Green Tea and Reduction of Breast Cancer Risk
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Intervention: Green tea extract supplement; Placebo
Intervention description: 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
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 1075.0
Sex: Female
Minimum age: 50 Years
Maximum age: 70 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: Green tea; Breast cancer; Prevention; COMT genotype; EGCG (Epigallocatechin gallate); Mammographic density; Reproductive hormones; IGF axis proteins; Oxidative stress

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.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Signed informed consent

          -  Healthy postmenopausal women aged 50-70 years

          -  "Heterogeneously dense" (51-75% glandular) or "extremely dense" (>75%glandular)
             breasts

          -  Willing to avoid consumption of green tea for 1 year

        Exclusion Criteria:

          -  Positive serological markers of hepatitis B or hepatitis C infections

          -  Elevated levels of liver enzymes

          -  Recent (within 6 mo) or current hormone or hormone modification therapy, including
             systemic hormone replacement therapy, SERMS and aromatase inhibitors

          -  Current smoker of cigarettes or other tobacco products

          -  BMI <19 or >40 kg/m2

          -  Weight change > 10 lbs during the previous year

          -  History of breast cancer or proliferative breast disease

          -  Regular consumption of > 7 alcoholic drinks/wk

          -  Regular consumption of green tea (>1 cup/wk)

          -  Recent (within 6 mo) or current use of chemopreventive agents such as tamoxifen,
             raloxifene or aromatase inhibitors

          -  Participation in any weight loss or weight gain studies

          -  Currently taking Methotrexate or Enbrel

          -  History of ovarian cancer

          -  Any form of cancer in the last 5 years

          -  Presence of implants