title: Soy isoflavones in the treatment of prostate cancer.
abstract: Epidemiological studies suggest an inverse association between soy intake and prostate cancer (Pca) risk. We have previously observed that soy isoflavone genistein induces apoptosis and inhibits growth of both androgen-sensitive and androgen-independent Pca cells in vitro. To determine the clinical effects of soy isoflavones on Pca we conducted a pilot study in patients with Pca who had rising serum prostate-specific antigen (PSA) levels. Patients with Pca were enrolled in the study if they had either newly diagnosed and untreated disease under watchful waiting with rising PSA (group I) or had increasing serum PSA following local therapy (group II) or while receiving hormone therapy (group III). The study intervention consisted of 100 mg of soy isoflavone (Novasoy) taken by mouth twice daily for a minimum of 3 or maximum of 6 mo. Forty-one patients were enrolled (4 in group I, 18 in group II, and 19 in group III) and had a median PSA level of 13.3 ng/ml. Thirty-nine patients could be assessed for response. Soy isoflavone supplementation was given for a median of 5.5 (range 0.8-6) mo per patient. Although there were no sustained decreases in PSA qualifying for a complete or partial response, stabilization of the PSA occurred in 83% of patients in hormone-sensitive (group II) and 35% of hormone-refractory (group III) patients. There was a decrease in the rate of the rise of serum PSA in the whole group (P = 0.01) with rates of rise decreasing from 14 to 6% in group II (P = 0.21) and from 31 to 9% in group III (P = 0.05) following the soy isoflavone intervention. Serum genistein and daidzein levels increased during supplementation from 0.11 to 0.65 microM (P = 0.00002) and from 0.11 to 0.51 microM (P = 0.00001), respectively. No significant changes were observed in serum levels of testosterone, IGF-1, IGFBP-3, or 5-OHmdU. These data suggest that soy isoflavones may benefit some patients with Pca.
authors.affiliation: Division of Hematology and Oncology, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Maha
authors.initials: M
authors.lastname: Hussain
authors.forename: Mousumi
authors.initials: M
authors.lastname: Banerjee
authors.forename: Fazlul H
authors.initials: FH
authors.lastname: Sarkar
authors.forename: Zora
authors.initials: Z
authors.lastname: Djuric
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.forename: Daniel
authors.initials: D
authors.lastname: Doerge
authors.forename: Joseph
authors.initials: J
authors.lastname: Fontana
authors.forename: Sreenivasa
authors.initials: S
authors.lastname: Chinni
authors.forename: Joanne
authors.initials: J
authors.lastname: Davis
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Forman
authors.forename: David P
authors.initials: DP
authors.lastname: Wood
authors.forename: Omer
authors.initials: O
authors.lastname: Kucuk
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000097:blood*; D019587:Dietary Supplements; D018450:Disease Progression; D019833:Genistein / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010865:Pilot Projects; D017430:Prostate-Specific Antigen / Q000097:blood / Q000187:drug effects*; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D013025:Glycine max / Q000009:adverse effects / Q000737:chemistry; D013739:Testosterone / Q000097:blood
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D007529:Isoflavones; D013739:Testosterone; C004742:daidzein; D019833:Genistein; D017430:Prostate-Specific Antigen