Intermittent maximal androgen blockade in patients with metastatic prostate cancer: an EORTC feasibility study.
OBJECTIVE
In preparation of an intercontinental Phase III trial comparing continuous maximal androgen blockade (MAB) to intermittent androgen suppression (IAS) in untreated metastatic prostate cancer, a feasibility study on IAS was accomplished.


METHODS
107 patients (median follow-up 92 weeks) were treated with MAB until a PSA nadir was reached. Nadir was defined as PSA below 20 ng/ml corresponding to PSA reduction by at least 80% of baseline value. Criteria for restarting treatment was PSA >20 ng/ml and PSA > nadir + 50%. Trials aim was to assess the likelihood that 80% of patients would reach a first nadir and that 80% of these would also reach a second nadir.


RESULTS
51.4% of patients had some degree of pain at entry, 27.1% had >15 hot spots, 23.7% demonstrated obstruction. Only 17.8% had normal potency, 56.1% were totally impotent. One to seven cycles of treatment were given. 76.6% of patients reached a 1st nadir after a median of 19 weeks of treatment, 84.1% of these started the 2nd cycle and 71% of them reached a 2nd nadir after a median of 13.6 weeks. Median time off-treatment was 14.3 and 16.0 weeks corresponding to 38.4% and 48.5% of the duration of each cycle. A similar proportion of patients was reported to be potent during follow-up compared to baseline. 32.7% of patients died during follow-up, 82.9% of prostate cancer.


CONCLUSIONS
Around 75% of the patients achieved a nadir at each cycle. The concept of IAS seems to be feasible and warrants further investigation.
Albrecht
Walter
W
Department of Urology, Rudolfstiftung, Juchgasse 25, A 1030, Vienna, Austria. walter.albrecht@kar.magwien.gv.at
Collette
Laurence
L
Fava
Cesare
C
Kariakine
Oleg B
OB
Whelan
Peter
P
Studer
Urs E
UE
De Reijke
Theo M
TM
Kil
Paul J
PJ
Rea
Lesley A
LA
D000368:Aged; D000726:Androgen Antagonists / Q000008:administration & dosage; D000813:Anilides / Q000008:administration & dosage; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D018450:Disease Progression; D005240:Feasibility Studies; D017273:Goserelin / Q000008:administration & dosage; D006801:Humans; D008297:Male; D009570:Nitriles; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D014105:Tosyl Compounds; D016896:Treatment Outcome
D000726:Androgen Antagonists; D000813:Anilides; D018931:Antineoplastic Agents, Hormonal; D009570:Nitriles; D014105:Tosyl Compounds; D017273:Goserelin; C053541:bicalutamide; D017430:Prostate-Specific Antigen