Effect of metformin and lifestyle intervention on adipokines and hormones in breast cancer survivors: a pooled analysis from two randomized controlled trials

PURPOSE

We investigated the effect of metformin and lifestyle intervention on metabolic, inflammatory, and steroid biomarkers of breast cancer (BC) recurrence risk in two intervention trials among BC survivors with overweight or obesity.

METHODS

Baseline and follow-up serum samples collected during the two trials were analyzed and data pooled. The USA trial (Reach for Health) included postmenopausal BC survivors (n = 333) randomly assigned to 6-month metformin vs placebo and lifestyle intervention (LSI) vs control (2 × 2 factorial design). The Italian trial (MetBreCS) included BC survivors (n = 40) randomized to 12-month metformin vs placebo. Insulin resistance (HOMA-IR), adipokines, cytokines, and steroids were measured.

RESULTS

Metformin compared to placebo showed a favorable decrease in leptin (- 8.8 vs - 3.5 ng/mL; p < 0.01) and HOMA-IR (- 0.48 vs - 0.25; p = 0.03), and an increase in SHBG (2.80 vs 1.45 nmol/L; p < 0.01). Excluding women taking aromatase inhibitors, metformin (n = 84) compared to placebo (n = 99) decreased estradiol (- 4 vs 0 pmol/L; p < 0.01), estrone (- 8 vs 2 pmol/L; p < 0.01) and testosterone (- 0.1 vs 0 nmol/L-; p = 0.02). LSI favorably affected adiponectin (0.45 vs - 0.06 ug/mL; p < 0.01), leptin (- 10.5 vs - 4.4 ng/mL; p < 0.01), HOMA-IR (- 0.6 vs 0.2; p = 0.03), and SHBG (2.7 vs 1.1 nMol/L; p = 0.04) compared to controls. The strongest impact was observed combining metformin with LSI on adipokines, CRP, SHBG, and estrogens.

CONCLUSIONS

Supportive healthy lifestyle programs combined with metformin to achieve maximal risk reduction among BC cancer survivors are recommended, especially for those with obesity in menopause.

Superior suppression of serum estrogens during neoadjuvant breast cancer treatment with letrozole compared to exemestane

PURPOSE

The aromatase inhibitor letrozole and the aromatase inactivator exemestane are two of the most pivotal cancer drugs used for endocrine treatment of ER-positive breast cancer in all phases of the disease. Although both drugs inhibit CYP19 (aromatase) and have been used for decades, a direct head-to-head, intra-patient-cross-over comparison of their ability to decrease estrogen synthesis in vivo is still lacking.

METHODS

Postmenopausal breast cancer patients suitable for neoadjuvant endocrine therapy were randomized to receive either letrozole (2.5 mg o.d.) or exemestane (25 mg o.d.) for an initial treatment period, followed by a second treatment period on the alternative drug (intra-patient cross-over study design). Serum levels of estrone (E1), estradiol (E2), letrozole, exemestane, and 17-hydroxyexemestane were quantified simultaneously using a novel, ultrasensitive LC-MS/MS method established in our laboratory.

RESULTS

Complete sets of serum samples (baseline and during treatment with letrozole or exemestane) were available from 79 patients, including 40 patients starting with letrozole (cohort 1) and 39 with exemestane (cohort 2). Mean serum estrone and estradiol levels in cohort 1 were 174 pmol/L and 46.4 pmol/L at baseline, respectively. Treatment with letrozole suppressed serum E1 and E2 to a mean value of 0.2 pmol/L and 0.4 pmol/L (P < 0.001). After the cross-over to exemestane, mean serum levels of E1 and E2 increased to 1.4 pmol/L and 0.7 pmol/L, respectively. In cohort 2, baseline mean serum levels of E1 and E2 were 159 and 32.5 pmol/L, respectively. Treatment with exemestane decreased these values to 1.8 pmol/L for E1 and 0.6 pmol/L for E2 (P < 0.001). Following cross-over to letrozole, mean serum levels of E1 and E2 were significantly further reduced to 0.1 pmol/L and 0.4 pmol/L, respectively. Serum drug levels were monitored in all patients throughout the entire treatment and confirmed adherence to the protocol and drug concentrations within the therapeutic range for all patients. Additionally, Ki-67 values decreased significantly during treatment with both aromatase inhibitors, showing a trend toward a stronger suppression in obese women.

CONCLUSION

To the best of our knowledge, we present here for the first time a comprehensive and direct head-to-head, intra-patient-cross-over comparison of the aromatase inhibitor letrozole and the aromatase inactivator exemestane concerning their ability to suppress serum estrogen levels in vivo. All in all, our results clearly demonstrate that letrozole therapy results in a more profound suppression of serum E1 and E2 levels compared to exemestane.

Deep phenotyping of pubertal development in Norwegian children: the Bergen Growth Study 2

BACKGROUND

The Bergen Growth Study 2 (BGS2) aims to characterise somatic and endocrine changes in healthy Norwegian children using a novel methodology.

SUBJECTS AND METHODS

A cross-sectional sample of 1285 children aged 6-16 years was examined in 2016 using novel objective ultrasound assessments of breast developmental stages and testicular volume in addition to the traditional Tanner pubertal stages. Blood samples allowed for measurements of pubertal hormones, endocrine disruptive chemicals, and genetic analyses.

RESULTS

Ultrasound staging of breast development in girls showed a high degree of agreement within and between observers, and ultrasound measurement of testicular volume in boys also showed small intra- and interobserver differences. The median age was 10.4 years for Tanner B2 (pubertal onset) and 12.7 years for menarche. Norwegian boys reached a pubertal testicular volume at a mean age of 11.7 years. Continuous reference curves for testicular volume and sex hormones were constructed using the LMS method.

CONCLUSIONS

Ultrasound-based assessments of puberty provided novel references for breast developmental stages and enabled the measurement of testicular volume on a continuous scale. Endocrine z-scores allowed for an intuitive interpretation of changing hormonal levels during puberty on a quantitative scale, which, in turn, provides opportunities for further analysis of pubertal development using machine-learning approaches.

Sex Hormones and Adrenal Steroids: Biological Variation Estimated Using Direct and Indirect Methods

BACKGROUND

Biological variation (BV) data may be used to develop analytical performance specifications (APS), reference change values (RCV), and support the applicability of population reference intervals. This study estimates within-subject BV (CVI) for several endocrine biomarkers using 3 different methodological approaches.

METHODS

For the direct method, 30 healthy volunteers were sampled weekly for 10 consecutive weeks. Samples were analyzed in duplicate for 17-hydroxyprogesterone (17-OHP), androstenedione, cortisol, cortisone, estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), and testosterone. A CV-ANOVA with outlier removal and a Bayesian model were applied to derive the CVI. For estradiol, FSH and LH, only the male subgroup was included. In the indirect method, using the same analytes and groups, pairs of sequential results were extracted from the laboratory information system. The total result variation for individual pairs was determined by identifying a central gaussian distribution in the ratios of the result pairs. The CVI was then estimated by removing the effect of analytical variation.

RESULTS

The estimated CVI from the Bayesian model (μCVP(i)) in the total cohort was: 17-OHP, 23%; androstenedione, 20%; cortisol, 18%; cortisone, 11%; SHBG, 7.4%; testosterone, 16%; and for the sex hormones in men: estradiol, 14%; FSH, 8%; and LH, 26%. CVI-heterogeneity was present for most endocrine markers. Similar CVI data were estimated using the CV-ANOVA and the indirect method.

CONCLUSIONS

Similar CVI data were obtained using 2 different direct and one indirect method. The indirect approach is a low-cost alternative ensuring implementation of CVI data applicable for local conditions.

Reference Curves for Pediatric Endocrinology: Leveraging Biomarker Z-Scores for Clinical Classifications

CONTEXT

Hormone reference intervals in pediatric endocrinology are traditionally partitioned by age and lack the framework for benchmarking individual blood test results as normalized z-scores and plotting sequential measurements onto a chart. Reference curve modeling is applicable to endocrine variables and represents a standardized method to account for variation with gender and age.

OBJECTIVE

We aimed to establish gender-specific biomarker reference curves for clinical use and benchmark associations between hormones, pubertal phenotype, and body mass index (BMI).

METHODS

Using cross-sectional population sample data from 2139 healthy Norwegian children and adolescents, we analyzed the pubertal status, ultrasound measures of glandular breast tissue (girls) and testicular volume (boys), BMI, and laboratory measurements of 17 clinical biomarkers modeled using the established "LMS" growth chart algorithm in R.

RESULTS

Reference curves for puberty hormones and pertinent biomarkers were modeled to adjust for age and gender. Z-score equivalents of biomarker levels and anthropometric measurements were compiled in a comprehensive beta coefficient matrix for each gender. Excerpted from this analysis and independently of age, BMI was positively associated with female glandular breast volume (β = 0.5, P < 0.001) and leptin (β = 0.6, P < 0.001), and inversely correlated with serum levels of sex hormone-binding globulin (SHBG) (β = -0.4, P < 0.001). Biomarker z-score profiles differed significantly between cohort subgroups stratified by puberty phenotype and BMI weight class.

CONCLUSION

Biomarker reference curves and corresponding z-scores provide an intuitive framework for clinical implementation in pediatric endocrinology and facilitate the application of machine learning classification and covariate precision medicine for pediatric patients.

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.

Bedtime Salivary Cortisol as a Screening Test for Cushing Syndrome in Children

Background

Diagnosing Cushing syndrome (CS) can be challenging. The 24-hour urine free cortisol (UFC) measurement is considered gold standard. This is a laborious test, dependent on correct urine collection. Late-night salivary cortisol is easier and is used as a screening test for CS in adults, but has not been validated for use in children.

Objective

To define liquid chromatography tandem mass spectrometry (LC-MS/MS)-based cutoff values for bedtime and morning salivary cortisol and cortisone in children, and validate the results in children with and without CS.

Methods

Bedtime and morning salivary samples were collected from 320 healthy children aged 4 to 16 years. Fifty-four patients from the children’s outpatient obesity clinic and 3 children with pituitary CS were used for validation. Steroid hormones were assayed by LC-MS/MS. Cutoff levels for bedtime salivary cortisol and cortisone were defined by the 97.5% percentile in healthy subjects.

Results

Bedtime cutoff levels for cortisol and cortisone were 2.4 and 12.0 nmol/L, respectively. Applying these cutoff levels on the verification cohort, 1 child from the obesity clinic had bedtime salivary cortisol exceeding the defined cutoff level, but normal salivary cortisone. All 3 children with pituitary CS had salivary cortisol and cortisone far above the defined bedtime cutoff levels. Healthy subjects showed a significant decrease in salivary cortisol from early morning to bedtime.

Conclusions

We propose that bedtime salivary cortisol measured by LC-MS/MS with a diagnostic threshold above 2.4 nmol/L can be applied as a screening test for CS in children. Age- and gender-specific cutoff levels are not needed.

Hormone References for Ultrasound Breast Staging and Endocrine Profiling to Detect Female Onset of Puberty

CONTEXT

Application of ultrasound (US) to evaluate attainment and morphology of glandular tissue provides a new rationale for evaluating onset and progression of female puberty, but currently no hormone references complement this method. Furthermore, previous studies have not explored the predictive value of endocrine profiling to determine female puberty onset.

OBJECTIVE

To integrate US breast staging with hypothalamic-pituitary-gonadal hormone references and test the predictive value of an endocrine profile to determine thelarche.

DESIGN SETTING AND PARTICIPANTS

Cross-sectional sample of 601 healthy Norwegian girls, ages 6 to 16 years.

MAIN OUTCOME MEASURES

Clinical and ultrasound breast evaluations were performed for all included girls. Blood samples were analyzed by immunoassay and ultrasensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify estradiol (E2) and estrone (E1) from the subpicomolar range.

RESULTS

References for E2, E1, luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin were constructed in relation to chronological age, Tanner stages, and US breast stages. An endocrine profile index score derived from principal component analysis of these analytes was a better marker of puberty onset than age or any individual hormone, with receiver-operating characteristic area under the curve 0.91 (P < 0.001). Ultrasound detection of nonpalpable glandular tissue in 14 out of 264 (5.3%) girls with clinically prepubertal presentation was associated with significantly higher median serum levels of E2 (12.5 vs 4.9 pmol/L; P < 0.05) and a distinct endocrine profile (arbitrary units; P < 0.001).

CONCLUSIONS

We provide the first hormone references for use with US breast staging and demonstrate the application of endocrine profiling to improve detection of female puberty onset.

An Ultrasensitive Routine LC-MS/MS Method for Estradiol and Estrone in the Clinically Relevant Sub-Picomolar Range

BACKGROUND

Current analytical routine methods lack the sensitivity to monitor plasma estrogen levels in breast cancer patients treated with aromatase inhibitors. Such monitoring is warranted for premenopausal patients treated with an aromatase inhibitor and an LH-releasing hormone analogue in particular. Therefore, we aimed to develop a routine tandem mass spectroscopy combined with liquid chromatography (LC-MS/MS) method for estradiol (E2) and estrone (E1) for use in the sub-picomolar range.

METHOD

Calibrators, quality controls (QC), or serum samples were spiked with isotope-labeled internal standard and purified by liquid-liquid extraction. The reconstituted extracts were analyzed by LC-MS/MS in negative electrospray ionization mode. QCs at 6 levels made from pooled patient sera were used to validate the accuracy, sensitivity, and precision of the method.

RESULTS

We achieved limits of quantification of 0.6 pmol/L (0.16 pg/mL) for E2 and 0.3 pmol/L (0.07 pg/mL) for E1. The coefficient of variation was below 9.0% at all QC levels for E2 (range, 1.7-153 pmol/L), and below 7.8% for E1 (range, 1.7-143 pmol/L). The method is traceable to the E2 reference standard BCR576. Reference ranges for E2 and E1 in healthy, postmenopausal women were obtained, for E2: 3.8 to 36 pmol/L, for E1: 22 to 122 pmol/L. We measured and confirmed ultra-low E2 and E1 concentrations in sera from patients on the aromatase inhibitors letrozole or exemestane.

CONCLUSION

This ultrasensitive LC-MS/MS method is suitable for routine assessment of serum E1 and E2 levels in breast cancer patients during estrogen suppression therapy. The method satisfies all requirements for measurement of E2 in the clinical setting as stated by the Endocrine Society in 2013.

PRECIS

We report an ultrasensitive LCMS/MS routine assay that measures pretreatment and suppressed levels of estradiol/estrone during aromatase inhibitor treatment of postmenopausal breast cancer patients.

Testicular Ultrasound to Stratify Hormone References in a Cross-Sectional Norwegian Study of Male Puberty

CONTEXT

Testicular growth represents the best clinical variable to evaluate male puberty, but current pediatric hormone references are based on chronological age and subjective assessments of discrete puberty development stages. Determination of testicular volume (TV) by ultrasound provides a novel approach to assess puberty progression and stratify hormone reference intervals.

OBJECTIVE

The objective of this article is to establish references for serum testosterone and key hormones of the male pituitary-gonadal signaling pathway in relation to TV determined by ultrasound.

DESIGN, SETTING, AND PARTICIPANTS

Blood samples from 414 healthy Norwegian boys between ages 6 and 16 years were included from the cross-sectional "Bergen Growth Study 2." Participants underwent testicular ultrasound and clinical assessments, and serum samples were analyzed by liquid chromatography tandem-mass spectrometry and immunoassays.

MAIN OUTCOME MEASURES

We present references for circulating levels of total testosterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin in relation to TV, chronological age, and Tanner pubic hair stages.

RESULTS

In pubertal boys, TV accounted for more variance in serum testosterone levels than chronological age (Spearman r = 0.753, P < .001 vs r = 0.692, P < .001, respectively). Continuous centile references demonstrate the association between TV and hormone levels during puberty. Hormone reference intervals were stratified by TV during the pubertal transition.

CONCLUSIONS

Objective ultrasound assessments of TV and stratification of hormone references increase the diagnostic value of traditional references based on chronological age or subjective staging of male puberty.

Blood steroid levels predict survival in endometrial cancer and reflect tumor estrogen signaling

OBJECTIVE

Blood-based biomarkers are attractive due to ease of sampling and standardized measurement technology, reducing obstacles to clinical implementation. The objective of this study was to evaluate a clinically available method of steroid hormone measurement for its prognostic potential in endometrial cancer.

METHODS

We quantified seven steroid hormones by liquid chromatography-tandem mass spectrometry in 100 endometrial cancer patients from a prospective cohort. Abdominal fat distribution was assessed from abdominal computed tomography (CT) scans. Steroid hormone levels were compared to clinical characteristics, fat distribution and gene expression in primary tumor samples.

RESULTS

Low levels of 17OH-progesterone, 11-deoxycortisol and androstenedione were associated with aggressive tumor characteristics and poor disease specific survival (p = .003, p = .001 and p = .02 respectively). Adjusting for preoperative risk based on histological type and grade, low 17OH-progesterone and 11-deoxycortisol independently predicted poor outcome with hazard ratios of 2.69 (p = .033, 95%CI: 1.09-6.68) and 3.40 (p = .020, 1.21-9.51), respectively. Tumors from patients with low steroid level displayed increased expression of genes related to mitosis and cell cycle progression, whereas high steroid level was associated with upregulated estrogen signaling and genes associated with inflammation. Estrone and estradiol correlated to abdominal fat volume in all compartments (total, visceral, subcutaneous, p < .001 for all), but not to the visceral fat proportion. Patients with higher levels of circulating estrogens had increased expression of estrogen signaling related genes.

CONCLUSION

Low levels of certain endogenous steroids are associated with aggressive tumor traits and poor survival and may provide preoperative information independent of histological biomarkers already in use.

Adrenal Venous Sampling for Assessment of Autonomous Cortisol Secretion

CONTEXT

Autonomous cortisol secretion (ACS) can be unilateral or bilateral irrespective of the presence of an adrenal tumor. A reliable method to distinguish between unilateral and bilateral ACS is lacking.

OBJECTIVE

Evaluate the use of adrenal venous sampling (AVS) to distinguish between unilateral and bilateral ACS.

DESIGN AND METHODS

This was a prospective study of AVS in patients with adrenal tumors who received a diagnosis of ACS or adrenal Cushing syndrome (CS). Unilateral secretion was defined as >2.3-fold difference in cortisol levels between the two adrenal veins. Metanephrine levels were used to ascertain correct catheter position. Results were correlated with findings on CT and iodine-131-cholesterol scintigraphy.

RESULTS

Thirty-nine patients underwent AVS; there were no complications. The procedure was inconclusive in six patients and repeated with success in one, giving a success rate of 85%, and leaving 34 procedures for evaluation (adrenal CS, n = 2; ACS, n = 32). Of 14 patients with bilateral tumors, 10 had bilateral and 4 had unilateral overproduction. Of 20 patients with unilateral tumors, 11 had lateralization to the side of the tumor and the remaining had bilateral secretion. Cholesterol scintigraphy findings were concordant with those of AVS in 13 of 18 cases (72%) and discordant in 5 (28%).

CONCLUSION

Laterality of ACS does not always correspond to findings on CT images. AVS is a safe and valuable tool for differentiation between unilateral and bilateral cortisol secretion and should be considered when operative treatment of ACS is a possibility.

Efficacy of adrenal venous sampling is increased by point of care cortisol analysis

Primary aldosteronism (PA) is a common cause of secondary hypertension and is caused by unilateral or bilateral adrenal disease. Treatment options depend on whether the disease is lateralized or not, which is preferably evaluated with selective adrenal venous sampling (AVS). This procedure is technically challenging, and obtaining representative samples from the adrenal veins can prove difficult. Unsuccessful AVS procedures often require reexamination. Analysis of cortisol during the procedure may enhance the success rate. We invited 21 consecutive patients to participate in a study with intra-procedural point of care cortisol analysis. When this assay showed nonrepresentative sampling, new samples were drawn after redirection of the catheter. The study patients were compared using the 21 previous procedures. The intra-procedural cortisol assay increased the success rate from 10/21 patients in the historical cohort to 17/21 patients in the study group. In four of the 17 successful procedures, repeated samples needed to be drawn. Successful sampling at first attempt improved from the first seven to the last seven study patients. Point of care cortisol analysis during AVS improves success rate and reduces the need for reexaminations, in accordance with previous studies. Successful AVS is crucial when deciding which patients with PA will benefit from surgical treatment.