Green tea extract contains ingredients that may prevent or slow the growth of prostate cancer. This phase I trial is studying how well green tea extract works in treating patients with prostate cancer undergoing surgery to remove the prostate
PRIMARY OBJECTIVES: I. Determine the bioavailability of defined green tea catechin extract in prostate tissue after treatment with defined green tea extract in patients with prostate cancer. SECONDARY OBJECTIVES: I. Determine the effect of this treatment on changes in clusterin levels and matrix metalloproteinase (MMP)-2 and MMP-9 in prostate tissue from these patients. II. Determine the effect of this treatment on changes in serum insulin-like growth factor (IGF)-1 and IGF binding protein-3 in these patients. III. Determine the effect of this treatment on changes in oxidative DNA damage in peripheral blood leukocytes in these patients. OUTLINE: This is a randomized, double-blind, placebo-controlled study. Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive oral defined green tea catechin extract daily for 4-7 weeks. Arm II: Patients receive oral placebo daily for 4-7 weeks. All patients undergo surgery one day after the last dose of study agent. Biopsies are taken at the time of surgery. Plasma and tissue catechin levels are measured with high performance liquid chromatography (HPLC). 8OHdG levels in peripheral blood are measured with HPLC and mass spectometry. Immunohistochemistry is used to measure matrix metalloproteinase (MMP)-2, MMP-9, and clusterin. Insulin-like growth factor (IGF)-1 and IGF binding protein-3 are measured with immunoenzyme techniques.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
50
Given orally
Given orally
Correlative studies
Arizona Cancer Center - Tucson
Tucson, Arizona, United States
Post-treatment green tea catechin concentration levels in prostate tissue
Descriptive statistics will be performed on prostate tissue EGCG within each intervention group. The difference in concentration levels between the two intervention groups will be tested using a two-group t-test at a one-sided 0.05 level of significance. If the distributions are not symmetrical, a non-parametric Wilcoxon test will be considered. The percentage of patients positive for EGCG in prostate tissue will be compared between the intervention groups using a Fisher's exact test of proportions at a one-sided 0.05 level of significance.
Time frame: Up to 6 weeks
Changes in clusterin, matrix metalloproteinase (MMP)-2, and MMP-9 levels
Will be compared between intervention groups using a two-group t-test with a 0.05 two-sided significance level; with a sample size of 23 patients per group, there will be over 90% power to detect a difference equal to an effect size of 1.0. If the distributions are not symmetrical, a non-parametric Wilcoxon test will be considered. Correlations among the various biomarkers, as well as between post-intervention EGCG concentrations and changes in biomarker levels, will be explored (using Pearson or Spearman Rank correlation coefficients as appropriate).
Time frame: Baseline to post-treatment
Changes in Serum levels of insulin-like growth factor (IGF)-1 and IGF binding protein-3
Will be compared between intervention groups using a two-group t-test with a 0.05 two-sided significance level; with a sample size of 23 patients per group, there will be over 90% power to detect a difference equal to an effect size of 1.0. If the distributions are not symmetrical, a non-parametric Wilcoxon test will be considered. Correlations among the various biomarkers, as well as between post-intervention EGCG concentrations and changes in biomarker levels, will be explored (using Pearson or Spearman Rank correlation coefficients as appropriate).
Time frame: Baseline to post-treatment
Change in ratio of 8OHdG:dG
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Correlative studies
Correlative studies
Undergo biopsy
Correlative studies
Correlative studies
Statistical analysis will focus on the change scores (defined as changes from baseline to post-intervention). Changes in the Polyphenon E group will be compared with those in the placebo group, using a two-sided t-test.
Time frame: Baseline to post-treatment
Change in plasma levels of EGCG
Will be compared between groups, and the correlation of plasma and prostate tissue levels will be examined; however, plasma levels are expected to be low because of the washout during pre-operative fasting. Additional exploratory analyses will investigate the correlation of EGCG tissue levels with adherence during the intervention period (assessed primarily by capsule counts).
Time frame: Baseline to post-treatment