Absolute prostate-specific antigen value after androgen deprivation is a strong independent predictor of survival in new metastatic prostate cancer: data from Southwest Oncology Group Trial 9346 (INT-0162).
OBJECTIVE
To establish whether absolute prostate-specific antigen (PSA) value after androgen deprivation (AD) is prognostic in metastatic (D2) prostate cancer (PCa).


METHODS
D2 PCa patients with baseline PSA of at least 5 ng/mL received 7 months induction AD. Patients achieving PSA of 4.0 ng/mL or less on months 6 and 7 are randomly assigned to continuous versus intermittent AD on month 8. Eligibility for this analysis required a prestudy PSA with at least two subsequent PSAs and that patients be registered at least 1 year before analysis date. Survival was defined as time to death after 7 months of AD. Associations were evaluated by proportional hazards regression models.


RESULTS
One thousand one hundred thirty four of 1,345 eligible patients achieved a PSA of 4 ng/mL or less. At end of induction, 965 patients maintained PSA of 4 or less and 604 had a PSA of 0.2 ng/mL or less. After controlling for prognostic factors, patients with a PSA of 4 or less to more than 0.2 ng/mL had less than one third the risk of death (ROD) as those with a PSA of more than 4 ng/mL (P < .001). Patients with PSA of 0.2 ng/mL or less had less than one fifth the ROD as patients with a PSA of more than 4 ng/mL (P < .001) and had significantly better survival than those with PSA of more than 0.2 to 4 ng/mL or less (P < .001). Median survival was 13 months for patients with a PSA of more than 4 ng/mL, 44 months for patients with PSA of more than 0.2 to 4 ng/mL or less, and 75 months for patients with PSA of 0.2 ng/mL or less.


CONCLUSIONS
A PSA of 4 ng/mL or less after 7 months of AD is a strong predictor of survival. This data should be used to tailor future trial design for D2 prostate cancer.
Hussain
Maha
M
University of Michigan, Ann Arbor, MI, USA.
Tangen
Catherine M
CM
Higano
Celestia
C
Schelhammer
Paul F
PF
Faulkner
James
J
Crawford
E David
ED
Wilding
George
G
Akdas
Atif
A
Small
Eric J
EJ
Donnelly
Bryan
B
MacVicar
Gary
G
Raghavan
Derek
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000276:immunology* / Q000401:mortality / Q000473:pathology; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors
D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen