A randomized controlled trial of green tea extract supplementation and mammographic density in postmenopausal women at increased risk of breast cancer

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

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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 ¼ 0.05), but had no effect in older women (Pinteraction ¼ 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.

Original languageEnglish (US)
Pages (from-to)710-718
Number of pages9
JournalCancer Prevention Research
Volume10
Issue number12
DOIs
StatePublished - Dec 1 2017

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Tea
Randomized Controlled Trials
Breast Neoplasms
Placebos
Breast Density
Catechol O-Methyltransferase
Phase II Clinical Trials
Catechin
Controlled Clinical Trials
Tamoxifen
Capsules
Epidemiologic Studies
Body Mass Index
Genotype

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A randomized controlled trial of green tea extract supplementation and mammographic density in postmenopausal women at increased risk of breast cancer. / Samavat, Hamed; Ursin, Giske; Emory, Tim H.; Lee, Eunjung; Wang, Renwei; Torkelson, Carolyn J.; Dostal, Allison M.; Swenson, Karen; Le, Chap T.; Yang, Chung S.; Yu, Mimi C.; Yee, Douglas; Wu, Anna H.; Yuan, Jian Min; Kurzer, Mindy S.

In: Cancer Prevention Research, Vol. 10, No. 12, 01.12.2017, p. 710-718.

Research output: Contribution to journalArticle

Samavat, Hamed ; Ursin, Giske ; Emory, Tim H. ; Lee, Eunjung ; Wang, Renwei ; Torkelson, Carolyn J. ; Dostal, Allison M. ; Swenson, Karen ; Le, Chap T. ; Yang, Chung S. ; Yu, Mimi C. ; Yee, Douglas ; Wu, Anna H. ; Yuan, Jian Min ; Kurzer, Mindy S. / A randomized controlled trial of green tea extract supplementation and mammographic density in postmenopausal women at increased risk of breast cancer. In: Cancer Prevention Research. 2017 ; Vol. 10, No. 12. pp. 710-718.
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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 ¼ 0.05), but had no effect in older women (Pinteraction ¼ 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.",
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AU - Samavat, Hamed

AU - Ursin, Giske

AU - Emory, Tim H.

AU - Lee, Eunjung

AU - Wang, Renwei

AU - Torkelson, Carolyn J.

AU - Dostal, Allison M.

AU - Swenson, Karen

AU - Le, Chap T.

AU - Yang, Chung S.

AU - Yu, Mimi C.

AU - Yee, Douglas

AU - Wu, Anna H.

AU - Yuan, Jian Min

AU - Kurzer, Mindy S.

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N2 - 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 ¼ 0.05), but had no effect in older women (Pinteraction ¼ 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.

AB - 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 ¼ 0.05), but had no effect in older women (Pinteraction ¼ 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.

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