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Cheng YY, Zheng T, Chang MW, Dalley JW, Chen YJ, Tsai TH, Hsieh CH. Impact of Irradiation on the Pharmacokinetics and Biotransformation of Tamoxifen. Front Oncol 2022; 12:833108. [PMID: 35252004 PMCID: PMC8891439 DOI: 10.3389/fonc.2022.833108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe optimal procedure for combining radiotherapy (RT) with tamoxifen treatment is controversial as RT may alter the pharmacokinetics and biotransformation of tamoxifen. The present study investigated this potential interaction by assessing the pharmacokinetics of tamoxifen during concurrent and sequential RT.MethodPlasma tamoxifen concentration was measured in rats with or without RT 2.0 Gy (RT2.0Gy) or 0.5 Gy (RT0.5Gy) with ultra-high-performance liquid chromatography-tandem mass spectrometry after tamoxifen administration (10 mg/kg, p.o., n = 6). Tamoxifen was either administered 1 h after RT (concurrent condition) or 24 h after RT (sequential condition).ResultsPharmacokinetic data analysis demonstrated that the area under the curve (AUC) and half-life of tamoxifen were 2,004 ± 241 h ng/ml and 6.23 ± 1.21 h, respectively, after tamoxifen administration (10 mg/kg, p.o.). The respective conversion rate of 4-hydroxytamoxifen, N-desmethytamoxifen, and endoxifen for tamoxifen metabolism was 20%, 16%, and 5%. The AUC value of tamoxifen in the RT0.5Gy group was 1.5- to 1.7-fold higher than in the sham and RT2.0Gy groups. The relative bioavailability of tamoxifen at concurrent RT0.5Gy and RT2.0Gy groups ranged from 127% to 202% and from 71% to 152%, respectively. The magnitude of endoxifen, which converted from 4-hydroxytamoxifen and N-desmethyltamoxifen, increased 3- to 5-fold in the concurrent RT groups. By contrast, the AUC of tamoxifen decreased by roughly 24% in the sequential RT2.0Gy group. The conversion ratio of endoxifen was four times higher than that in the sequential RT2.0Gy group compared with rats not exposed to RT.ConclusionThe current study provides advanced pharmacokinetic data to confirm the interaction between RT and hormone therapy. Our findings indicate that RT facilitates the metabolism of tamoxifen to active metabolites and thus imply that combination RT-tamoxifen has potential benefits for the treatment of hormone-dependent breast cancer.
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Affiliation(s)
- Yung-Yi Cheng
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, the University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Institute of Traditional Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Teresa Zheng
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, the University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Michael W. Chang
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, the University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jeffrey W. Dalley
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Yu-Jen Chen
- Department of Radiation Oncology, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Artificial Intelligence and Medical Application, MacKay Junior College of Medicine, Nursing and Management, Taipei, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City, Taiwan
- *Correspondence: Yu-Jen Chen, ; Tung-Hu Tsai, ; Chen-Hsi Hsieh, ;
| | - Tung-Hu Tsai
- Institute of Traditional Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Yu-Jen Chen, ; Tung-Hu Tsai, ; Chen-Hsi Hsieh, ;
| | - Chen-Hsi Hsieh
- Institute of Traditional Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- *Correspondence: Yu-Jen Chen, ; Tung-Hu Tsai, ; Chen-Hsi Hsieh, ;
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