Phase 2
Completed N=1,075
Green Tea and Reduction of Breast Cancer Risk
Source: ClinicalTrials.gov NCT00917735 ↗Enrolled (actual)
1,075
Serious AEs
1.9%
Results posted
Feb 2016
Primary outcomePrimary: Mammographic Density — 22.71; 21.84; 22.09; 21.13 Percent
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.
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Mammographic Density |
22.71; 21.84; 22.09; 21.13 | — |
| PRIMARY Circulating Concentrations of Reproductive Hormones Including Estrone, Estradiol, Androstenedione, Testosterone, and Sex Hormone Binding Globulin (SHBG) |
22.8; 23.6; 22.5; 22.4; 3.4; 3.7 | — |
| PRIMARY Circulating Concentrations of IGF Axis Proteins Including IGF-1 and IGFBP-3 |
87.5; 88.3; 83.7; 83.1; 2048.0; 2047.6 | — |
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 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
Data sourced from ClinicalTrials.gov (NCT00917735). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication. Informational only — not medical advice.