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Phase II trial of isoflavone in prostate-specific antigen recurrent prostate cancer after previous local therapy.

Pendleton JM, Tan WW, Anai S, Chang M, Hou W, Shiverick KT, Rosser CJ - BMC Cancer (2008)

Bottom Line: Specifically, the slope of PSA after study entry was significantly lower than that before study entry in 6 patients and the slope of PSA after study entry was significantly higher than before study entry in 2 patients.For the remaining 12 patients, the change in slope was statistically insignificant.Nearly two thirds of the patients were noted to have significant levels of free equol in their serum while on therapy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Urology, The University of Florida, Jacksonville, Florida 32209, USA. john.pendleton@jax.ufl.edu

ABSTRACT

Background: Data exist that demonstrate isoflavones' potent antiproliferative effects on prostate cancer cells. We evaluated the efficacy of isoflavone in patients with PSA recurrent prostate cancer after prior therapy. We postulated that isoflavone therapy would slow the rate of rise of serum PSA.

Methods: Twenty patients with rising PSA after prior local therapy were enrolled in this open-labeled, Phase II, nonrandomized trial (Trial registration # NCT00596895). Patients were treated with soy milk containing 47 mg of isoflavonoid per 8 oz serving three times per day for 12 months. Serum PSA, testosterone, lipids, isoflavone levels (genistein, daidzein, and equol), and quality of life (QOL) were measured at various time points from 0 to 12 months. PSA outcome was evaluated.

Results: Within the mixed regression model, it was estimated that PSA had increased 56% per year before study entry and only increased 20% per year for the 12-month study period (p = 0.05). Specifically, the slope of PSA after study entry was significantly lower than that before study entry in 6 patients and the slope of PSA after study entry was significantly higher than before study entry in 2 patients. For the remaining 12 patients, the change in slope was statistically insignificant. Nearly two thirds of the patients were noted to have significant levels of free equol in their serum while on therapy.

Conclusion: Dietary intervention with isoflavone supplementation may have biologic activity in men with biochemical recurrent prostate cancer as shown by a decline in the slope of PSA. This study may lend support to the literature that nutritional supplements have biologic activity in prostate cancer and therefore, further studies with these agents in randomized clinical trials should be encouraged.

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Effect of PSA vs. CAG Polymorphism MW over Time. MW, molecular weight.
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Figure 2: Effect of PSA vs. CAG Polymorphism MW over Time. MW, molecular weight.

Mentions: There were 9 documented AR gene CAG polymorphisms in our cohort (Table 3). Eight men had ≤ 20 CAG repeat. A longer CAG polymorphism was associated with a lower PSA level at 12 months after study entry (Spearman's correlation coefficient = -0.63, p = 0.05) and a slower rise in PSA over time (Figure 2).


Phase II trial of isoflavone in prostate-specific antigen recurrent prostate cancer after previous local therapy.

Pendleton JM, Tan WW, Anai S, Chang M, Hou W, Shiverick KT, Rosser CJ - BMC Cancer (2008)

Effect of PSA vs. CAG Polymorphism MW over Time. MW, molecular weight.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2394534&req=5

Figure 2: Effect of PSA vs. CAG Polymorphism MW over Time. MW, molecular weight.
Mentions: There were 9 documented AR gene CAG polymorphisms in our cohort (Table 3). Eight men had ≤ 20 CAG repeat. A longer CAG polymorphism was associated with a lower PSA level at 12 months after study entry (Spearman's correlation coefficient = -0.63, p = 0.05) and a slower rise in PSA over time (Figure 2).

Bottom Line: Specifically, the slope of PSA after study entry was significantly lower than that before study entry in 6 patients and the slope of PSA after study entry was significantly higher than before study entry in 2 patients.For the remaining 12 patients, the change in slope was statistically insignificant.Nearly two thirds of the patients were noted to have significant levels of free equol in their serum while on therapy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Urology, The University of Florida, Jacksonville, Florida 32209, USA. john.pendleton@jax.ufl.edu

ABSTRACT

Background: Data exist that demonstrate isoflavones' potent antiproliferative effects on prostate cancer cells. We evaluated the efficacy of isoflavone in patients with PSA recurrent prostate cancer after prior therapy. We postulated that isoflavone therapy would slow the rate of rise of serum PSA.

Methods: Twenty patients with rising PSA after prior local therapy were enrolled in this open-labeled, Phase II, nonrandomized trial (Trial registration # NCT00596895). Patients were treated with soy milk containing 47 mg of isoflavonoid per 8 oz serving three times per day for 12 months. Serum PSA, testosterone, lipids, isoflavone levels (genistein, daidzein, and equol), and quality of life (QOL) were measured at various time points from 0 to 12 months. PSA outcome was evaluated.

Results: Within the mixed regression model, it was estimated that PSA had increased 56% per year before study entry and only increased 20% per year for the 12-month study period (p = 0.05). Specifically, the slope of PSA after study entry was significantly lower than that before study entry in 6 patients and the slope of PSA after study entry was significantly higher than before study entry in 2 patients. For the remaining 12 patients, the change in slope was statistically insignificant. Nearly two thirds of the patients were noted to have significant levels of free equol in their serum while on therapy.

Conclusion: Dietary intervention with isoflavone supplementation may have biologic activity in men with biochemical recurrent prostate cancer as shown by a decline in the slope of PSA. This study may lend support to the literature that nutritional supplements have biologic activity in prostate cancer and therefore, further studies with these agents in randomized clinical trials should be encouraged.

Show MeSH
Related in: MedlinePlus