Eliciting Low-Risk Thyroid Cancer Treatment Preferences Using Clinical Vignettes: A Pilot Study.

OBJECTIVE: While surgical resection has been the traditional standard treatment for small (≤1 cm), differentiated thyroid cancers, active surveillance (AS) and radiofrequency ablation (RFA) are increasingly considered. The aim of this study was to explore patient preferences in thyroid cancer treatment using a series of clinical vignettes. METHODS: Thyroid cancer survivors and general population volunteers were recruited to rank experience-driven clinical vignettes in order of preference. Rankings were compared using Wilcoxon signed rank. Formative qualitative methods were used to develop and refine clinical vignettes that captured 4 treatments-thyroid lobectomy (TL), total thyroidectomy (TT), AS, and RFA-along with 6 treatment complications. Content was validated via interviews with 5 academic subspecialists. RESULTS: Nineteen volunteers participated (10 survivors, 9 general population). Treatment complications were ranked lower than uncomplicated counterparts in 99.0% of cases, indicating excellent comprehension. Counter to our hypothesis, among uncomplicated vignettes, median rankings were 1 for AS, 2 for RFA, 3.5 for TL, and 5 for TT. Trends were consistent between thyroid cancer survivors and the general population. AS was significantly preferred over RFA (P = .02) and TT (P < .01). Among surgical options, TL was significantly preferred over TT (P < .01). CONCLUSION: When treatments for low-risk thyroid cancer are described clearly and accurately through clinical vignettes, patients may be more likely to choose less invasive treatment options over traditional surgical resection.

Constructing Health State Descriptions for Low-Risk Thyroid Cancer: Stakeholder Engagement and Formative Qualitative Research.

OVERVIEW: This paper describes stakeholder involvement and formative qualitative research in the creation of health state descriptions (HSDs) or vignettes for low-risk thyroid cancer. The aim of this project was to engage stakeholders in the contribution of a novel set of HSDs, an important first step in the process of assessing value in thyroid cancer health states. METHODS: We draw upon formative, descriptive qualitative methods, following a multi-stage framework of data collection. We conducted individual semi-structured interviews, cognitive interviews, and focus groups with thyroid cancer patients, community providers, academic subspecialists, and participants with no thyroid cancer diagnosis (N = 31). The HSDs went through several iterations over the course of a year, in collaboration with a highly engaged community advisory board, laying the groundwork for HSDs that are comprehensible, comparable, and appropriate for stated-preference research. FINDINGS: Thyroid cancer survivors compared their experiences with those described in the HSDs. Feedback included concern for the emotional well-being of study participants who would be reading them. Providers were attuned to the need for clinical accuracy and made suggestions to reflect their clinical experience, including for patients with complications or disease progression. The pilot participants with no thyroid cancer were particularly valuable in promoting the need to simplify language and maximize readability. DISCUSSION: Stakeholder engagement was critical to being responsive to feedback as the iterations were refined and presented. Continuous engagement and consultation with multiple sources strengthened the HSDs. A secondary outcome from this project is that stakeholders expressed interest in adapting the HSDs into decision aids for people newly diagnosed with low-risk thyroid cancer.

Substituted imidazole of 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine Inactivates cytochrome P450 2D6 by protein adduction.

5-Fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) is a potent mechanism-based inactivator of human cytochrome P450 2D6 that displays type I binding spectra with a K(s) of 0.39 ± 0.10 µM. The partition ratio is ~3, indicating potent inactivation that addition of exogenous nucleophiles does not prevent. Within 15 min of incubation with SCH 66712 and NADPH, ∼90% of CYP2D6 activity is lost with only ~20% loss in ability to bind CO and ~25% loss of native heme over the same time. The stoichiometry of binding to the protein was 1.2:1. SDS-polyacrylamide gel electrophoresis with Western blotting and autoradiography analyses of CYP2D6 after incubations with radiolabeled SCH 66712 further support the presence of a protein adduct. Metabolites of SCH 66712 detected by mass spectrometry indicate that the phenyl group on the imidazole ring of SCH 66712 is one site of oxidation by CYP2D6 and could lead to methylene quinone formation. Three other metabolites were also observed. For understanding the metabolic pathway that leads to CYP2D6 inactivation, metabolism studies with CYP2C9 and CYP2C19 were performed because neither of these enzymes is significantly inhibited by SCH 66712. The metabolites formed by CYP2C9 and CYP2C19 are the same as those seen with CYP2D6, although in different abundance. Modeling studies with CYP2D6 revealed potential roles of various active site residues in the oxidation of SCH 66712 and inactivation of CYP2D6 and showed that the phenyl group of SCH 66712 is positioned at 2.2 Å from the heme iron.

HPLC determination of caffeine and paraxanthine in urine: An assay for cytochrome P450 1A2 activity.

Cytochrome P450 enzymes are a family of heme-containing proteins located throughout the body with roles in metabolism of endogenous and exogenous compounds. Among exogenous compounds, clinically relevant pharmaceutical agents are nearly all metabolized by P450 enzymes. However, the activity of the different cytochrome P450 enzymes varies among individuals and, therefore, so does drug efficacy as well as susceptibility to side effects and toxicity. Thus, assessing P450 activity is of great interest in drug development and clinical pharmacology. This study investigates the phenotyping of a single P450 activity by analyzing urine samples using isocratic reverse-phase HPLC. Specifically, the activity of human P450 1A2, which converts caffeine into paraxanthine, can be investigated by measuring the change in caffeine and paraxanthine concentrations in urine over time following a single dose of caffeine. There is an observable relationship between caffeine intake and paraxanthine formation that varies among individuals. This laboratory exercise provides a means for simple assessment of P450 1A2 metabolic activity using an HPLC method without additional extraction or purification steps and introduces students to the complexities of individualized medicine as well as the basic biochemical techniques of sample preparation and quantitative HPLC. Furthermore, students may design and test their own hypothesis using these methods.