang
Z F
ZF
Ouyang
P
P
Sun
M
M
Schwartz
M
M
Ding
C
C
Wang
W
W
Horak
I D
ID
Kremer
A B
AB
D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000276:immunology* / Q000628:therapy; D015203:Reproducibility of Results; D012307:Risk Factors; D016019:Survival Analysis
D017430:Prostate-Specific Antigen