Clinical significance of a prostate-specific antigen flare phenomenon in patients with hormone-refractory prostate cancer receiving docetaxel.
Docetaxel has shown promise for the treatment of hormone-refractory prostate cancer and has become the standard of care. The flare phenomenon is a known entity in androgen-deprivation therapy of advanced prostate cancer and it has also been described in palliative chemotherapy of hormone-refractory prostate cancer. The aim of this study was to evaluate the clinical impact of a prostate-specific antigen flare phenomenon in docetaxel-treated hormone-refractory prostate cancer patients. From December 2002 to August 2005, we treated 44 patients with hormone-refractory prostate cancer applying docetaxel-based regimens. Prostate-specific antigen levels were determined before therapy and weekly thereafter. Patients were divided into three groups: response (group 1), progression (group 2) and flare (group 3). Flare was defined as initially rising prostate-specific antigen under therapy, dropping thereafter to values below baseline. The groups were compared for overall survival by Kaplan-Meier analysis. We observed a prostate-specific antigen flare phenomenon in eight (18%) of 44 evaluable patients; 24 (54.5%) patients were primary responders and 12 (27.3%) experienced progressive disease. In group 3, prostate-specific antigen levels rose to 107-180% from baseline and then dropped to 21-68%. Kaplan-Meier analysis showed significantly better overall median survival for groups 1 (18 months, P=0.0005) and 3 (19 months, P=0.006) than for group 2 (7 months). Survival in groups 1 and 3 was comparable. Grade 3 and 4 toxicity was below 5% and equally distributed between the 3 groups. In our limited patient cohort, prostate-specific antigen flare phenomenon does not seem to be a clinically relevant issue in terms of overall survival. Thus, an initial rise of prostate-specific antigen under docetaxel therapy in hormone-refractory prostate cancer does not indicate therapeutic failure and should not lead to early withdrawal from therapy in the absence of clinical signs of progression.
Olbert
Peter Jochen
PJ
Department of Urology and Pediatric Urology, Philipps University Medical School, Baldingerstrasse, 35043 Marburg, Germany. peter.olbert@med.uni-marburg.de
Hegele
Axel
A
Kraeuter
Petra
P
Heidenreich
Axel
A
Hofmann
Rainer
R
Schrader
Andres Jan
AJ
D000728:Androgens / Q000502:physiology; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D000077143:Docetaxel; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000401:mortality; D015996:Survival Rate; D043823:Taxoids / Q000627:therapeutic use*
D000728:Androgens; D000972:Antineoplastic Agents, Phytogenic; D043823:Taxoids; D000077143:Docetaxel; D017430:Prostate-Specific Antigen