Observational studyClinical and translational science2020
The Influences of Adherence to Tamoxifen and CYP2D6 Pharmacogenetics on Plasma Concentrations of the Active Metabolite (Z)-Endoxifen in Breast Cancer.
Observational study in Clinical and translational science, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
11 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- Preliminary results using a kit to measure tamoxifen and metabolites concentrations in capillary blood samples from women with breast cancer.Scientific reports · 2022Trial
- Comprehensive CYP2D6 genotyping improves phenotype classification and highlights methodological pitfalls in tamoxifen-treated breast cancer.BMC cancer · 2026Article
- Adherence to oral anticancer medications in metastatic versus nonmetastatic breast cancer patients: Insights from a low-middle-income country.Exploratory research in clinical and social pharmacy · 2025Article
- (Z)-Endoxifen and Early Recurrence of Breast Cancer: An Explorative Analysis in a Prospective Brazilian Study.Journal of personalized medicine · 2022Article
- Article
- Generating a Precision Endoxifen Prediction Algorithm to Advance Personalized Tamoxifen Treatment in Patients with Breast Cancer.Journal of personalized medicine · 2021Review
- ClinicalCancers · 2021Review
- Simulation-Based Assessment of the Impact of Non-Adherence on Endoxifen Target Attainment in Different Tamoxifen Dosing Strategies.Pharmaceuticals (Basel, Switzerland) · 2021Article
- Endocrine Therapy in Early Breast Cancer.Breast care (Basel, Switzerland) · 2020Review
- Pharmacogenomics of breast cancer: highlighting CYP2D6 and tamoxifen.Journal of cancer research and clinical oncology · 2020Review
Corrections and comments
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Authors and funding
14 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Tamoxifen efficacy in breast cancer is suspected to depend on adherence and intact drug metabolism. We evaluated the role of adherence behavior and pharmacogenetics on the formation rate of (Z)-endoxifen. In 192 Brazilian patients, we assessed plasma levels of tamoxifen and its metabolites at 3, 6, and 12 months of treatment (liquid-chromatography tandem mass spectrometry), adherence behavior (Morisky, Green, and Levine medication adherence scale), and cytochrome P450 2D6 (CYP2D6) and other pharmacogene polymorphisms (matrix-assisted laser-desorption-ionization time of flight) mass spectrometry, real-time polymerase chain reaction). Adherence explained 47% of the variability of tamoxifen plasma concentrations (P < 0.001). Although CYP2D6 alone explained 26.4%, the combination with adherence explained 40% of (Z)-endoxifen variability at 12 months (P < 0.001). The influence of low adherence to not achieving relevant (Z)-endoxifen levels was highest in patients with noncompromised CYP2D6 function (relative risk 3.65; 95% confidence interval 1.48-8.99). As a proof-of-concept, we demonstrated that (Z)-endoxifen levels are influenced both by patient adherence to tamoxifen and CYP2D6, which is particularly relevant for patients with full CYP2D6 function.
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