Clinical trial · Interventional
Green Tea and Reduction of Breast Cancer Risk
Phase II, Randomized,Double-blind, Placebo-controlled, Study of the Efficacy of Green Tea Extract on Biomarkers of Breast Cancer Risk in High Risk Women With Differing Catechol-O-methyl Transferase (COMT) Genotypes
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
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.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
Interventions
Interventions (2)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Green tea extract supplement | Drug | — | UNRESOLVED |
| Placebo | Other | — | UNRESOLVED |
Design
Arms and outcomes
Arms (2)
- type
- EXPERIMENTAL
- label
- Green tea extract
- description
- Green tea extract capsules containing 80.7 % total catechins (51.7 % EGCG)
- interventionNames
- Drug: Green tea extract supplement
- type
- PLACEBO_COMPARATOR
- label
- Sugar pill
- description
- Placebo capsules containing 50% maltodextrin, 49.5 % cellulose, and 0.5 % magnesium stearate
- interventionNames
- Other: Placebo
Primary outcomes (3)
- measure
- Mammographic Density
- timeFrame
- Baseline and month 12
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 50 Years
- Maximum age
- 70 Years
Show eligibility criteria text
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
References
Publications (6)
- DERIVEDBathgate JR, Radler DR, Kurzer M, Samavat H. Green tea extract supplementation does not modify plasma concentration of F2-isoprostanes in women who are postmenopause: Findings from a randomized controlled trial. Nutr Res. 2023 May;113:29-38. doi: 10.1016/j.nutres.2023.03.001. Epub 2023 Mar 9. PMID 37011435
- DERIVEDSamavat H, Wu AH, Ursin G, Torkelson CJ, Wang R, Yu MC, Yee D, Kurzer MS, Yuan JM. Green Tea Catechin Extract Supplementation Does Not Influence Circulating Sex Hormones and Insulin-Like Growth Factor Axis Proteins in a Randomized Controlled Trial of Postmenopausal Women at High Risk of Breast Cancer. J Nutr. 2019 Apr 1;149(4):619-627. doi: 10.1093/jn/nxy316. PMID 30926986
- DERIVEDArikawa AY, Samavat H, Gross M, Kurzer MS. Plasma F2-isoprostanes Are Positively Associated with Glycemic Load, but Inversely Associated with Dietary Polyunsaturated Fatty Acids and Insoluble Fiber in Postmenopausal Women. J Nutr. 2017 Sep;147(9):1693-1699. doi: 10.3945/jn.117.254631. Epub 2017 Jul 26. PMID 28747487
- DERIVEDSamavat H, Newman AR, Wang R, Yuan JM, Wu AH, Kurzer MS. Effects of green tea catechin extract on serum lipids in postmenopausal women: a randomized, placebo-controlled clinical trial. Am J Clin Nutr. 2016 Dec;104(6):1671-1682. doi: 10.3945/ajcn.116.137075. Epub 2016 Nov 2. PMID 27806972
- DERIVEDDostal AM, Arikawa A, Espejo L, Kurzer MS. Long-Term Supplementation of Green Tea Extract Does Not Modify Adiposity or Bone Mineral Density in a Randomized Trial of Overweight and Obese Postmenopausal Women. J Nutr. 2016 Feb;146(2):256-64. doi: 10.3945/jn.115.219238. Epub 2015 Dec 23. PMID 26701796
- DERIVEDDostal AM, Samavat H, Espejo L, Arikawa AY, Stendell-Hollis NR, Kurzer MS. Green Tea Extract and Catechol-O-Methyltransferase Genotype Modify Fasting Serum Insulin and Plasma Adiponectin Concentrations in a Randomized Controlled Trial of Overweight and Obese Postmenopausal Women. J Nutr. 2016 Jan;146(1):38-45. doi: 10.3945/jn.115.222414. Epub 2015 Nov 18.