A comparison of the prognostic value of early PSA test-based variables following external beam radiotherapy, with or without preceding androgen deprivation: analysis of data from the TROG 96.01 randomized trial.
OBJECTIVE
We sought to compare the prognostic value of early prostate-specific antigen (PSA) test-based variables for the 802 eligible patients treated in the Trans-Tasman Radiation Oncology Group 96.01 randomized trial.


METHODS
Patients in this trial had T2b, T2c, T3, and T4 N0 prostate cancer and were randomized to 0, 3, or 6 months of neoadjuvant androgen deprivation therapy (NADT) prior to and during radiation treatment at 66 Gy to the prostate and seminal vesicles. The early PSA test-based variables evaluated were the pretreatment initial PSA (iPSA) value, PSA values at 2 and 4 months into NADT, the PSA nadir (nPSA) value after radiation in all patients, and PSA response signatures in men receiving radiation. Comparisons of endpoints were made using Cox models of local progression-free survival, distant failure-free survival, biochemical failure-free survival, and prostate cancer-specific survival.


RESULTS
The nPSA value was a powerful predictor of all endpoints regardless of whether NADT was given before radiation. PSA response signatures also predicted all endpoints in men treated by radiation alone. iPSA and PSA results at 2 and 4 months into NADT predicted biochemical failure-free survival but not any of the clinical endpoints. nPSA values correlated with those of iPSA, Gleason grade, and T stage and were significantly higher in men receiving radiation alone than in those receiving NADT.


CONCLUSIONS
The postradiation nPSA value is the strongest prognostic indicator of all early PSA-based variables. However, its use as a surrogate endpoint needs to take into account its dependence on pretreatment variables and treatment method.
Lamb
David S
DS
University of Otago, Wellington, New Zealand. david.lamb@otago.ac.nz
Denham
James W
JW
Joseph
David
D
Matthews
John
J
Atkinson
Chris
C
Spry
Nigel A
NA
Duchesne
Gillian
G
Ebert
Martin
M
Steigler
Allison
A
Delahunt
Brett
B
D'Este
Catherine
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D018709:Statistics, Nonparametric
D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen