Green tea and breast density in endangered postmenopausal women

Green tea has a good security profile, a long historical use, a growing number of positive clinical studies and is generally well tolerated. It could continue to be a promising supplement in breast cancer prevention.

The starting characteristics of the study participants (N = 932) were evenly distributed between the GTE and the placebo group. The middle (SD) initial age was 59.8 (± 5.0) years. The middle (SD) BMI was 25.1 (± 3.7). The majority of the participants had a certain university degree, was a non -smoker and pars; The vast majority (97%) were non-Hispanic white women.

The basic values ​​for energy, food and nutrients were similar between the treatment groups, although a higher intake of vitamin supplements was determined compared to the placebo participants ( p = 0.038).

Intervention

green tea extract (decaffeinated) in capsule form, each capsule contains a total of 328.8 mg of catechins, 210.7 mg epigallocatechin-3 gallery (EGCG) and less than 4 mg caffeine; The participants consumed 4 capsules per day for 12 months with a total of around 1,315 mg total catechins, 843 mg EGCG and less than 16 mg total caffeine (corresponds to 5 brewed 8-uncounters-cups decaffeinated green teas) per day.

study parameters evaluated

Each participant had a mammography at the beginning of the course (month 0) and month 12 to assess MD before and after the intervention. At the beginning of the study, extensive questionnaires were filled out about anamnesis, which contained questions about lifestyle, demography, taking medication and nutritional supplements as well as medical and reproductive history. Questionnaires on nutritional history were filled out at the beginning of the course and at the end of the intervention. The liver function and possible undesirable events were closely monitored throughout the intervention. During the screening visit before the intervention CONT , genotyping was carried out, together with non-sober blood tests, vital functions and anthropometric measurements. Other biomarkers for breast cancer, including plasma insulin-like growth factor 1 (IGF-1), IGF-binding protein 3 (IGFBP-3), Östron, Östradiol, androstonion, sex hormone-binding globulin (SHBG), estrogen metabolites in urine and plasma F2-isoprostane were also evaluated.

The mammographical density is calculated by dividing the dense surface of the breast, the so -called absolute density, through the entire chest area. It is specified in percent and can be referred to as a percent MD (PMD).

Primary result measurements

Change of the PMD compared to the initial value at the end of the 12-month intervention.

This study was part of a larger study that, in addition to MD, also rated the circulating concentrations of IGF-1, IGFBP-3, reproductive hormones (Östron, estradiol, Androstendion) and SHBG as primary endpoints; and the effects of the COMT genotype on GTE effects.

important knowledge

Overall, the 12-month daily GTE intake reduced the PMD or the absolute mammographic density compared to placebo after adaptation for age (at the beginning of the course) and the BMI (at the beginning of the course and in month 12). In women between the ages of 50 and 55, however, a 12-month daily GTE supplement significantly reduced the PMD, which led to a removal of the PMD by 4.40 %, compared to those who received placebo that were increasing by 1.02 % ( p for difference = 0.05). A statistically borderline significant result ( p interaction = 0.07) was observed during the interaction between age and GTE supplementation in the event of PMD change. Other factors, including BMI, years since menopause, alcohol, parity and status of drinking tea, showed no modifying effect on the PMD when taking GTE.

The people in the placebo group experienced a significant reduction in vitamin C intake compared to the GTE group ( p = 0.045), but weight, BMI and energy/food intake remained stable in both groups during the 12-month study.

practice implications

In 2018, an estimated 266,120 cases of breast cancer will be diagnosed in the United States, which makes it the most frequently diagnosed cancer in all sexes and accounts for 15.3 % of all new cancer cases. ^{2 While almost 90 % of the persons diagnosed with breast cancer 5 years after the diagnosis are still valued in 2018 the United States die from the disease. It is estimated that breast cancer is diagnosed in 12.4 % of women in the USA for some time in their lives, based on data from 2013-2015.}

The mammographical density reflects the relative ratio of fibroglandular tissue to fat tissue in the chest and serves as an established predictor for breast cancer risk. reported that a 2 % higher risk of breast cancer is accompanied by 1 %. ^{3 In an intervention study, it was shown that taking postmenopausal hormones increased the MD by 4.7 % after 12-month use, which may lead to an increase in breast cancer risk by 9.4 % could. 4}

The decrease in the MD observed in the present study could lead to a reduction in breast cancer risk by 8.8 % for women aged 50 to 55, which GTE consumed for a year. Interestingly, Cuzick et al. al. that Tamoxifen reduced the MD by 13.4 % (95 % confidence interval) after 54 months of treatment [CI]: 8.6-18.1) in women aged 45 or disciples; For over 55-year-olds, the MD had only dropped by 1.1 % with the same intervention and the same time frame. Whether a GTE supplement in women aged 45 or younger would lead to a similar reduction in the MD compared to Tamoxifen for 54 months is still being investigated, but is certainly of interest. In a similar way, would a GTE supplement over 1 year lead to women aged 55 or disciples to an additional reduction in the MD? We don't know yet, but the fascinating results of the GTE study justify additional studies on these questions.

A study from 2007, published in the New England Journal of Medicine found that women with more than 75 % MD had an increased risk of breast cancer compared to women with less than 10 % MD (ODDS Ratio [or]: 4.7; 95 % AI: 3.0–7.4), whereby the risk was particularly high for women under 56 years. In this group, 26 % of all breast cancer cases and 50 % of cancer that were discovered within 12 months of negative screening were due to an MD of 50 % or more. ^{5 In view of PMD's value in the prediction of a woman to develop breast cancer, health service providers should be involved in reducing breast density when they Develop strategies to reduce breast cancer risk.}

The study examined in this review has special relevance for women between the ages of 50 and 55, which have an increased risk of breast cancer due to an increased breast density. Green tea has a good security profile, a long historical use, a growing number of positive clinical studies and is generally well tolerated. It could continue to be a promising addition to breast cancer prevention. It would be great to see whether further studies could replicate the results of this study. It would also be helpful to have a more ethnic and racial population in future studies so that the results are generalized for our diverse population and reflect them.