Braal C Louwrens, Hussaarts Koen G A M, Seuren Lieke, Oomen-de Hoop Esther, de Bruijn Peter, Buck Stefan A J, Bos Monique E M M, Thijs-Visser Martine F, Zuetenhorst Hanneke J M, Mathijssen-van Stein Daniëlle, Vastbinder Mijntje B, van Leeuwen Roelof W F, van Gelder Teun, Koolen Stijn L W, Jager Agnes, Mathijssen Ron H J
Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, CN, PO Box 2040, 3015, Rotterdam, The Netherlands.
Department of Medical Oncology, Ikazia Hospital, Rotterdam, The Netherlands.
Breast Cancer Res Treat. 2020 Nov;184(1):107-113. doi: 10.1007/s10549-020-05829-6. Epub 2020 Aug 16.
Many cancer patients use additional herbs or supplements in combination with their anti-cancer therapy. Green tea-active ingredient epigallocatechin-3-gallate (EGCG)-is one of the most commonly used dietary supplements among breast cancer patients. EGCG may alter the metabolism of tamoxifen. Therefore, the aim of this study was to investigate the influence of green tea supplements on the pharmacokinetics of endoxifen; the most relevant active metabolite of tamoxifen.
In this single-center, randomized cross-over trial, effects of green tea capsules on endoxifen levels were evaluated. Patients treated with tamoxifen for at least 3 months were eligible for this study. After inclusion, patients were consecutively treated with tamoxifen monotherapy for 28 days and in combination with green tea supplements (1 g twice daily; containing 300 mg EGCG) for 14 days (or vice versa). Blood samples were collected on the last day of monotherapy or combination therapy. Area under the curve (AUC), maximum concentration (C) and minimum concentration (C) were obtained from individual plasma concentration-time curves.
No difference was found in geometric mean endoxifen AUC in the period with green tea versus tamoxifen monotherapy (- 0.4%; 95% CI - 8.6 to 8.5%; p = 0.92). Furthermore, no differences in C (- 2.8%; - 10.6 to 5.6%; p = 0.47) nor C (1.2%; - 7.3 to 10.5%; p = 0.77) were found. Moreover, no severe toxicity was reported during the whole study period.
This study demonstrated the absence of a pharmacokinetic interaction between green tea supplements and tamoxifen. Therefore, the use of green tea by patients with tamoxifen does not have to be discouraged.
许多癌症患者在接受抗癌治疗的同时会使用其他草药或补充剂。绿茶的活性成分表没食子儿茶素-3-没食子酸酯（EGCG）是乳腺癌患者最常用的膳食补充剂之一。EGCG可能会改变他莫昔芬的代谢。因此，本研究的目的是调查绿茶补充剂对内昔芬药代动力学的影响；内昔芬是他莫昔芬最相关的活性代谢产物。
在这项单中心、随机交叉试验中，评估了绿茶胶囊对内昔芬水平的影响。接受他莫昔芬治疗至少3个月的患者符合本研究条件。纳入后，患者连续接受他莫昔芬单药治疗28天，并与绿茶补充剂（每日两次，每次1g；含300mg EGCG）联合治疗14天（或反之）。在单药治疗或联合治疗的最后一天采集血样。从个体血浆浓度-时间曲线中获得曲线下面积（AUC）、最大浓度（C）和最小浓度（C）。
在使用绿茶与他莫昔芬单药治疗期间，内昔芬AUC的几何平均值无差异（-0.4%；95%CI -8.6至8.5%；p = 0.92）。此外，C（-2.8%；-10.6至5.6%；p = 0.47）和C（1.2%；-7.3至10.5%；p = 0.77）也无差异。此外，在整个研究期间未报告严重毒性。
本研究表明绿茶补充剂与他莫昔芬之间不存在药代动力学相互作用。因此，不必劝阻服用他莫昔芬的患者饮用绿茶。
