Abstract
Abstract.Purpose: Teas are an essential part of traditional phytotherapy. The aim of this systematic review is to assess the clinical evidence using green tea catechins in cancer care. Methods: A systematic search was conducted searching five electronic databases concerning the effectiveness and risks of epigallocatechin gallate (EGCG) on cancer patients. Results: Seven studies with 371 patients were included. Patients were mainly suffering from breast and prostate cancer. Dosing ranged from 28 mg to 1600 mg EGCG, intervention time from 7 days to 6 months with different applications (topical 2 studies; oral 5 studies). The studies showed heterogeneous methodological quality and results leading not to conduct a meta-analysis. There was a small decrease in prostate-specific-antigen levels in one study (N=60; T0:(mean±SD) 9.6±5.2 ng/ml, T1: 8.4±4.3 ng/ml vs. T0: 9.9±8.5 ng/ml, T1: 10.0±9.0 ng/ml; p=0.04), whereas in a second study only a trend was seen. Topical green tea was as effective as metronidazole powder in reducing the odor of fungating malignant wounds (1 study; N=30) with a consequent increase in quality of life (QoL) (p<0.001), improvement of appetite (p<0.001), malodorous control (p<0.001), social activities (p<0.001). Radiotherapy-induced diarrhea was lower in the green tea intervention group compared to placebo (1 study; N=42; week 4+5: without diarrhea p=0.002). Conclusions: The studies suggest that EGCG is as effective as a local antibiotic in malodorous control and improvement of QoL of fungating malignant wounds. Green tea could be a possible complementary method for treating acute radiation-induced diarrhea. Due to limitations, further studies with higher methodological quality and larger sample sizes are needed.
References
1 . International Agency for Research on Cancer. Press Release No 263 [Internet]. 2018. Available from: https://www.who.int/cancer/PRGlobocanFinal.pdf
2 . Was ist das Ziel einer Krebsbehandlung? [Internet]. 2009. Available from: https://www.kinderkrebsinfo.de/patienten/fragen_zu_krebs/was_ist_das_ziel_einer_krebsbehandlung/index_ger.html
3 . The effect of cancer treatment on cognitive function. Clin Adv Hematol Oncol. 2015;13(7):441–50.
4 Journal of Oncology Navigation and Survivorship. Physical/Psychological Disability Common in Cancer Patients [Internet]. 2017. Available from: http://www.jons-online.com/issues/2017/october-2017-vol-8-no-10/1703-physicalpsychological-disability
5 Predictive factors for the use of complementary and alternative medicine (CAM) in radiation oncology. Eur J Integr Med. 2009;1(1):19–25.
6 User rate of complementary and alternative medicine (CAM) of patients visiting a counseling facility for CAM of a German comprehensive cancer center. Anticancer Res. 2014;34(2):943–8.
7 . How many cancer patients use complementary and alternative medicine: a systematic review and metaanalysis. Integr Cancer Ther. 2012;11(3):187–203.
8 Potential interactions of complementary and alternative medicine with cancer therapy in outpatients with gynecological cancer in a comprehensive cancer center. J Cancer Res Clin Oncol. 2013;139(3):357–65.
9 Use of complementary medicine in metastatic melanoma patients treated with ipilimumab within a clinical trial. J Dtsch Dermatol Ges. 2016;14(5):508–13.
10 Risk of interactions between complementary and alternative medicine and medication for comorbidities in patients with melanoma. Med Oncol. 2016;33(52).
11 . Naturally occurring NF-κB inhibitors. Mini Rev Med Chem. 2006;6(8):945–51.
12 The effect of complementary and alternative medicines on CYP3A4-mediated metabolism of three different substrates: 7-benzyloxy-4-trifluoromethyl-coumarin, midazolam and docetaxel. J Pharm Pharmacol. 2014;66(6):865–74.
13 . The roles of polyphenols in cancer chemoprevention. Biofactors. 2006;26(2):105–21.
14 . Anti-melanoma effects of vorinostat in combination with polyphenolic antioxidant (−)-epigallocatechin-3-gallate (EGCG). Pharm Res. 2010;27(6):1103–14.
15 . Tea catechins inhibit angiogenesis in vitro, measured by human endothelial cell growth, migration and tube formation, through inhibition of VEGF receptor binding. Cancer Lett. 2002;180(2):139–44.
16 Epigallocatechin-3-gallate inhibits secretion of TNF-α, IL-6 and IL-8 through the attenuation of ERK and NF-κB in HMC-1 cells. Int Arch Allergy Immunol. 2007;142(4):335–44.
17 McMaster University. Health Sciences Library. Guides & Tutorials. Nursing: Forming Questions [Internet]. [cited 2020 Jun 16]. Available from: https://hslmcmaster.libguides.com/nursing/questions
18 Scottish Intercollegiate Guidelines Network. Healthcare Improvement Scotland. Critical appraisal notes and checklists [Internet]. [cited 2020 Jun 16].Available from: https://www.sign.ac.uk/checklists-and-notes
19 RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366.
20 AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ. 2017;358:j4008.
21 . Oxford Centre for Evidence-based Medicine – Levels of Evidence [Internet]. 2009. Available from: https://www.cebm.net/2009/06/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/
22 . German Guideline Program in Oncology (GGPO) [Internet]. 2008. Available from: https://www.leitlinienprogramm-onkologie.de/english-language/
23 Randomized, double-blind, placebo-controlled trial of polyphenon E in prostate cancer patients before prostatectomy: evaluation of potential chemopreventive activities. Cancer Prev Res (Phila). 2012;5(2):290–8.
24 . Double-blinded, randomized, placebo-controlled study to evaluate the effectiveness of green tea in preventing acute gastrointestinal complications due to radiotherapy. J Res Med Sci. 2014;19(5):445–50.
25 Randomized clinical trial of brewed green and black tea in men with prostate cancer prior to prostatectomy. The Prostate. 2015;75(5):550–9.
26 . Green tea improves metabolic biomarkers, not weight or body composition: a pilot study in overweight breast cancer survivors. J Hum Nutr Diet. 2010;23(6):590–600.
27 Topical sinecatechins, 10%, ointment for superficial basal cell carcinoma: a randomized clinical trial. JAMA dermatology. 2017;153(10):1061–3.
28 . Comparing the effectiveness of green tea versus topical metronidazole powder in malodorous control of fungating malignant wounds in a controlled randomised study. Proc Singapore Healthc. 2014;23(1):3–12.
29 Phase IB randomized, double-blinded, placebo-controlled, dose escalation study of polyphenon E in women with hormone receptor-negative breast cancer. Cancer Prev Res (Phila). 2012;5(9):1144–54.
30 . Green tea and lung cancer: a systematic review. Integr Cancer Ther. 2013;12(1):7–24.
31 . Toxicological effects of Camellia sinensis (green tea): A review. Phytother Res. 2018;32(7):1163–80.
32 Safety of green tea extracts. Drug Saf. 2008;31(6):469–84.
33 Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid–based proteasome inhibitors. Blood. 2009;113(23):5927–37.