Is biochemical response more important than duration of neoadjuvant hormone therapy before radiotherapy for clinically localized prostate cancer? An analysis of the 3- versus 8-month randomized trial.
OBJECTIVE
To ascertain whether biochemical response to neoadjuvant androgen-deprivation therapy (ADT) before radiotherapy (RT), rather than duration, is the critical determinant of benefit in the multimodal treatment of localized prostate cancer, by comparing outcomes of subjects from the Canadian multicenter 3- vs 8-month trial with a pre-RT, post-hormone PSA (PRPH-PSA) < or =0.1 ng/ml vs those >0.1 ng/ml.


METHODS
From 1995 to 2001, 378 men with localized prostate cancer were randomized to 3 or 8 months of neoadjuvant ADT before RT. On univariate analysis, survival indices were compared between those with a PRPH-PSA < or =0.1 ng/ml vs >0.1 ng/ml, for all patients and subgroups, including treatment arm, risk group, and gleason Score. Multivariate analysis identified independent predictors of outcome.


RESULTS
Biochemical disease-free survival (bDFS) was significantly higher for those with a PRPH-PSA < or =0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (55.3% vs 49.4%, p = 0.014). No difference in survival indices was observed between treatment arms. There was no difference in bDFS between patients in the 3- and 8-month arms with a PRPH-PSA < or =0.1 ng/ml nor those with PRPH-PSA >0.1 ng/ml. bDFS was significantly higher for high-risk patients with PRPH-PSA < or =0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (57.0% vs 29.4%, p = 0.017). Multivariate analysis identified PRPH-PSA (p = 0.041), Gleason score (p = 0.001), initial PSA (p = 0.025), and T-stage (p = 0.003), not ADT duration, as independent predictors of outcome.


CONCLUSIONS
Biochemical response to neoadjuvant ADT before RT, not duration, appears to be the critical determinant of benefit in the setting of combined therapy. Individually tailored ADT duration based on PRPH-PSA would maximize therapeutic gain, while minimizing the duration of ADT and its related toxicities.
Alexander
Abraham
A
Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, University of British Columbia, Victoria, BC, Canada. aalexander3@bccancer.bc.ca
Crook
Juanita
J
Jones
Stuart
S
Malone
Shawn
S
Bowen
Julie
J
Truong
Pauline
P
Pai
Howard
H
Ludgate
Charles
C
D000230:Adenocarcinoma / Q000097:blood* / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D000368:Aged; D000704:Analysis of Variance; D000726:Androgen Antagonists / Q000008:administration & dosage; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D018572:Disease-Free Survival; D005485:Flutamide / Q000008:administration & dosage; D017273:Goserelin / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D013997:Time Factors
D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D017273:Goserelin; D005485:Flutamide; D017430:Prostate-Specific Antigen