Prostate cancer patient subsets showing improved bNED control with adjuvant androgen deprivation.
OBJECTIVE
Cooperative groups have investigated the outcome of androgen deprivation therapy combined with radiation therapy in prostate cancer patients with variable pretreatment prognostic indicators. This report describes an objective means of selecting patients for adjuvant hormonal therapy by a retrospective matched case/control comparison of outcome between patients with specific pretreatment characteristics who receive adjuvant hormones (RT+H) vs. patients with identical pretreatment characteristics treated with radiation therapy alone (RT). In addition, this report shows the 5-year bNED control for patients selected by this method for RT+H vs. RT alone.


METHODS
From 10/88 to 12/93, 517 T1-T3 NXM0 patients with known pretreatment PSA level were treated at Fox Chase Cancer Center. Four hundred fifty-nine of those patients were treated with RT alone while 58 were treated with RT+H. The patients were categorized according to putative prognostic factors indicative of bNED control, which include the palpation stage, Gleason score, and pretreatment PSA. We compared actuarial bNED control rates according to treatment group within each of the prognostic groups. In addition, we devised a retrospective matched case/control selection of RT patients for comparison with the RT+H group. Five-year bNED control was compared for the two treatment groups, excluding the best prognosis group, using 56 RT+H patients and 56 matched (by stage, grade, and pretreatment PSA level) controls randomly selected from the RT alone group. bNED control for the entire group of 517 patients was then analyzed multivariately using step-wise Cox regression to determine independent predictors of outcome. Covariates considered for entry into the model included stage (T1/T2AB vs. T2C/T3), grade (2-6 vs. 7-10), pretreatment PSA (0-15 vs. > 15), treatment (RT vs. RT+H), and center of prostate dose. bNED failure is defined as PSA > or = 1.5 ngm/ml and rising on two consecutive determinations. The median follow-up for the 112 matched case/control patients was 41 months. The median follow-up was 46 months for the RT (range 11-102 months) and 37 months for the RT+H group (range 6-82 months).


RESULTS
Univariate analysis according to treatment for the prognostic factors of palpation stage, Gleason score, and pretreatment PSA demonstrates a significant improvement in 3-year bNED control with the addition of hormones for patients with T2C/T3, Gleason score 7-10, or pretreatment PSA > 15 ngm/ml. A comparison of bNED control according to treatment demonstrates improvement in 5-year bNED control of 55% for patients treated with RT+H vs. 31% for those patients treated with RT alone (p = 0.0088), although there is not a survival advantage. Multivariate analysis demonstrates that hormonal treatment is a highly significant independent predictor of bNED control (p = 0.0006) along with pretreatment PSA (p = 0.0001), palpation stage (p = 0.0001), grade (p = 0.0030), and dose (p = 0.0001).


CONCLUSIONS
(1) Patients with specific adverse pretreatment prognostic factors (i.e., T2C/T3, Gleason score 7-10, pretreatment PSA > 15) benefit from adjuvant hormonal therapy. (2) Upon multivariate analysis, hormonal therapy is determined to be a highly significant predictor of bNED control, after adjusting for all other covariates. (3) The 5-year bNED control rates of 55% for RT+H vs. 31% for RT alone represents the magnitude of benefit from adjuvant hormone therapy. (4) The bNED control curves are separated by about 20 months, representing a delay in disease progression with adjuvant hormonal therapy, as there is no overall survival difference.
Anderson
P R
PR
Department of Radiation Oncology Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
Hanlon
A L
AL
Movsas
B
B
Hanks
G E
GE
D000704:Analysis of Variance; D000726:Androgen Antagonists / Q000008:administration & dosage; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D016022:Case-Control Studies; D003131:Combined Modality Therapy; D005485:Flutamide / Q000008:administration & dosage; D017273:Goserelin / Q000627:therapeutic use*; D006801:Humans; D016729:Leuprolide / Q000627:therapeutic use*; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000532:radiotherapy*; D012189:Retrospective Studies
D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D017273:Goserelin; D005485:Flutamide; D017430:Prostate-Specific Antigen; D016729:Leuprolide