Why Some Cancers Are Difficult To Treat
Breast cancer is the most common malignancy in women, with a quarter of a million diagnosed every year. And it is the second leading cause of cancer death in women, killing more than 40,000.2
There are numerous types of breast cancer, some of which are more difficult to treat than others.
Estrogen receptor positive cancers are easier to treat because they have estrogen receptors on their surface. Tamoxifen can bind to the estrogen receptor and prevent estrogen from stimulating the growth of cancer cells.3-5
The problem is that some originally ER positive cells lose these receptors during cancer development, turning them into estrogen receptor negative cells.
Without estrogen receptors, hormone treatments like tamoxifen are not effective. This deprives its victims from an effective form of treatmentand condemns them to much higher risks of death.
New science has discovered that green tea and broccoli contain compounds that can restore the estrogen receptors in ER negative cells.
These findings may make these difficult-to-treat-cancers easier to destroy by anti-estrogen therapies.
Does The National Cancer Institute Recommend The Use Of Tea To Prevent Cancer
NCI is a research institution. It develops evidence-based research results for others to interpret. In general, therefore, NCI does not make recommendations about specific medical or dietary interventions.
Moreover, as noted above, the evidence regarding the potential benefits of tea consumption in relation to cancer is inconclusive at present.
Selected References
Seeram NP, Henning SM, Niu Y, et al. Catechin and caffeine content of green tea dietary supplements and correlation with antioxidant capacity. Journal of Agricultural and Food Chemistry 2006 54:15991603.
What Evidence From Human Studies Links Tea To Cancer Prevention
Tea has long been regarded as an aid to good health, and many believe it can help reduce the risk of cancer. Most studies of tea and cancer prevention have focused on green tea . Although tea and/or tea polyphenols have been found in animal studies to inhibit tumorigenesis at different organ sites, including the skin, lung, oral cavity, esophagus, stomach, small intestine, colon, liver, pancreas, and mammary gland , the results of human studiesboth epidemiologic and clinical studieshave been inconclusive.
Epidemiologic Studies
More than 50 epidemiologic studies of the association between tea consumption and cancer risk have been published since 2006. The results of these studies have often been inconsistent, but some have linked tea consumption to reduced risks of cancers of the colon, breast, ovary, prostate, and lung . The inconsistent results may be due to variables such as differences in tea preparation and consumption, the types of tea studied , the methods of tea production, the bioavailability of tea compounds, genetic variation in how people respond to tea consumption, the concomitant use of tobacco and alcohol, and other lifestyle factors that may influence a persons risk of developing cancer, such as physical activity or weight status.
Clinical Trials
Several clinical trials have investigated the role of tea and tea polyphenols in cancer prevention . However, few trials have examined the effects of tea or tea polyphenols on cancer incidence or mortality.
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What You Need To Know
Some forms of breast cancer are more difficult to treat than others. Breast cancers that are estrogen receptor positive respond better to common treatment, however many of these cancers mutate and lose their estrogen receptors. Compounds found in broccoli and green tea utilize several mechanisms to reduce breast cancer severity and risk. New research shows that they can also create estrogen receptors on cancers cells.
What Is Green Tea
China and Japan have used green tea as a medicine for many years. The tea is made from the steamed, unfermented leaves of the Camellia sinensis plant. It is also called Chinese tea.
Manufacturers promote it as a dietary supplement. They claim that it helps control:
People also drink it because they believe it might prevent certain types of cancer.
The substance in green tea that researchers think is most helpful is a catechin. It is called epigallocatechin-3-gallate . It also contains caffeine and theanine.
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Green Tea And Metastasis Of Liver Cancer
Hepatocellular carcinoma is a growing health problem worldwide and only few promising treatment options are available at present, stressing the urgent need for novel therapeutic approaches. The effect of a nutrient mixture containing lysine, proline, arginine, ascorbic acid, and green tea extract on tumor growth and hepatic metastasis were investigated in athymic nude male mice inoculated with 10 B16FO melanoma cells. Metastasis was studied in C57BL/6 mice receiving melanoma cells by intrasplenic injection, as well as a regular or 0.5% nutrient mixture-supplemented diet for 2 weeks. Nutrient mixture inhibited the growth of melanoma cells, and the lesions were consistent with malignant melanoma. Mice were also injected with melanoma cells in the spleen. Control group animals developed large black spleens and livers indicating growth in the spleen and metastasis to the liver, while mice supplemented with nutrient mixture showed less growth in spleen and reduced metastasis to the liver. The survival time was also greater in mice receiving nutrient mixture supplementation than animals on the regular diet .
Green Tea And Reduction Of Breast Cancer Risk And Recurrence By Dr Tori Hudson Nd
As clinicians, you likely already know of the many health benefits of green tea, and likely some of you are already familiar with some of the research on green tea and breast cancer risk reduction and recurrence. Based on a study some years back, I have been advising women with stage I and II breast cancer to drink 5 cups/day or take a select number of capsules per day . This current meta-analysis is a good update on the topic. The purpose of this systematic review and meta-analysis was to evaluate green tea consumption and breast cancer risk, recurrence and risk in relationship to menopause status.
A literature search was done following current Systematic Review and Meta-Analysis guidelines, and using 3 search systems . Observational studies that evaluated breast cancer risk in adult women were included and selected studies evaluated green tea consumption using a questionnaire or interview. A total of 194 studies were detected but of those 39 were duplicate studies and 115 did not meet the inclusion criteria. Another 25 studies were excluded because there was insufficient differentiation between the types of teas that were consumed and 2 studies were excluded due to data insufficiencies. That left 13 studies that were included in this meta-analysis. Seven were conducted in Japan, five in China and one in the U.S.
Reference:
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Synergistic Enhancement Of Anticancer Activity Against Human Cancer Cell Lines With The Combination Of Egcg And Anticancer Compounds
In 2011, Suganumas group published a review article entitled New cancer treatment strategy using combination of green tea catechins and anticancer drugs in Cancer Sci. . The Publisher, Wiley-Blackwell at the Annual Meeting of Japanese Cancer Association, announced that our review article was No. 1 among most read articles and No. 2 among most cited articles in 2012. Since then, numerous scientists around the world have become greatly interested in the combination. We briefly showed that the combinations of EGCG or other green tea catechins and 46 anticancer drugs all synergistically induced in vitro anticancer effects in 58 human cancer cell lines .
Outcome: Bc Diagnosis And Bc Recurrences
Seven studies focused on the risk of BC recurrence : one was conducted in USA, three in China, and the remaining in Japan. In three of these studies, the ESs indicated a potential protective effect of BC recurrence, while in the other four papers, the reduction was not statistically significant. The pooled ES was 0.81 , p-value = 0.000) based on a total of 13,956 participants, with participant numbers in individual studies ranging from 472 to 6928 participants . A slight statistical heterogeneity was found . The funnel plot shows no potential publication bias, which was confirmed by Eggers linear regression test .
Forest plot of the meta-analysis comparing green tea consumption in breast cancer . Funnel plot . Abbreviations: ES = effect size CI = confidence interval W = weight Sig = significance N= number.
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Green Tea And Metastasis Of Breast Cancer
Metastasis of breast cancer is the major reason for the high mortality of breast cancer patients and is directly linked to the invasive behavior of breast cancer cells. Cancer metastasis consists of several interdependent processes including cancer cell adhesion, cancer cell migration, and invasion of cancer cells. Recently, the effects of EGCG treatment on growth and invasion in a breast carcinoma cell line resistant to tamoxifen and parental MCF-7 were reported. Treatment with EGCG caused dose-dependent downregulation of epidermal growth factor receptor phoshoporylation and EGFR mRNA expression and protein level in MCF-7Tam cells. There was also decrease in ERK1/2, phospho-ERK1/2, in vitro cell growth, MMP-2 and -9, and extracellular MMP-inducer while increase in TIMP-1 and -2 after EGCG treatment . EGC has been shown to inhibit heregulin -1-induced migration/invasion of MCF-7 human breast carcinoma cells to approximately the same extent as EGCG. It was found that EGCG inhibited this migration/invasion by suppressing the HRG-stimulated activation of EGFR-related protein B2 /ErbB3/Akt, whereas the disruption of the HRG-stimulated activation of ErbB2/ErbB3 but not Akt was involved in the inhibition of migration/invasion by EGC. It was concluded that EGC and EGCG could play important role against the promotion of metastasis of breast cancer cells .
Oolong Tea Extract May Stave Off Breast Cancer
New research finds that oolong tea can damage breast cancer cells and that people who consume large amounts of this tea have a lower risk of developing breast cancer.
Despite recent advances in screening procedures and treatment, breast cancer remains both the most common form of this disease and the second leading cause of cancer death among women.
According to estimates by the American Cancer Society, more than 250,000 women in the United States developed breast cancer in 2017, and more than 40,000 died as a result.
In this context, researchers are still in need of more effective prevention and treatment strategies. Moreover, given the side effects of chemotherapy, the need for nontoxic alternatives is also dire.
With these aims in mind, scientists have investigated the potential benefits of green tea for breast cancer and found that certain compounds have anti-cancer effects. However, few studies have examined other types of tea and their role in breast cancer prevention.
Now, a study looks at the potential benefits of oolong tea. Chunfa Huang, Ph.D., who is an associate research professor in the department of internal medicine at Saint Louis University in Missouri, led the new research.
Huang and colleagues their findings in the journal Anticancer Research.
, and triple-negative breast cancer cells.
The researchers treated these cells with different concentrations of green, oolong, black, and dark tea extracts.
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How Much It Costs
You can find green tea in health food shops, supermarkets, chemists and over the internet. Prices can vary depending on the amount you buy and where you buy it.
The quality or grade of green tea can also vary. Usually, better quality green tea costs more. The best quality tea is made from the first leaf buds that come in the spring.
Are There Safety Considerations Regarding Tea Consumption
Tea as a food item is generally recognized as safe by the U.S. Food and Drug Administration. Safety studies have looked at the consumption of up to 1200 mg of EGCG in supplement form in healthy adults over 1- to 4-week time periods . The adverse effects reported in these studies included excess intestinal gas, nausea, heartburn, stomach ache, abdominal pain, dizziness, headache, and muscle pain . In a Japanese study, children aged 6 to 16 years consumed a green tea beverage containing 576 mg catechins or 75 mg catechins for 24 weeks with no adverse effects . The safety of higher doses of catechins in children is not known.
Aluminum, a neurotoxic element, is found in varying quantities in tea plants. Studies have found concentrations of aluminum in infusions of green and black teas that range from 14 to 27 micrograms per liter to 431 to 2239 g/L . The variations in aluminum content may be due to different soil conditions, different harvesting periods, and water quality . Aluminum can accumulate in the body and cause osteomalacia and neurodegenerative disorders, especially in individuals with renal failure . However, it is not clear how much of the aluminum in tea is bioavailable, and there is no evidence of any aluminum toxicity associated with drinking tea .
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Mechanisms Of Action Of Green Tea Components In Breast Cancer
To better understand the preventive and therapeutic activities of green tea components on breast cancer found in animal studies, substantial research has been conducted to uncover the mechanisms at cellular and molecular levels. Experimental studies collectively show that green tea components lead to wide range of responses in animal models or breast cancer cells.
Green Tea And Reduction Of Breast Cancer Risk
| The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
| First Posted : June 10, 2009Results First Posted : February 22, 2016Last Update Posted : February 22, 2016 |
RATIONALE: Green tea extract contains ingredients 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 binding protein 3 , estrone, estradiol, androstenedione, sex hormone binding globulin , urinary estrogen metabolites and plasma F2-isoprostanes.
| Drug: Green tea extract supplementOther: Placebo | Phase 2 |
OBJECTIVES:
Primary:
1.1 To determine the effects of green tea extract consumption for 12 months on the following recognized biomarkers of breast cancer risk:
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Urinary Tea Catechin Measurement
Urine samples from participants were identified by unique codes and were assayed in a single batch. Urinary concentrations of various green tea catechins and metabolites including epigallocatechin , and 4-O-methyl-epigallocatechin were determined in the laboratory of Dr. Yang analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry with data-dependent acquisition . Urinary creatinine level was determined on each sample using standard methods.
Use For Breast Cancer Prevention
Many studies have looked at the role of green tea and breast cancer prevention. Not all of them have found an association between drinking green tea and lower breast cancer risk, but some of the largest, most credible studies have.
In the Prostate, Lung, Colorectal, and Ovarian Screening Trial, which included more than 100,000 people, researchers found that those who consumed green tea had a lower overall risk of cancer in other words, it appeared to reduce the risk of any cancer. Whereas some studies have looked at very large amounts of green teasay, drinking 30 cups dailythis study looked at people who drank just one daily cup of green tea.
A 2017 study looked at breast density in women given a supplement of EGCG for one year. High breast density is linked with an elevated risk of breast cancer. While the supplement didn’t change breast density in older women, it significantly decreased it in young women. The effect was similar to that of tamoxifen, a drug that’s sometimes used to reduce the risk of breast cancer in high-risk individuals.
The researchers concluded that further studies should be done on the role of green tea in reducing breast cancer risk in young women.
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Inhibition Of Cell Signaling Pathways
VEGF is the most significant regulator in the development of the vascular system and is commonly overexpressed in breast cancer. Green tea catechins, especially EGCG, inhibit tumor growth, proliferation, migration, and angiogenesis of breast cancer. Overexpression of Her-2/neu, the second member of epidermal growth factor receptor family, has been seen in about 30% of breast cancers and was associated with poor overall survival. EGCG treatment reduces basal phosphorylation and constitutive activation of the Her-2/neureceptor. Other investigators have demonstrated that EGCG blocks Wnt signaling through the HBP1 transcriptional repressor that was previously shown to inhibit Wnt signaling. In addition, Bigelow and Cardelli have investigated the effect of EGCG on inhibition of the hepatocyte growth factor signaling pathway. The results showed that EGCG could completely blocked phosphorylation of Met and its downstream extracellular signal-regulated kinases 1 and 2 , and Akt/protein kinase B .
Strengths And Limitations Of The Study
Some limitations have to be taken into account when reading this meta-analysis. First, the majority of the studies were conducted in Asia, mostly China and Japan, which represent the largest green tea production and consumption areas. Only one study was conducted in the USA, and no studies were conducted in Europe. This highlights the importance of performing similar studies in other ethnic populations in order to underline any potential differences. This is particularly true in determining whether other antioxidants consumed in the diet can play a confounding role. Another limitation is that self-reported green tea intake by FFQ was measured at baseline only, and the duration of tea consumption is not known. This can result in errors during both reporting and classification. Moreover, the different amounts of green tea consumed as higher intake in the original studies could have been defined in post hoc analysis.
This is likely the first meta-analysis also assessing green tea intake, the risk of BC in post-menopausal women, and BC stage. Another significant strength of the present study is that the risk for BC and recurrence were considered both together and separately. However, due to the absence of information in the original studies, it was not possible to evaluate the effect of green tea based on BC stage at diagnosis.
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