Falsely elevated serum oestradiol due to exemestane therapy

Estrogen levels in young women with hormone receptor-positive breast cancer on ovarian function suppression therapy

Ovarian function suppression (OFS) benefits young women with hormone receptor (HR)-positive breast cancer but they are at risk for ovarian function breakthrough. We assessed endocrine effects of gonadotropin-releasing hormone agonist (GnRHa) treatment in a prospective cohort of patients aged ≤ 40 years with HR-positive breast cancer. Plasma estradiol (E2), estrone, and follicule-stimulating hormone (FSH) levels were measured from blood samples drawn 1 and 4 years after diagnosis. Patient characteristics, invasive breast cancer-free survival (iBCFS), and overall survival (OS) were compared between those with and without E2 > 2.72 pg/mL during GnRHa treatment. Among eligible patients, 54.7% (46/84) and 60% (15/25) had E2 > 2.72 pg/mL at 1 and 4 years, respectively. Factors associated with E2 > 2.72 pg/mL at 1 year were no prior chemotherapy (P = 0.045) and tamoxifen use (P = 0.009). After a median follow-up of 7 years, among patients with stage I-III breast cancer (N = 74), iBCFS events were seen in 6 (8.1%) with E2 > 2.72 pg/mL and 5 (6.8%) with E2 ≤ 2.72 pg/mL (P = 0.893). Among patients with de novo metastatic breast cancer (N = 12), 6 (50%) with E2 > 2.72 pg/mL and 3 (25%) with E2 ≤ 2.72 pg/mL died during follow-up (P = 0.052). Larger studies exploring the clinical implications of incomplete E2 suppression by GnRHa are needed to ensure optimal OFS treatment strategies are being employed for this population.

Measuring serum oestrogen levels in breast cancer survivors using vaginal oestrogens: a systematic review

PURPOSE

Vaginal oestrogens can be used to treat genitourinary symptoms in women with early breast cancer. Studies evaluating vaginal oestrogens have commonly measured serum oestrogen levels as a surrogate marker of safety, but methods vary. We sought to summarise the data on serum oestrogen measurement in women with breast cancer using vaginal oestrogens to better understand the methods, levels and reliability.

METHODS

We searched Medline, Embase, CENTRAL, SCOPUS and CINAHL from inception to October 2023 for clinical studies where serum oestrogen was measured in women with a history of early breast cancer using vaginal oestrogens. Studies with a reported testing methodology were included.

RESULTS

Nine studies met the inclusion criteria for this systematic review. Methods used to measure oestradiol and oestriol in selected studies included mass spectrometry and immunoassays; several studies used more than one with variable concordance. Mass spectrometry detected oestradiol levels down to a lower limit between 1.0 pg/mL and 3.0 pg/mL. Immunoassays such as ELISA (enzyme-linked immunosorbent assay), ECLIA (enhanced chemiluminiscence immunoassay) and RIA (radioimmunoassay) had lower detection limits ranging between 0.8 pg/mL and 10 pg/mL. Studies were heterogeneous in testing techniques used, timing of testing, and the population including with subsequent varying results in the effect on oestrogens reported.

CONCLUSIONS

Adopting consistent and standardised methods of measuring oestrogens in clinical trials involving women with early breast cancer on vaginal oestrogens is critical. Serum oestrogens are used as a surrogate marker of safety in this population, and good-quality data are necessary to enable clinicians and patients to feel confident in prescribing and taking vaginal oestrogens. Mass spectrometry, although more expensive, gives more reliable results when dealing with very low levels of oestrogens often found in women on aromatase inhibitors, compared to immunoassays.

Pitfalls in the lab assessment of hypopituitarism

The diagnostic approach to hypopituitarism involves many disciplines. Clinical symptoms rarely are specific. Imaging techniques are helpful but cannot prove the specific functional defects. Therefore, the definitive diagnosis of pituitary insufficiency is largely based on laboratory tests. However, also laboratory methods come with inherent limitations, and it is essential for the clinician to know and recognize typical pitfalls. Most factors potentially impairing the quality of hormone measurements are introduced in the preanalytical phase, i.e. before the hormones are measured by the laboratory. For example, the timing of blood drawing with respect to circadian rhythm, stress, and medication can have an influence on hormone concentrations. During the actual analysis of the hormones, cross-reactions with molecules present in the sample presenting the same or similar epitopes than the intended analyte may affect immunoassays. Interference can also come from heterophilic or human anti-animal antibodies. Unexpected problems can also be due to popular nutritional supplements which interfere with the measurement procedures. An important example in this respect is the interference from biotin. It became only clinically visible when the use of this vitamin became popular among patients. The extreme serum concentrations reached when patients take it as a supplement can lead to incorrect measurements in immunoassays employing the biotin-streptavidin system. To some extent, hormone analyses using liquid chromatography mass spectrometry (LCMS) can overcome problems, although availability and cost-effectiveness of this method still imposes restrictions. In the post-analytical phase, appropriateness of reference intervals and cut-offs with respect to the specific analytical method used is of outmost importance. Furthermore, for interpretation, additional biological and pharmacological factors like BMI, age and concomitant diseases must be considered to avoid misinterpretation of the measured concentrations. It is important for the clinician and the laboratory to recognize when one or more laboratory values do not match the clinical picture. In an interdisciplinary approach, the search for the underlying cause should be initiated.

Recommendations for the measurement of sexual steroids in clinical practice. A position statement of SEQCML/SEEN/SEEP

The proper clinical approach to a wide range of disorders relies on the availability of accurate, reproducible laboratory results for sexual steroids measured using methods with a high specificity and sensitivity. The chemiluminescent immunoassays currently available have analytical limitations with significant clinical implications. This position statement reviews the current limitations of laboratory techniques for the measurement of estradiol and testosterone and their impact on diverse clinical scenarios. A set of recommendations are provided to incorporate steroid hormone analysis by mass spectrometry in national health systems. International societies have recommended this methodology for a decade.

Executive summary of the position statement of the Spanish Societies SEQCML/SEEN/SEEP. Recommendations for the measurement of sex steroids in clinical practice

Accurate measurement of sex steroids, particularly testosterone and estradiol, is relevant for the diagnosis and treatment of a wide range of conditions. Unfortunately, current chemiluminescent immunoassays have analytical limitations with important clinical consequences. This document reviews the current state of clinical assays for estradiol and testosterone measurements and their potential impact in different clinical situations. It also includes a series of recommendations and necessary steps to introduce steroid analysis by mass spectrometry into national health systems, a methodology recommended for more than a decade by international societies.

Falsely Elevated Estradiol Results in a 62-Year-Old Male Patient

Falsely increased estradiol levels can lead to unnecessary tests and therapeutic interventions. Here, we present a case of a 62-year-old man with falsely elevated estradiol, which led to subsequent follow-up testing and prescriptions. Alternative immunoassay testing, in conjunction with Scantibodies' blocking reagents, polyethylene glycol precipitation, and liquid chromatography-tandem mass spectrometry confirmation demonstrated that the falsely elevated estradiol was due to the presence of macro-estradiol. This report emphasizes the importance of recognizing analytical interferences in immunoassays to appropriately manage subsequent testing and patient care.

Falsely elevated serum estradiol in woman of reproductive age led to unnecessary intervention and delayed fertility opportunity: a case report and literature review

BACKGROUND

The optimal management of patients in reproductive endocrinology relies on the accuracy and validity of sex hormone assays. Endogenous or exogenous substances can compete with the analyte. This competition can result in interfering errors and falsely indicate elevated serum levels. Obvious interference in estradiol assays appears to occur rarely. Consequently, clinicians who are not familiar with the potential of interference could be misled. In addition to unnecessary investigations and interventions and severe mental stress, falsely elevated estradiol results can result in missed or delayed fertility opportunities.

CASE

A 28-year-old female with pregnancy demand was diagnosed with polycystic ovary syndrome, Hashimoto's thyroiditis and subclinical hypothyroidism. She was found to have persistently elevated levels of serum estradiol in the early follicular phase (between 527 and 642 pg/mL). Screening workup was performed for nearly 11 months to find the causes. Serum tumor biomarkers were normal. Abdominal and pelvic computed tomography were negative for adrenal or adnexal masses. A left mesosalpinx cyst and benign pathological results were achieved by laparoscopic surgery. Hormonal substances and dietary supplements were absent, as determined by dietary records. Ultrasound confirmed follicles could grow slowly and eventually ovulate. Falsely elevated estradiol levels were suspected due to the discrepancy among high estradiol levels, follicle growth and normal gonadotropin levels. Immunological interference by heterophile antibody was finally verified by two competitive chemiluminescent immunoassay platforms (estradiol levels in the early follicle phase: 619 pg/mL, Siemens ADVIA CENTAUR and 60 pg/mL, Beckman, DxI 800). Successful clinical pregnancy was eventually achieved by combining induced ovulation, ultrasound monitoring and intercourse guidance.

CONCLUSIONS

Analytical interference and laboratory error should be suspicious at first when the clinical characteristics contradict the laboratory results of serum hormones. Measuring serum estradiol with another immunoassay platform is an easy and non-time-consuming method to exclude the heterophile interfering.

Simultaneous Quantification of Aromatase Inhibitors and Estrogens in Postmenopausal Breast Cancer Patients

CONTEXT

Currently there are no assays that can simultaneously quantify serum levels of the third-generation aromatase inhibitors (AIs): letrozole, anastrozole, and exemestane, and the ultra-low levels of estrogens in postmenopausal breast cancer patients on AI treatment. Such measurements may be pivotal for the determination of optimal and individualized treatment regimens. We aimed at developing a liquid chromatography-tandem mass spectrometry (MS/MS) method for simultaneous assessment of letrozole, anastrozole, exemestane, and 17-hydroxyexemestane as well as subpicomolar levels of estradiol and estrone.

METHODS

Internal standards, calibrators, serum samples, and quality controls were in fully automated steps transferred to a deep-well plate for a 2-step liquid-liquid extraction. The extracts were reconstituted and analytes were separated chromatographically using 2 serially coupled columns, then subject to MS/MS in electrospray ionization mode. The method was thoroughly validated and is traceable to 2 accredited estrogen methods.

RESULTS

The measurement range for estrone and estradiol was 0.2 to 12 000 pmol/L and 0.8 to 13 000 pmol/L, and covered the expected therapeutic range for the AIs. All analytes had a precision of less than or equal to 13%, and accuracies within 100 ± 8%. As proof of concept, AI and estrogen levels were determined in serum samples from postmenopausal breast cancer patients under treatment.

CONCLUSION

We present here an assay suitable for the simultaneous measurement of serum levels of all third-generation AIs and ultra-low levels of estrogens, providing a powerful new tool to study drug efficacy and compliance. The method is highly valuable for postmenopausal patients whose pretreatment estradiol levels are below the threshold of detection for most routine assays, but still require suppression.

Hormone Immunoassay Interference: A 2021 Update

Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.

Falsely elevated serum estradiol due to heterophile antibody interference: a case report

Falsely elevated estradiol is rare, may result from heterophile antibody interference, and can result in unnecessary investigation and intervention. We present the case of a 56-year-old female with falsely elevated estradiol levels inconsistent with her overall clinical picture, which ultimately led to an unnecessary surgical procedure. With the use of alternative analytical platforms and a heterophile antibody blocking agent, we determined the false elevation was due to heterophile antibody interference. Clinicians must suspect and investigate for laboratory error when the clinical picture contradicts laboratory results.

Analytical bias of automated immunoassays for six serum steroid hormones assessed by LC-MS/MS

Introduction

There is a growing amount of evidence showing the significant analytical bias of steroid hormone immunoassays, but large number of available immunoassays makes conduction of a single comprehensive study of this issue hardly feasible. Aim of this study was to assess the analytical bias of six heterogeneous immunoassays for serum aldosterone, cortisol, dehydroepiandrosterone sulphate (DHEAS), testosterone, 17-hydroxyprogesterone (OHP) and progesterone using the liquid chromatography coupled to the tandem mass spectrometry (LC-MS/MS).

Materials and methods

This method comparison study included 49 serum samples. Testosterone, DHEAS, progesterone and cortisol immunoassays were performed on the Abbott Architect i2000SR or Alinity i analysers (Abbott Diagnostics, Chicago, USA). DiaSorin’s Liaison (DiaSorin, Saluggia, Italy) and DIAsource’s ETI-Max 3000 analysers (DIAsource ImmunoAssays, Louvain-La-Neuve, Belgium) were chosen for aldosterone and OHP immunoassay testing, respectively. All immunoassays were evaluated against the LC-MS/MS assay relying on the commercial kit (Chromsystems, Gräfelfing, Germany) and LCMS-8050 analyser (Shimadzu, Kyoto, Japan). Analytical biases were calculated and method comparison was conducted using weighted Deming regression analysis.

Results

Depending on the analyte and specific immunoassay, mean relative biases ranged from -31 to + 137%. Except for the cortisol, immunoassays were positively biased. For none of the selected steroids slope and intercept 95% confidence intervals simultaneously contained 0 and 1, respectively.

Conclusions

Evaluated immunoassays failed to satisfy requirements for methods’ comparability and produced significant analytical biases in respect to the LC-MS/MS assay, especially at low concentrations.

Therapeutic Drug Monitoring of Oral Anti-Hormonal Drugs in Oncology

Oral anti-hormonal drugs are essential in the treatment of breast and prostate cancer. It is well known that the interpatient variability in pharmacokinetic exposure is high for these agents and exposure-response relationships exist for many oral anti-hormonal drugs. Yet, they are still administered at fixed doses. This could lead to underdosing and thus suboptimal efficacy in some patients, while other patients could be overdosed resulting in unnecessary side effects. Therapeutic drug monitoring (TDM), individualized dosing based on measured blood concentrations of the drug, could therefore be a valid option to further optimize treatment. In this review, we provide an overview of relevant clinical pharmacokinetic and pharmacodynamic characteristics of oral anti-hormonal drugs in oncology and translate these into practical guidelines for TDM. For some agents, TDM targets are not well established yet and as a reference the median pharmacokinetic exposure could be targeted (exemestane: minimum plasma concentration (C_min) 4.1 ng/mL and enzalutamide: C_min 11.4 mg/L). However, for most drugs, exposure-efficacy analyses could be translated into specific targets (abiraterone: C_min 8.4 ng/mL, anastrozole: C_min 34.2 ng/mL, and letrozole: C_min 85.6 ng/mL). Moreover, prospective clinical trials have shown TDM to be feasible for tamoxifen, for which the exposure-efficacy threshold of its active metabolite endoxifen is 5.97 ng/mL. Based on the available data, we therefore conclude that individualized dosing based on drug concentrations is feasible and promising for oral anti-hormonal drugs and should be developed further and implemented into clinical practice.

The importance of estradiol measurement in patients undergoing in vitro fertilization

Successful outcomes of in vitro fertilization (IVF) are dependent in part on successful oocyte maturation and retrieval during a controlled ovarian stimulation process, which is guided by serial ultrasound and estradiol measurements. Yet, laboratory analysis of estradiol poses challenges due to the need for accuracy and specificity across concentrations that span multiple orders of magnitude. The Endocrine Society released a 2013 position statement that called for improvements in methods to analyze estradiol, and while some progress has been made in standardization and assay specificity, further work is needed to meet the needs of patients in both the IVF setting and in other clinical contexts. This review highlights the capabilities and challenges of current laboratory methods for the analysis of estradiol in the IVF setting, including automated immunoassays and liquid chromatography-tandem mass spectrometry, and discusses current efforts to improve the analytical sensitivity and standardization of estradiol assays. Clinical laboratorians should be aware of the limitations of current estradiol assays and select appropriate methods for the measurement of estradiol in their patient population.

Challenges of measuring accurate estradiol levels in aromatase inhibitor-treated postmenopausal breast cancer patients on vaginal estrogen therapy

Breast cancer patients who are taking adjuvant Aromatase Inhibitor (AI) therapy typically have extremely low estradiol levels, which are undetectable by routine clinical laboratories. Thus, it becomes difficult to assess the safety of interventions such as low‐dose vaginal estrogen, which may increase estradiol levels. In this study, we aimed to assess the utility of enzyme‐linked immunosorbent assay (ELISA) to measure low estradiol concentrations in breast cancer survivors on AI therapy treated with either vaginal estrogen or lubricant for atrophic vaginitis as a part of clinical trial. The samples were tested using two independent ELISA kits. Some of the samples were also evaluated using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) for comparison. We found that while the results by ELISA were reproducible, they were not accurate when compared to LC‐MS/MS. It is possible that medications or supplements may cross‐react with the ELISA reagents and confound the assessment; however, those were often not the reason for the discrepancy. Our results highlight the need for developing novel, reliable, and clinically accessible assays to measure ultra‐low estradiol levels to improve care of breast cancer survivors. At this stage, based on our findings, we recommend using MS‐based assays for estradiol quantitation for breast cancer survivors, whenever necessary.