Rapid rise of serum prostate specific antigen levels after discontinuation of the herbal therapy PC-SPES in patients with advanced prostate carcinoma: report of four cases.
BACKGROUND
PC-SPES is an herbal supplement whose mechanisms of action are poorly understood, but may be estrogenic. The objective of the current report is to describe the effects of discontinuing PC-SPES treatment in four patients with androgen-independent prostate carcinoma.


METHODS
Patient charts were retrospectively reviewed. A MEDLINE search was performed to investigate whether these effects of PC-SPES had been previously reported.


RESULTS
Four men whose metastatic prostate carcinoma progressed despite androgen ablation and subsequent PC-SPES treatment are described. All four patients developed a rapid increase in serum prostate specific antigen (PSA) within one month of stopping PC-SPES, ranging from 345% to 880%. Two patients increased their PSA levels to 1300% and 1400% after 7 weeks. Compared to the rate of rise of PSA levels prior to and during PC-SPES therapy, the rise after stopping this treatment was much higher than expected. Clinical symptoms remained relatively stable despite the serologic changes.


CONCLUSIONS
Discontinuing PC-SPES therapy can be associated with a rapid rise in PSA. To the authors' knowledge, this effect has not been reported previously. This effect should be considered in the design of clinical trials as well as in the standard management of androgen-independent prostate carcinoma patients.
Oh
William K
WK
The Lank Center for Genitourinary Oncology, Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. william_oh@dfci.harvard.edu
George
Daniel J
DJ
Kantoff
Philip W
PW
D000368:Aged; D000369:Aged, 80 and over; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000494:pharmacology; D018450:Disease Progression; D004365:Drugs, Chinese Herbal; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010936:Plant Extracts / Q000008:administration & dosage* / Q000494:pharmacology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology
D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; C114209:herbal preparation PC-SPES; D017430:Prostate-Specific Antigen