Predictors of treatment response in lymphogenic metastasized papillary thyroid cancer: a histopathological study.

BACKGROUND: Lymph node metastases in papillary thyroid cancer (PTC) increase the risk for persistent and recurrent disease. Data on the predictive value of histopathological features of lymph node metastases, however, are inconsistent. The aim of this study was to evaluate the prognostic significance of known and new histopathological features of lymph node metastases in a well-defined cohort of PTC patients with clinically evident lymph node metastases. METHODS: A total of 1042 lymph node metastases, derived from 129 PTC patients, were re-examined according to a predefined protocol and evaluated for diameter, extranodal extension, cystic changes, necrosis, calcifications and the proportion of the lymph node taken up by tumor cells. Predictors for a failure to achieve a complete biochemical and structural response to treatment were determined. RESULTS: The presence of more than 5 lymph node metastases was the only independent predictor for a failure to achieve a complete response to treatment (OR 3.39 [95% CI 1.57-7.33], p < 0.05). Diameter nor any of the other evaluated lymph node features were significantly associated with the response to treatment. CONCLUSIONS: Detailed re-examination of lymph nodes revealed that only the presence of more than 5 lymph node metastases was an independent predictor of failure to achieve a complete response to treatment. No predictive value was found for other histopathological features, including the diameter of the lymph node metastases. These findings have the potential to improve risk stratification in patients with PTC and clinically evident lymph node metastases.

Management of Postthyroidectomy Hypoparathyroidism and Its Effect on Hypocalcemia-Related Complications: A Meta-Analysis.

OBJECTIVE: The aim of this Meta-analysis is to evaluate the impact of different treatment strategies for early postoperative hypoparathyroidism on hypocalcemia-related complications and long-term hypoparathyroidism. DATA SOURCES: Embase.com, MEDLINE, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and the top 100 references of Google Scholar were searched to September 20, 2022. REVIEW METHODS: Articles reporting on adult patients who underwent total thyroidectomy which specified a treatment strategy for postthyroidectomy hypoparathyroidism were included. Random effect models were applied to obtain pooled proportions and 95% confidence intervals. Primary outcome was the occurrence of major hypocalcemia-related complications. Secondary outcome was long-term hypoparathyroidism. RESULTS: Sixty-six studies comprising 67 treatment protocols and 51,096 patients were included in this Meta-analysis. In 8 protocols (3806 patients), routine calcium and/or active vitamin D medication was given to all patients directly after thyroidectomy. In 49 protocols (44,012 patients), calcium and/or active vitamin D medication was only given to patients with biochemically proven postthyroidectomy hypoparathyroidism. In 10 protocols (3278 patients), calcium and/or active vitamin D supplementation was only initiated in case of clinical symptoms of hypocalcemia. No patient had a major complication due to postoperative hypocalcemia. The pooled proportion of long-term hypoparathyroidism was 2.4% (95% confidence interval, 1.9-3.0). There was no significant difference in the incidence of long-term hypoparathyroidism between the 3 supplementation groups. CONCLUSIONS: All treatment strategies for postoperative hypocalcemia prevent major complications of hypocalcemia. The early postoperative treatment protocol for postthyroidectomy hypoparathyroidism does not seem to influence recovery of parathyroid function in the long term.

Regional Collaboration and Trends in Clinical Management of Thyroid Cancer.

OBJECTIVE: This study examines the trends in the management of thyroid cancer and clinical outcomes in the Southwestern region of The Netherlands from 2010 to 2021, where a regional collaborative network has been implemented in January 2016. STUDY DESIGN: Retrospective cohort study. SETTING: This study encompasses all patients diagnosed with thyroid cancer of any subtype between January 2010 and June 2021 in 10 collaborating hospitals in the Southwestern region of The Netherlands. METHODS: The primary outcome of this study was the occurrence of postoperative complications. Secondary outcomes were trends in surgical management, centralization, and waiting times of patients with thyroid cancer. RESULTS: This study included 1186 patients with thyroid cancer. Median follow-up was 58 [interquartile range: 24-95] months. Surgery was performed in 1027 (86.6%) patients. No differences in postoperative complications, such as long-term hypoparathyroidism, permanent recurrent nerve paresis, or reoperation due to bleeding were seen over time. The percentage of patients with low-risk papillary thyroid carcinoma referred to the academic hospital decreased from 85% (n = 120/142) in 2010 to 2013 to 70% (n = 120/171) in 2014 to 2017 and 62% (n = 100/162) in 2018 to 2021 (P < .01). The percentage of patients undergoing a hemithyroidectomy alone was 9% (n = 28/323) in 2010 to 2013 and increased to 20% (n = 63/317; P < .01) in 2018 to 2021. CONCLUSION: The establishment of a regional oncological network coincided with a de-escalation of thyroid cancer treatment and centralization of complex patients and interventions. However, no differences in postoperative complications over time were observed. Determining the impact of regional oncological networks on quality of care is challenging in the absence of uniform quality indicators.

A symptom-based algorithm for calcium management after thyroid surgery: a prospective multicenter study.

Objective: Evidence-based treatment guidelines for the management of postthyroidectomy hypocalcemia are absent. The aim of this study was to evaluate a newly developed symptom-based treatment algorithm including a protocolized attempt to phase out supplementation. Methods: In a prospective multicenter study, patients were treated according to the new algorithm and compared to a historical cohort of patients treated with a biochemically based approach. The primary outcome was the proportion of patients receiving calcium and/or alfacalcidol supplementation. Secondary outcomes were calcium-related complications and predictors for supplementation. Results: One hundred thirty-four patients were included prospectively, and compared to 392 historical patients. The new algorithm significantly reduced the proportion of patients treated with calcium and/or alfacalcidol during the first postoperative year (odds ratio (OR): 0.36 (95% CI: 0.23-0.54), P < 0.001), and persistently at 12 months follow-up (OR: 0.51 (95% CI: 0.28-0.90), P < 0.05). No severe calcium-related complications occurred, even though calcium-related visits to the emergency department and readmissions increased (OR: 11.5 (95% CI: 4.51-29.3), P <0.001) and (OR: 3.46 (95% CI: 1.58-7.57), P < 0.05), respectively. The proportional change in pre- to postoperative parathyroid hormone (PTH) was an independent predictor for supplementation (OR: 1.04 (95% CI: 1.02-1.07), P < 0.05). Conclusions: Symptom-based management of postthyroidectomy hypocalcemia and a protocolized attempt to phase out supplementation safely reduced the proportion of patients receiving supplementation, although the number of calcium-related hospital visits increased. For the future, we envision a more individualized treatment approach for patients at risk for delayed symptomatic hypocalcemia, including the proportional change in pre- to post- operative PTH.

Preferences of patients, clinicians, and healthy controls for the management of a Bethesda III thyroid nodule.

BACKGROUND: Active surveillance is propagated as an alternative for hemithyroidectomy in the management of Bethesda III thyroid nodules. METHODS: A cross-sectional survey questioned respondents on their willingness to accept risks related to active surveillance and hemithyroidectomy. RESULTS: In case of active surveillance, respondents (129 patients, 46 clinicians, and 66 healthy controls) were willing to accept a risk of 10%-15% for thyroid cancer and 15% for needing more extensive surgery in the future. Respondents were willing to accept a risk of 22.5%-30% for hypothyroidism after hemithyroidectomy. Patients and controls were willing to accept a higher risk on permanent voice changes compared with clinicians (10% vs. 3%, p < 0.001). CONCLUSION: Real-life risks associated which active surveillance and hemithyroidectomy for Bethesda III nodules are equivalent or less than the risks people are willing to accept. Clinicians accepted less risk for permanent voice changes.

Establishing a Multicenter Network for Patients With Thyroid Nodules and Cancer: Effects on Referral Patterns.

OBJECTIVE: To perform a qualitative evaluation of the Thyroid Network, with a quantitative analysis of second opinion referrals for patients in the southwestern part of the Netherlands who have thyroid nodules and cancer. METHODS: This prospective observational study registered all patients with thyroid nodules and cancer who were referred to the academic hospital from 2 years before and 4 years after the foundation of the Thyroid Network. We implemented biweekly regional multidisciplinary tumor boards using video conference and a regional patient care pathway for patients with thyroid nodules and cancer. For qualitative evaluation, interviews were conducted with a broad selection of stakeholders via maximum variation sampling. The primary outcome was the change in second opinions after the foundation of the Thyroid Network. RESULTS: Second opinions from Thyroid Network hospitals to the academic hospital decreased from 10 (30%) to 2 (7%) two years after the start of the Thyroid Network (P = .001), while patient referrals remained stable (n = 108 to 106). Qualitative evaluation indicated that the uniform care pathway and the regional multidisciplinary tumor board were valued high. DISCUSSION: Establishing a regional network, including multidisciplinary tumor boards and a care pathway for patients with thyroid nodules and cancer, resulted in a decrease in second opinions of in-network hospitals and high satisfaction of participating specialists. IMPLICATIONS FOR PRACTICE: The concept of the Thyroid Network could spread to other regions as well as to other specialties in health care. Future steps would be to assess the effect of regional collaboration on quality of care and patient satisfaction.

Persistent post-thyroidectomy hypoparathyroidism: A multicenter retrospective cohort study.

BACKGROUND AND OBJECTIVE: The reported incidence of persistent hypoparathyroidism varies widely, and consensus on a definition is lacking. The objective was to evaluate the real-life incidence of persistent hypoparathyroidism by investigating a new pragmatic definition. METHODS: This retrospective multicenter cohort study evaluated the effect of different definitions for persistent hypoparathyroidism on the incidence of hypoparathyroidism. In addition, risk factors for hypoparathyroidism were analyzed. RESULTS: In total, 749 patients were included. Using the new pragmatic definition, we report an incidence of 7.9% of persistent hypoparathyroidism. When applying other commonly used definitions, incidence varied between 11.8% and 22.1%. Risk factors were parathyroid autotransplantation, presence of another surgical complication, and low postoperative serum calcium. CONCLUSIONS: Our data show that the incidence of persistent hypoparathyroidism in the literature may vary through the use of different definitions. This study indicates that a new pragmatic definition of persistent hypoparathyroidism has the potential to enable unbiased comparison between studies.

Thyroglobulin and thyroglobulin antibodies: assay-dependent management consequences in patients with differentiated thyroid carcinoma.

OBJECTIVES: International guidelines recommend fixed cut-off values for thyroglobulin (Tg). These cut-offs do not take potential assay differences into account. This study aimed to evaluate if different assays for Tg and Tg antibodies (TgAb) affect management guidance for differentiated thyroid cancer (DTC) patients. METHODS: In 793 samples derived from 413 patients with DTC, Tg and TgAb were simultaneously measured with two immunometric assays: Immulite 2000XPi and Kryptor compact plus. In addition, a qualitative measurement for TgAb interference (recovery test) was performed on the Kryptor compact plus platform. The extent to which different assays lead to different classifications of response to therapy was evaluated when applying the current cut-offs for Tg. RESULTS: Mean Tg concentrations were 37.4% lower with Kryptor as compared with Immulite. Applying guideline based cut-off values for Tg, 33 (4.7%) samples had a Tg-on concentration ≥1.0 µg/L with Immulite and <1.0 µg/L with Kryptor. Of the samples tested as TgAb+ with at least one assay (n=125), 68 (54.4%) samples showed discrepancy in TgAb status. Differences between Immulite and Kryptor measurements resulted in a change in the response to therapy classification in 94 (12.0%) measurements derived from 67 (16.2%) individual patients. CONCLUSIONS: A substantial portion of DTC patients were classified differently dependent on which Tg and TgAb assays are used, when applying the cut-off values as defined in clinical guidelines. Such differences can significantly affect clinical management. In the context of large between-method variation, the recommended Tg cut-offs in guidelines should be used with wisdom rather than as fixed cut-offs.

Impact of Thyroglobulin and Thyroglobulin Antibody Assay Performance on the Differential Classification of DTC Patients.

CONTEXT: Measurements of thyroglobulin (Tg) and Tg antibodies are crucial in the follow-up of treated differentiated thyroid cancer (DTC) patients. Interassay differences may significantly impact follow-up. OBJECTIVE: The aim of this multicenter study was to explore the impact of Tg and Tg antibody assay performance on the differential classification of DTC patients, as described in national and international guidelines. DESIGN: Four commonly used Tg and Tg antibody assays were technically compared to reflect possible effects on patients with DTC follow-up. Storage stability at different storage temperatures was also investigated for LIAISON® and Kryptor assays, as this is an underexposed topic in current literature. RESULTS: B.R.A.H.M.S. assays yield approximately 50% lower Tg values over the whole range compared to the DiaSorin and Roche assays investigated. These differences between assays may result in potential misclassification in up to 7% of patients if fixed cutoffs (eg, 1 ng/mL) are applied. Poor correlation was also observed between the Tg antibody assays when the method-specific upper limits of normal are used as cutoffs. Storage of Tg and Tg antibodies was possible for 3 to 4 weeks at -20°C and -80°C. Calibration of the assays, however, was found to be crucial for stable results over time. CONCLUSIONS: Technical aspects of Tg and Tg antibody assays, including interassay differences, calibration and standardization, and cutoff values, may have a significant clinical impact on the follow-up of DTC patients.

High-flow Nasal Cannula therapy: A feasible treatment for vulnerable elderly COVID-19 patients in the wards.

BACKGROUND: Invasive mechanical ventilation is the treatment of choice in COVID-19 patients when hypoxemia persists, despite maximum conventional oxygen administration. Some frail patients with severe hypoxemic respiratory failure are deemed not eligible for invasive mechanical ventilation. OBJECTIVES: To investigate whether High-flow nasal cannula (HFNC) in the wards could serve as a rescue therapy in these frail patients. METHODS: This retrospective cohort study included frail COVID-19 patients admitted to the hospital between March 9th and May 1st 2020. HFNC therapy was started in the wards. The primary endpoint was the survival rate at hospital discharge. RESULTS: Thirty-two patients with a median age of 79.0 years (74.5-83.0) and a Clinical Frailty Score of 4 out of 9 (3-6) were included. Only 6% reported HFNC tolerability issues. The overall survival rate was 25% at hospital discharge. CONCLUSIONS: This study suggests that, when preferred, HFNC in the wards could be a potential rescue therapy for respiratory failure in vulnerable COVID-19 patients.

Preferences of patients and clinicians for treatment of Graves' disease: a discrete choice experiment.

OBJECTIVE: Treatment options for Graves' disease (GD) consist of antithyroid drugs (ATD), radioactive iodine (RAI) and total thyroidectomy (TT). Guidelines recommend to discuss these options with patients, taking into account patients' preferences. This study aims to evaluate and compare patients' and clinicians' preferences and the trade-offs made in choosing treatment. DESIGN AND METHODS: A discrete choice experiment (DCE) was performed with GD patients with a first diagnosis or recurrence in the previous year, and with clinicians. Participants were offered hypothetical treatment options which differed in type of treatment, rates of remission, severe side effects, permanent voice changes and hypocalcemia. Preference heterogeneity was assessed by latent-class analysis. RESULTS: In this study, 286 (82%) patients and 61 (18%) clinicians participated in the DCE. All treatment characteristics had a significant effect on treatment choice (P < 0.05). Remission rate was the most important determinant and explained 37 and 35% of choices in patients and clinicians, respectively. Both patients and clinicians preferred ATD over surgery and RAI. A strong negative preference toward RAI treatment was observed in a subclass of patients, whereas clinicians preferred RAI over surgery. CONCLUSION: For both patients and clinicians, remission rate was the most important determinant of treatment choice and ATD was the most preferred treatment option. Patients had a negative preference toward RAI compared to alternatives, whereas clinicians preferred RAI over surgery. Clinicians should be aware that their personal attitude toward RAI differs from that of their patients. This study on patients' and clinicians' preferences can support shared decision making and thereby improve clinical treatment.

Clinical Guidelines and PTH Measurement: Does Assay Generation Matter?

PTH is an important regulator of calcium and phosphate homeostasis and bone remodeling. It is metabolized into PTH fragments, which are measured to a different extent by PTH assays of different generations because of differences in fragments recognized and lack of assay standardization. PTH is measured in the workup of several conditions, and clinical guidelines provide recommendations concerning these measurements. This review provides an overview of the impact of differences between PTH assays, applying distinct clinical guidelines for primary and secondary hyperparathyroidism and perioperative use of PTH measurements. Guidelines deal with PTH measurement in different ways, recommending either trend monitoring, the use of a fold increase of the upper reference limit, or an absolute PTH cutoff value. For classic primary hyperparathyroidism (PHPT), the type of PTH assay used will not affect diagnosis or management because the precise concentration of PTH is less relevant. In chronic kidney disease, the guideline recommends treating secondary hyperparathyroidism above a twofold to ninefold PTH increase, which will result in different clinical decisions depending on the assay used. For patients after bariatric surgery, guidelines state absolute cutoff values for PTH, but the impact of different generation assays is unknown because direct comparison of PTH assays has never been performed. During parathyroid surgery, PTH measurements with a third-generation assay reflect treatment success more rapidly than second-generation assays. Increased awareness among clinicians regarding the complexity of PTH measurements is warranted because it can affect clinical decisions.

Sudden cardiac death is associated both with epilepsy and with use of antiepileptic medications.

OBJECTIVE: Epilepsy is associated with increased risk for sudden cardiac death (SCD). We aimed to establish, in a community based study, whether this association is mediated by epilepsy per se, use of antiepileptic medications (AEMs), or both. METHODS: We studied SCD cases and age/sex matched controls in a case-control study in a large scale general practitioners' research database (n=478 661 patients). SCD risk for symptomatic epilepsy (seizure <2 years before SCD), stable epilepsy (no seizure <2 years before SCD), and use of AEMs (any indication) was determined. RESULTS: We identified 926 SCD cases and 9832 controls. Fourteen cases had epilepsy. Epilepsy was associated with an increased SCD risk (cases 1.5%, controls 0.5%; adjusted OR 2.8, 95% CI 1.4 to 5.3). SCD risk was increased for symptomatic epilepsy (cases 0.9%, controls 0.1%; adjusted OR 5.8, 95% CI 2.1 to 15.6), but not with stable epilepsy (cases 0.6%, controls 0.4%; adjusted OR 1.6, 95% CI 0.7 to 4.1). AEM use was found in 23 cases and was associated with an increased SCD risk (cases 2.5%, controls 0.8%; adjusted OR overall 2.6, 95% CI 1.5 to 4.3) among symptomatic epilepsy cases (cases 0.9%, controls 0.1%; adjusted OR 6.4, 95% CI 2.4 to 17.4) and non-epilepsy cases (cases 1.0%, controls 0.4%; adjusted OR 2.3, 95% CI 1.01 to 5.2). Increased SCD risk was associated with sodium channel blocking AEMs (cases 1.6%, controls 0.4%; adjusted OR 2.8, 95% CI 1.1 to 7.2), but not with non-sodium channel blocking AEMs. Carbamazepine and gabapentin were associated with increased SCD risk (carbamazepine: cases 1.1%, controls 0.3%; adjusted OR 3.2, 95% CI 1.1 to 9.2; gabapentin: cases 0.3%, controls 0.1%; adjusted OR 5.7, 95% CI 1.2 to 27.9). CONCLUSIONS: Epilepsy and AEM use are both associated with increased SCD risk in the general population. Poor seizure control contributes to increased SCD risk in epilepsy, while sodium channel blockade contributes to SCD susceptibility in AEM users.

Not-in-trial simulation I: Bridging cardiovascular risk from clinical trials to real-life conditions.

AIMS: The assessment of heart rate-corrected QT (QTc) interval prolongation relies on the evidence of drug effects in healthy subjects. This study demonstrates the relevance of pharmacokinetic-pharmacodynamic (PKPD) relationships to characterize drug-induced QTc interval prolongation and explore the discrepancies between clinical trials and real-life conditions. METHODS: d,l-Sotalol data from healthy subjects and from the Rotterdam Study cohort were used to assess treatment response in a phase I setting and in a real-life conditions, respectively. Using modelling and simulation, drug effects at therapeutic doses were predicted in both populations. RESULTS: Inclusion criteria were shown to restrict the representativeness of the trial population in comparison to real-life conditions. A significant part of the typical patient population was excluded from trials due to weight and baseline QTc interval criteria. Relative risk was significantly different between sotalol users with and without heart failure, hypertension, diabetes and myocardial infarction (P < 0.01). Although drug effects do cause an increase in the relative risk of QTc interval prolongation, the presence of diabetes represented an increase from 4.0 [95% confidence interval (CI) 2.7-5.8] to 6.5 (95% CI 1.6-27.1), whilst for myocardial infarction it increased from 3.4 (95% CI 2.3-5.13) to 15.5 (95% CI 4.9-49.3). CONCLUSIONS: Our findings show that drug effects on QTc interval do not explain the observed QTc values in the population. The prevalence of high QTc values in the real-life population can be assigned to co-morbidities and concomitant medications. These findings substantiate the need to account for these factors when evaluating the cardiovascular risk of medicinal products.

[Ethnic differences in laboratory results]. / Etnische verschillen in referentiewaarden.

Over the years the Netherlands has become a country with a population comprising over 20% of immigrants. Immigrants differ from natives in both biological and cultural aspects, amongst others in laboratory results, but also in level of participation in clinical trials, and treatment outcomes. It is important for physicians to keep these differences between ethnic groups in mind. The authors argue that specific reference ranges for subgroups should be established.

Invited commentary: sex-steroid hormones and QT-interval duration.

In this issue of the Journal, Zhang et al. (Am J Epidemiol. 2011;174(4):403-411) make a substantial contribution to research in the area of hormonal influences on cardiac repolarization by demonstrating an inverse association between testosterone levels and the Bazett's adjusted QT interval (QTc) and RR-adjusted QT interval in men but not in postmenopausal women. They suggest that testosterone levels might explain the difference in QTc-interval duration between men and women and could contribute to population variability in QTc-interval duration among men. In this commentary, the gender difference and the role of testosterone in human cardiac repolarization are addressed. In addition, the gender differences in the congenital long-QT syndrome, drug-induced ventricular arrhythmias, and sudden cardiac death are discussed.

Proton pump inhibitors and the risk of overanticoagulation during acenocoumarol maintenance treatment.

In the Netherlands, several reports have described a potentiation of acenocoumarol-induced anticoagulation by co-medication of omeprazole or esomeprazole and competitive inhibition of CYP2C19 has been suggested as a possible mechanism for this interaction. We conducted an observational cohort study to investigate the effects of various proton pump inhibitors (PPIs) on acenocoumarol effectiveness. All 2755 subjects from the Rotterdam Study who received acenocoumarol maintenance treatment between April 1st, 1991 and September 9th, 2009 were followed for events of an international normalized ratio (INR)≥6, until death, end of treatment, or end of the study period. The Andersen-Gill extension of the Cox proportional hazards model was used to calculate risks for repeated events of overanticoagulation in relation to concomitant PPI use. The risk for overanticoagulation was most pronounced for esomeprazole (HR 1·99, 95% CI 1·55-2·55) and lansoprazole (HR 1·49, 95% CI 1·05-2·10). There was also a lower and non-significant risk increase for the other PPIs. We did not detect a modification of these results by CYP2C19*2 genotype. Caution should be paid to co-medication with esomeprazole and lansoprazole during acenocoumarol treatment and possibly also with other PPIs.

Non-cardiovascular drugs that inhibit hERG-encoded potassium channels and risk of sudden cardiac death.

BACKGROUND: Virtually all QTc-prolonging drugs act by blocking the human ether a go-go-related gene (hERG)-encoded potassium channels (hERG channels), whereas not all QTc-prolonging drugs are associated with an increased risk of serious cardiac arrhythmias. This study assessed whether non-cardiovascular hERG channel blockers are associated with an increased risk of sudden cardiac death (SCD) and whether hERG-channel-inhibiting capacity is an indicator of the risk of SCD. METHODS AND RESULTS: The risk of SCD was studied in the Integrated Primary Care Information database, a longitudinal general practice research database. A case-control study was performed, matched for age, gender and calendar time. Odds ratios were calculated with conditional logistic regression, multivariably adjusted. In addition, the hERG-channel-inhibiting capacity of the different drugs was compared, defined as the effective free therapeutic plasma concentration (ETCP(unbound)) divided by the concentration that inhibits 50% of the potassium channels (IC50), with the risk of SCD. 1424 cases of SCD and 14 443 controls were identified. Current use of hERG channel blockers was associated with an increased risk of SCD. The risk of SCD was significantly increased in users of antipsychotic drugs. Patients using hERG channel blockers with a high ETCP(unbound)/IC50 ratio (≥ 0.033) had a higher risk of SCD than patients using drugs with a low ETCP(unbound)/IC50 ratio (<0.033). CONCLUSIONS: The current use of hERG channel blockers was associated with an increased risk of SCD in the general population. In addition, drugs with a high hERG-channel-inhibiting capacity had a higher risk of SCD than drugs with a low hERG-channel-inhibiting capacity.

CYP2C19*2 polymorphism is associated with increased survival in breast cancer patients using tamoxifen.

AIMS: Variant alleles of the CYP2C19 gene were recently associated with survival in breast cancer patients on tamoxifen therapy. CYP2C19 is one of the enzymes involved in the metabolism of tamoxifen into active metabolites. We investigated the hypothesis that CYP2C19*2 and *3 variants, known for their lack of enzyme activity, are associated with an increased breast cancer mortality rate in patients using tamoxifen. MATERIALS & METHODS: In the prospective population based Rotterdam study, the association between CYP2C19*2 carriers and breast cancer mortality was studied among 80 incident users of tamoxifen. Survival was analyzed with life tables and Cox regression analysis, with drug exposure as a time-dependent variable. Adjustments were made for calendar time, average tamoxifen dose, age, the indication for tamoxifen, CYP2D6 genotype and concomitant use of CYP2C19 inhibitors or inducers. RESULTS: In patients on tamoxifen, CYP2C19*2 carriers were associated with a significantly longer breast cancer survival rate than patients with the wild-type (hazard ratio 0.26, 95%CI: 0.08-0.87). CONCLUSION: This study suggests that CYP2C19 genotype may possibly be a predictive factor for survival in breast cancer patients using tamoxifen.