Abstract |
Epidemiologic and animal studies suggest a protective role of green tea against breast cancer. However, the underlying mechanism is not understood. We conducted a randomized, double-blinded, placebo-controlled phase II clinical trial to investigate whether supplementation with green tea extract (GTE) modifies mammographic density (MD), as a potential mechanism, involving 1,075 healthy postmenopausal women. Women assigned to the treatment arm consumed daily 4 decaffeinated GTE capsules containing 1,315 mg total catechins, including 843 mg epigallocatechin-3-gallate (EGCG) for 12 months. A computer-assisted method (Madena) was used to assess MD in digital mammograms at baseline and month 12 time points in 932 completers (462 in GTE and 470 in placebo). GTE supplementation for 12 months did not significantly change percent MD (PMD) or absolute MD in all women. In younger women (50-55 years), GTE supplementation significantly reduced PMD by 4.40% as compared with the placebo with a 1.02% PMD increase from pre- to postintervention (P = 0.05), but had no effect in older women (Pinteraction = 0.07). GTE supplementation did not induce MD change in other subgroups of women stratified by catechol-O-methyltransferase genotype or level of body mass index. In conclusion, 1-year supplementation with a high dose of EGCG did not have a significant effect on MD measures in all women, but reduced PMD in younger women, an age-dependent effect similar to those of tamoxifen. Further investigation of the potential chemopreventive effect of green tea intake on breast cancer risk in younger women is warranted. Cancer Prev Res; 10(12); 710-8. ©2017 AACR.
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Authors | Hamed Samavat, Giske Ursin, Tim H Emory, Eunjung Lee, Renwei Wang, Carolyn J Torkelson, Allison M Dostal, Karen Swenson, Chap T Le, Chung S Yang, Mimi C Yu, Douglas Yee, Anna H Wu, Jian-Min Yuan, Mindy S Kurzer |
Journal | Cancer prevention research (Philadelphia, Pa.)
(Cancer Prev Res (Phila))
Vol. 10
Issue 12
Pg. 710-718
(Dec 2017)
ISSN: 1940-6215 [Electronic] United States |
PMID | 28904061
(Publication Type: Clinical Trial, Phase II, Journal Article, Randomized Controlled Trial)
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Copyright | ©2017 American Association for Cancer Research. |
Chemical References |
- Anticarcinogenic Agents
- Antioxidants
- Plant Extracts
- Tea
- Tamoxifen
- Catechin
- epigallocatechin gallate
- COMT protein, human
- Catechol O-Methyltransferase
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Topics |
- Aged
- Anticarcinogenic Agents
(pharmacology)
- Antioxidants
(administration & dosage)
- Body Mass Index
- Breast
(drug effects)
- Breast Density
(drug effects)
- Breast Neoplasms
(prevention & control)
- Catechin
(analogs & derivatives, pharmacology)
- Catechol O-Methyltransferase
(genetics)
- Dietary Supplements
- Double-Blind Method
- Female
- Genotype
- Humans
- Mammography
- Middle Aged
- Plant Extracts
(pharmacology)
- Postmenopause
- Tamoxifen
(pharmacology)
- Tea
(chemistry)
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