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CompletedNCT00917735Updated Feb 22, 2016Results posted

Green Tea and Reduction of Breast Cancer Risk

A Phase 2 interventional study of Green tea extract supplement and Placebo in Breast Cancer, sponsored by University of Minnesota. Completed at 5 sites in United States. Open to female participants aged 50 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2016-02-22.

Sponsored by University of Minnesota · Phase 2, Interventional, and Prevention

Phase
Phase 2
Study type
Interventional
Enrollment
1,075
Allocation
Randomized
Ages
50 Years to 70 Years
Sex
Female
01

Study 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.

Read the 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.

02

Conditions studied

  • Breast Cancer

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Keywords

  • Green tea
  • Breast cancer
  • Prevention
  • COMT genotype
  • EGCG (Epigallocatechin gallate)
  • Mammographic density
  • Reproductive hormones
  • IGF axis proteins
  • Oxidative stress
03

In context

Breast Neoplasms

12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.

This study's enrollment of 1,075 is above the median of 72 across 9,302 interventional studies indexed under Breast Neoplasms.

Browse Breast Neoplasms studies →

Lead sponsor

University of Minnesota is the lead sponsor of 1,184 studies on the registry; 195 are open to participants now.

Of its 132 completed or terminated interventional studies of FDA-regulated products, 91 (69%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
50 Years to 70 Years
Sexes eligible
Female
Accepts healthy volunteers
Yes

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

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
05

Study design

Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
1,075 participants (actual)

Study arms

  • Experimental
    Green tea extract

    Green tea extract capsules containing 80.7 % total catechins (51.7 % EGCG)

    Drug: Green tea extract supplement

  • Placebo comparator
    Sugar pill

    Placebo capsules containing 50% maltodextrin, 49.5 % cellulose, and 0.5 % magnesium stearate

    Other: Placebo

Interventions

  • DrugGreen tea extract supplement

    Two green tea extract capsules twice daily after breakfast and dinner for one year

    Also known as: Green tea extract: Corban green tea blend (GTB-3D)

  • OtherPlacebo

    Two placebo capsules twice daily after breakfast and dinner for one year

    Also known as: Sugar Pill

06

What researchers measure

Primary outcomes

  1. Mammographic Density

    Percent mammographic density was measured on digital images using a computer-assisted and quantitative method.

    Time frame: Baseline and month 12

  2. Circulating Concentrations of Reproductive Hormones Including Estrone, Estradiol, Androstenedione, Testosterone, and Sex Hormone Binding Globulin (SHBG)

    Circulating levels of reproductive hormones including estrone, estradiol, androstenedione, testosterone and SHBG were measured in fasting blood samples by liquid chromatography/tandem mass spectrometry method.

    Time frame: Baseline and month 12

  3. Circulating Concentrations of IGF Axis Proteins Including IGF-1 and IGFBP-3

    Circulating levels of IGF-1 and IGFBP-3 were measured in fasting blood samples by ELISA method.

    Time frame: Baseline and month 12

07

Results

Posted Feb 22, 2016
Limitations and caveats
We had limited success in recruiting minority populations.

Participant flow

August 2009 through April 2013

Participant flow — Overall Study
MilestoneGreen Tea ExtractSugar Pill
Started538537
Completed463474
Not completed7563

Outcome measures

PrimaryMammographic Density

Percent mammographic density was measured on digital images using a computer-assisted and quantitative method.

Time frame:
Baseline and month 12
Reported as:
Geometric mean · Percent
Mammographic Density
PercentGreen Tea ExtractSugar Pill
Percent mammographic density at baseline22.71 (21.39 to 24.10)21.84 (20.59 to 23.17)
Percent mammographic density at month 1222.09 (20.77 to 23.50)21.13 (19.88 to 22.47)
PrimaryCirculating Concentrations of Reproductive Hormones Including Estrone, Estradiol, Androstenedione, Testosterone, and Sex Hormone Binding Globulin (SHBG)

Circulating levels of reproductive hormones including estrone, estradiol, androstenedione, testosterone and SHBG were measured in fasting blood samples by liquid chromatography/tandem mass spectrometry method.

Time frame:
Baseline and month 12
Reported as:
Geometric mean · pg/ml
Circulating Concentrations of Reproductive Hormones Including Estrone, Estradiol, Androstenedione, Testosterone, and Sex Hormone Binding Globulin (SHBG)
pg/mlGreen Tea ExtractSugar Pill
Circulating estrone at baseline22.8 (21.6 to 24.0)23.6 (22.4 to 24.9)
Circulating estrone at month 1222.5 (21.3 to 23.7)22.4 (21.3 to 23.6)
Circulating estradiol at baseline3.4 (3.1 to 3.8)3.7 (3.3 to 4.1)
Circulating estradiol at month 123.7 (3.4 to 4.1)3.1 (2.8 to 3.5)
Circulating androstenedione at baseline479.8 (459.4 to 501.2)507.2 (485.9 to 529.5)
Circulating androstenedione at month 12468.8 (450.2 to 488.3)479.5 (460.6 to 499.1)
Circulating testosterone at baseline151.0 (142.7 to 159.7)161.6 (152.8 to 170.8)
Circulating testosterone at month 12158.1 (149.9 to 166.9)155.1 (147.1 to 163.6)
Circulating SHBG at baseline68.1 (65.0 to 71.3)69.1 (66.0 to 72.3)
Circulating SHBG at month 1268.7 (65.5 to 72.0)68.7 (65.5 to 72.0)
PrimaryCirculating Concentrations of IGF Axis Proteins Including IGF-1 and IGFBP-3

Circulating levels of IGF-1 and IGFBP-3 were measured in fasting blood samples by ELISA method.

Time frame:
Baseline and month 12
Reported as:
Geometric mean · ng/ml
Circulating Concentrations of IGF Axis Proteins Including IGF-1 and IGFBP-3
ng/mlGreen Tea ExtractSugar Pill
Circulating IGF-1 at baseline87.5 (85.3 to 89.8)88.3 (86.1 to 90.5)
Circulating IGF-1 at month 1283.7 (81.6 to 85.8)83.1 (81.0 to 85.2)
Circulating IGFBP-3 at baseline2048.0 (2008.9 to 2088.0)2047.6 (2008.9 to 2087.1)
Circulating IGFBP-3 at month 122048.1 (2008.0 to 2089.1)2040.7 (2001.0 to 2081.0)

Adverse events

Collected over 5 years. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Green Tea Extract—12/538 (2.2%)407/538 (75.7%)
Sugar Pill—8/537 (1.5%)391/537 (72.8%)
Most frequent serious events
Most frequent serious events
EventGreen Tea ExtractSugar Pill
Elevated ALT or AST enzymeHepatobiliary disorders7/5380/537
SurgerySurgical and medical procedures3/5382/537
Diagnosis of Uterine CancerNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/5382/537
Motorcycle accidentSocial circumstances0/5381/537
HypertensionBlood and lymphatic system disorders0/5381/537
DiarrheaGastrointestinal disorders0/5381/537
FallSocial circumstances0/5381/537
Acoustic NeuromaEar and labyrinth disorders1/5380/537
ColitisGastrointestinal disorders1/5380/537
Most frequent other events
Most frequent other events
EventGreen Tea ExtractSugar Pill
OtherGeneral disorders280/538218/537
NauseaGastrointestinal disorders235/538184/537
InfectionsInfections and infestations216/538217/537
VascularVascular disorders154/538144/537
RespitoryRespiratory, thoracic and mediastinal disorders122/538122/537
GeneralGeneral disorders69/53877/537
MusuclarMusculoskeletal and connective tissue disorders65/53869/537

Baseline characteristics

Age, Continuous
Age, Continuous(years)Green Tea ExtractSugar PillTotal
Mean59.9 ± 5.059.6 ± 5.159.8 ± 5.02
Sex: Female, Male
Sex: Female, Male(Participants)Green Tea ExtractSugar PillTotal
Female5385371075
Male000
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Green Tea ExtractSugar PillTotal
Hispanic or Latino5611
Not Hispanic or Latino5165101026
Unknown or Not Reported172138
Race (NIH/OMB)
Race (NIH/OMB)(Participants)Green Tea ExtractSugar PillTotal
American Indian or Alaska Native000
Asian3710
Native Hawaiian or Other Pacific Islander000
Black or African American4711
White5155051020
More than one race426
Unknown or Not Reported121628
Region of Enrollment
Region of Enrollment(participants)Green Tea ExtractSugar PillTotal
United States5385371075
Height
Height(cm)Green Tea ExtractSugar PillTotal
Mean163.5 ± 6.3164.3 ± 6.2163.9 ± 6.2
Weight
Weight(kg)Green Tea ExtractSugar PillTotal
Mean67.4 ± 10.667.9 ± 10.567.4 ± 10.5
Waist-to-hip ratio
Waist-to-hip ratio(Ratio)Green Tea ExtractSugar PillTotal
Mean0.84 ± 0.10.83 ± 0.10.83 ± 0.07
08

Study locations

5 sites
  • Fairview Southdale Breast Center
    Edina, Minnesota 55435, United States
  • Fairview Maple Grove Breast Center
    Maple Grove, Minnesota 55369, United States
  • University of Minnesota Medical Center (UMMC) Breast Clinic
    Minneapolis, Minnesota 55455, United States
  • Park Nicollet Institute
    St. Louis Park, Minnesota 55426, United States
  • Food Science and Nutrition, University of Minnesota
    St. Paul, Minnesota 55108, United States
09

References and documents

Publications

  • Samavat 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. PubMed 30926986 ↗
  • Arikawa 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. PubMed 28747487 ↗
  • Samavat 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. PubMed 27806972 ↗
  • Dostal 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. PubMed 26701796 ↗
  • Dostal 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. PubMed 26581683 ↗
10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Feb 22, 2016, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT00917735
Lead sponsor
University of Minnesota
Collaborators
National Cancer Institute (NCI)
Responsible party
Sponsor
First posted
Jun 10, 2009
Start date
Jul 2009
Primary completion
Jun 2014
Completion
Jun 2014
Results posted
Feb 22, 2016
Last update
Feb 22, 2016

Study contacts

Mindy S Kurzer, Ph.D
principal investigator · University of Minnesota

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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