Green Tea and Reduction of Breast Cancer Risk
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Study type: Interventional
Phase: Phase 2

Summary: 
      RATIONALE: Green tea extract contains ingredients (catechins) that may lower the risk of
      breast cancer.

      PURPOSE: This phase II trial is studying how well green tea extract works in preventing
      breast cancer compared to a placebo in postmenopausal women with high breast density.

      The investigators have hypothesized that green tea consumption reduces breast cancer risk,
      and this effect is seen primarily in women who have the low-activity COMT genotype. The
      investigators will test this by evaluating the effects of green tea extract on breast cancer
      biomarkers including mammographic density, plasma insulin-like growth factor 1 (IGF-1), IGF
      binding protein 3 (IGFBP-3), estrone, estradiol, androstenedione, sex hormone binding
      globulin (SHBG), urinary estrogen metabolites and plasma F2-isoprostanes.
    

Detailed description: 
      OBJECTIVES:

        1. Primary:

           1.1 To determine the effects of green tea extract consumption (containing 800 mg EGCG
           per day) for 12 months on the following recognized biomarkers of breast cancer risk:

             1. Mammographic density

             2. Circulating concentrations of insulin-like growth factor 1 (IGF-1) and IGF binding
                protein 3 (IGFBP-3)

             3. Circulating concentrations of reproductive hormones (estrone, estradiol,
                androstenedione) and sex hormone binding globulin (SHBG)

           1.2 To determine the effects of COMT genotype on the green tea extract effects described
           above.

        2. Secondary:

      2.1 To determine the effects of green tea extract consumption (containing 800 mg EGCG per
      day) for 12 months on the following hypothesized biomarkers of breast cancer risk:

        1. Urinary estrogen metabolites (estrone, estradiol, and their 2-hydroxy, 4-hydroxy,
           2-methoxy, and 4-methoxy metabolites, estriol, and 16- hydroxyestrone)

        2. Circulating concentrations of F-2 isoprostanes, a recognized biomarker of systemic
           oxidative stress

      2.2 To determine the effects of COMT genotype on the green tea extract effects described
      above.

      2.3 To determine the effects of COMT genotype on catechin metabolism and excretion, as
      measured by circulating and urinary concentrations.
    

Intervention name(s): Green tea extract supplement; Placebo
Intervention type(s): Drug; Other
Intervention description(s): Two green tea extract capsules twice daily after breakfast and dinner for one year; Two placebo capsules twice daily after breakfast and dinner for one year
Other intervention name(s): Green tea extract: Corban green tea blend (GTB-3D); Sugar Pill
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Green tea; Breast cancer; Prevention; COMT genotype; EGCG (Epigallocatechin gallate); Mammographic density; Reproductive hormones; IGF axis proteins; Oxidative stress