Interpreting plasma estrogen levels in breast cancer: caution needed

Effects of vaginal estrogen on serum estradiol during aromatase inhibitor therapy in breast cancer patients with vulvovaginal atrophy: a prospective trial

PURPOSE

This study aimed to analyze changes in serum estradiol (E2) levels during concurrent vaginal estradiol therapy and adjuvant letrozole in postmenopausal breast cancer (BC) patients with vulvovaginal atrophy (VVA). Secondary objectives included assessing the effects of therapy on vaginal atrophy, quality of life (QoL) and menopause-related symptoms.

METHODS

20 postmenopausal patients undergoing adjuvant letrozole therapy and experiencing VVA symptoms were treated with vaginal estradiol for 12 weeks. Gynecologic examination and symptom screening were conducted at baseline and after 12 weeks. Serum E2 levels were analyzed at baseline, and at two, four, eight, and 12 weeks. E2 levels were measured using both a routine liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and a highly sensitive (hsE2-MS) LC-MS/MS method.

RESULTS

At baseline, serum E2 levels, measured with hsE2-MS, were below the lower limit of quantification (LLOQ) in all patients. E2 remained below LLOQ throughout the treatment period in three patients (15%). Persistent E2 elevation above LLOQ was observed in six patients (30%), while isolated E2 elevations occurred in 10 patients (50%). One patient experienced transient E2 elevation in two sporadic measurements. Serum E2 variations were shown by using both LC-MS/MS methods. Vaginal pH, vaginal maturation index (VMI), and VVA symptoms significantly improved during treatment.

CONCLUSION

Intravaginal estradiol therapy (10ug) during adjuvant letrozole resulted in transient increases in systemic E2 levels among early BC patients with VVA. Highly sensitive LC-MS/MS is a promising method for monitoring E2 levels during aromatase inhibitor (AI) therapy.

Mimicking women's endocrine milieu in mice for women's health-related studies

To improve preclinical studies and their translation, patient-derived xenografts (PDXs) are increasingly used. They have human-specific tumor characteristics and reflect intra and inter-tumor heterogeneity. However, the endocrine milieu differs between humans and host mice. In light of sex-specific cancer biology and a rise in endocrine-related cancers there is an urgent need to correctly reflect the hormonal milieu in PDX models. We show that female mice of NOD.Cg-Prkdc scid Il2rg tm1Wjl /SzJ (NSG) strain widely used for PDXs has 17-β-estradiol (E2) and testosterone (T) levels comparable to C57Bl6 females but higher progesterone (P4) levels. E2 levels are comparable, T levels are lower and P4 levels higher than those observed in postmenopausal women. Ovariectomy increases T to levels observed in postmenopausal women. Subcutaneous E2 and combined E2/P4 silicon pellets provide NSG females with premenopausal ovarian hormone levels. These procedures humanize the endocrine environment of experimental animals, improving PDX relevance in women's health-related research.

Menopausal symptoms in breast cancer survivors on adjuvant endocrine therapy compared with those of menopausal women

OBJECTIVES

To compare menopausal symptoms of breast cancer survivors on adjuvant endocrine therapy with those of menopausal women.

STUDY DESIGN

In a retrospective nested case-control study menopausal symptoms were compared of breast cancer survivors in pre-, peri- or post-menopause at the time of diagnosis, on tamoxifen or an aromatase inhibitor, plus a gonadotrophin-releasing hormone analogue, if pre- or peri-menopausal, and age-matched control women either in the late peri-menopause, or in surgical or in physiological post-menopause on no hormone replacement therapy. Differences between women on tamoxifen and those on aromatase inhibitors were also evaluated. Weighted and non-weighted t-tests, chi-square tests, and linear or logistic regressions were applied as appropriate.

MAIN OUTCOME MEASURES

Score on the Greene's Climacteric Scale and so of its subscales evaluating vasomotor, anxiety, depression, somatisation and sexuality symptoms.

RESULTS

A total of 99 breast cancer survivors (45 on tamoxifen, 54 on aromatase inhibitors) and 554 controls (173 in late perimenopause, 353 in natural and 28 in surgical menopause) were enrolled. The score on the Greene's Climacteric Scale was similar in cases and controls (means ± standard deviation) (21.3 ± 10.4 vs. 22.8 ± 11.5, p = 0.199), as were the subscale scores for vasomotor symptoms, anxiety, and somatisation. The depression score was lower (4.63 ± 3.3 vs. 5.98 ± 3.8; p = 0.001) in breast cancer survivors on adjuvant endocrine therapy, mainly due to a lower score of -2.132 (95 % confidence interval - 3.858/-0.407; p = 0.016) for users of aromatase inhibitors. The sexuality score was higher (1.76 ± 1.1 vs. 1.50 ± 1.1, p = 0.011) than in controls. Differences remained significant when corrected for age, menarche, body mass index, menopausal status (peri- or post-), type of menopause (natural, surgical), use of gonadotrophin-releasing hormone analogues, years of amenorrhea, smoking, alcohol use, and for breast radiotherapy, chemotherapy, tamoxifen or aromatase inhibitors. Among breast cancer survivors, women on aromatase inhibitors had lower scores for anxiety (5.75 ± 2.5vs.5.75 ± 2.5; p = 0.045) and depression (3.89 ± 2.5 vs. 5.13 ± 3.6; p = 0.046) than women on tamoxifen.

CONCLUSIONS

In breast cancer survivors, adjuvant therapy induces symptoms similar in type and intensity to those of symptomatic menopausal women. Compared with menopausal women, breast cancer survivors, particularly those on aromatase inhibitors, appear to experience less severe depressive symptoms.

Clinical significance of serum estradiol monitoring in women receiving adjuvant aromatase inhibitor for hormone receptor-positive early breast cancer

PURPOSE

The limited understanding of long-term estradiol (E2) suppression poses challenges to the effectiveness of adjuvant therapy with aromatase inhibitors (AI), necessitating comprehensive serum E2 monitoring to address this issue. Therefore, our objective was to investigate serum E2 levels in women undergoing adjuvant AI treatment and evaluate the significance of such monitoring.

PATIENTS AND METHODS

In this prospective cohort study, we recruited women who had received adjuvant AI treatment, including those who underwent ovarian function suppression (OFS). Serum E2 levels were measured using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The primary endpoint was the proportion of women with E2 levels exceeding 2.72 pg/mL, indicating inadequate suppression achieved with AI therapy.

RESULTS

A total of 706 patients were enrolled, including 482 women with OFS in combination with AI. Among them, 116 women (16.4 %) exhibited E2 levels exceeding 2.72 pg/mL. The majority of serum E2 elevations (77.6 %) occurred within the first two years of initiating endocrine therapy. Younger age, no prior chemotherapy, shorter duration of the current treatment regimen, and lower follicle stimulating hormone (FSH) levels were associated with inadequate E2 suppression. Serum E2 concentrations demonstrated dynamic variations and occasional rebound following adjuvant AI therapy.

CONCLUSIONS

Despite receiving adjuvant AI treatment for nearly two years, a certain proportion of patients failed to achieve the adequate threshold of E2 suppression. Our findings emphasize the significance of monitoring serum E2 levels during adjuvant AI therapy, particularly within the first two years. Further research is imperative to facilitate a more comprehensive comprehension of E2 monitoring.

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.

Clinically Relevant Laboratory Monitoring of Gender-Affirming Hormone Therapy in Transgender People-Experiences from a Teaching Hospital in the Netherlands

BACKGROUND

Transgender care is shifting from academic to nonacademic settings leading to use of common (immunoassay) compared to sophisticated (mass spectrometry) methods to monitor estradiol and testosterone during gender-affirming hormone therapy (GAHT). The type of assay can influence results and have significant implications for clinical decision making. An evidence gap is present in recommendations regarding the assay needed to monitor GAHT. The present study aimed to summarize current evidence and evaluate immunoassay estradiol and testosterone concentrations in transgender people visiting a nonacademic hospital for GAHT.

METHODS

Clinical practice guidelines on GAHT and scientific literature on assay methodologies were screened and summarized. Laboratory and medical data from 252 patients who visited the transgender outpatient clinic of the Maasstad Hospital for GAHT between 2020 and 2022 were retrospectively analyzed.

RESULTS

Our research showed that the most used clinical practice guidelines for GAHT provide hormonal target values without recommending a preferred method. A comprehensive literature search on agreement between immunoassay and mass spectrometry showed substantial heterogeneity in results. Retrospective analysis of our immunoassay measured data in transgender people showed hormonal changes during GAHT that are to be expected from the medication used.

CONCLUSIONS

We demonstrate that laboratory monitoring of GAHT in a nonacademic hospital can be done safely by immunoassay in most cases. Only in cases where clinical observation is discordant with the hormonal results do more sophisticated methods need to be deployed. A best practice model was proposed for transgender care in nonacademic hospitals.

Selection of appropriate biomarkers to monitor effectiveness of ovarian function suppression in pre-menopausal patients with ER+ breast cancer

Use of gonadotropin-releasing hormone (GnRH) agonists has been widely adopted to provide reversible ovarian function suppression for pre-menopausal breast cancer patients who are also receiving aromatase inhibitor or tamoxifen therapy based on results of 25 randomized trials representing almost 15,000 women demonstrating a survival benefit with this approach. Past clinical trials designed to establish the efficacy of GnRH agonists have monitored testosterone in the prostate cancer setting and estradiol in the breast cancer setting. We explore the merits of various biomarkers including estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) and their utility for informing GnRH agonist treatment decisions in breast cancer. Estradiol remains our biomarker of choice in ensuring adequate ovarian function suppression with GnRH agonist therapy among pre-menopausal women with breast cancer. We recommend future trials to continue to focus on estradiol levels as the primary endpoint, as they have in the past.

Safety and Serum Estradiol Levels in Hormonal Treatments for Vulvovaginal Atrophy in Breast Cancer Survivors: A Systematic Review and Meta-Analysis

Vulvo-vaginal atrophy (VVA) or genitourinary syndrome of menopause (GSM) is a common condition among breast cancer (BC) patients, especially those undergoing antiestrogen therapy. Despite being an option in refractory cases, the safety of hormonal treatment remains uncertain in this population. The aim of this study was to review the safety and serum estrogen levels of hormonal therapy in patients with BC history presenting with VVA symptoms. Pubmed, Embase, and Cochrane were searched for studies comparing different hormonal treatment options for VVA in breast cancer survivors. Statistical analysis was performed using a random effects model and heterogeneity using Cochran's Q-statistic and the I2 index. We included 17 studies, of which 5 were randomized controlled trials (RCTs). Treatment modalities included in this study were topical vaginal estradiol and estriol preparations, vaginally applied testosterone, DHEA, and ospemifene. We found that, among patients treated with the estriol and estradiol preparations, there was an average increase of 7.67 pg/mL (SMD 7.67 pg/mL; 95% CI -1.00, 16.35; p < .001). Analysis of the testosterone group found temporary peaks of serum estradiol levels, but 1 study showed persistent elevation above normal postmenopausal levels. One study with prasterone revealed no elevation of serum estradiol concentration. One study with ospemifene demonstrated no increase in the risk of BC recurrence. In conclusion, among treatments available for BC survivors, low-dose vaginal estrogen showed the smallest changes in serum estradiol levels and had the most evidence, but safety remains unclear, especially for patients on aromatase inhibitors. Alternative treatments such as ospemifene need more data supporting safety and efficacy. These results suggest that concerns related to cancer recurrence should keep aiming for the lowest possible concentration.

Transdermal Delivery of Estradiol Simultaneously Possessing Rapid Release and Sustained Release Effect

Dissolving microneedle (DMN) has been researched as a drug delivery technology that improves drug molecule transportation through the skin with little discomfort. However, the sluggish drug absorption, poor skin dissolution, and lengthy time lags of DMN have limited its potential uses. The aim of this study was to design a novel DMN system for the administration of the poorly water-soluble drug, estradiol (E2), with fast skin penetration and a stable release rate for a long time. DMN containing E2 emulsion (E2-EM-DMN) and traditional DMN (T-DMN) were prepared. Rat skin was used for penetration test and guinea pig skin was used for skin irritation experiment. The drug release profiles and stability properties of these two kinds of DMNs were also investigated. High performance liquid chromatography was employed to determine the E2 content in DMN. The E2 concentration in rat plasma was achieved by a newly developed liquid chromatography-mass spectrometry method that was fast, reproducible, and specific. The height of E2-EM-DMN and T-DMN was 600 μm. The drug loading of the E2-EM-DMN and T-DMN was 667.30 ± 7.21 μg/patch and 672.56 ± 6.98 μg/patch. E2-EM-DMN possessed enough mechanical strength to penetrate the skin and caused no irritation to the skin. E2-EM-DMN could release the drug more rapidly and more continuously than T-DMN. E2-EM-DMN had good pharmaceutical stability. In summary, the E2-EM-DMN showed reliable quality and superior release performance. Emulsion-embedded DMN is an ideal transdermal delivery system for drugs.

Ovarian Function Suppression in Premenopausal Women with Concurrent Endocrine Therapy Use

INTRODUCTION

Almost 20% of patients receiving ovarian function suppression (OFS) and endocrine therapy (ET) for breast cancer treatment had inadequate OFS within the first year of treatment. Few studies have explored the long-term effectiveness of OFS to maintain estrogen suppression.

PATIENTS AND METHODS

This retrospective, single institution study examined premenopausal women with early-stage breast cancer undergoing treatment with OFS and ET. The primary endpoint was the percentage of patients with inadequate ovarian suppression (estradiol ≥10 pg/mL) during OFS cycle 2 or later. The secondary endpoint was the percentage of patients with inadequate ovarian suppression within the first cycle after OFS initiation. Differences in age, body mass index (BMI), and previous chemotherapy use were summarized via multivariable logistic regression.

RESULTS

Of the 131 patients included in the analysis, 35 (26.7%) lacked adequate suppression during OFS cycle 2 or later cycles. Patients with adequate suppression throughout treatment were more likely to be older (odds ratio [OR] 1.12 [95% CI, 1.05-1.22], P = .02), have a lower BMI (OR 0.88 [95% CI, 0.82-0.94], P < .001), and have received chemotherapy (OR 6.30 [95% CI, 2.06-20.8], P = .002). A total of 20 of 83 patients (24.1%) had an inadequately suppressed estradiol level within 35 days of OFS initiation.

CONCLUSION

This "real world" cohort demonstrates that estradiol concentrations above the postmenopausal range of the assay are frequently detected, including more than 1 year after the start of OFS. Additional research is needed to establish estradiol monitoring guidelines and optimal degree of ovarian suppression.

Measurable Serum Estradiol and Estrone in Women 36-56 Years During Adjuvant Treatment With Aromatase Inhibitors for a Hormone Receptor-Positive Breast Cancer. Case Studies and Cross-sectional Study Using an Ultra-sensitive LC-MS/MS-Method

BACKGROUND AND PURPOSE

Ovarian function recovery (OFR) during adjuvant use of an aromatase inhibitor (AI) negatively impacts breast cancer outcome. We measured serum FSH and estrogen levels in consecutive AI-users with an uncertain menopausal status during follow-up and report associated risk factors of OFR METHODS: A retrospective cross sectional observational monocentric study including breast cancer patients in follow-up using an adjuvant AI, age 36 to 56 years, with at least one serum estradiol (E2) and estrone (E1) measurement between 2013 and 2020. Estrogens were quantified using a sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS). Women on LHRH agonist were included while those with a bilateral oophorectomy or ovarian irradiation were not. We aimed to identify risk factors of OFR considering age, body mass index (BMI), previous chemotherapy and duration of AI use. Univariable analysis was used to evaluate risk factors of OFR.

RESULTS

E2/E1 levels were assessed in 207 patients with a median age of 50 years (range 36-56). 17 of 159 on AI (10.7%) and 3 of 48 on AI + LHRH (6.3%) had OFR. Seven out of 17 patients (41,2%) with OFR in the AI only group and 2 out of 3 patients (66,7%) in the AI+LHRH agonist group were in amenorrhea. Age <50 y and adjuvant chemotherapy were statistically significantly different between the OFR group and the group with postmenopausal estrogen levels.

CONCLUSION

Breast cancer patients aged 36 to56 years need to be monitored closely during adjuvant treatment with aromatase inhibitors: to confirm menopausal status, to evaluate compliance and to ensure ovarian activity remains adequately suppressed. Estrone might be a better marker then estradiol to detect ovarian reactivation.

Adjuvant Aromatase Inhibitors or Tamoxifen following Chemotherapy for Perimenopausal Breast Cancer Patients

Background

The benefit of adjuvant aromatase inhibitors (AI) vs tamoxifen has been investigated in randomized clinical trials for premenopausal and postmenopausal patients with early, estrogen receptor–positive (ER+) breast cancer. The optimal endocrine treatment for chemotherapy-treated perimenopausal women, who generally develop chemotherapy-induced amenorrhea, is uncertain.

Methods

All Dutch women who received adjuvant chemotherapy and endocrine treatment for stage I-III, ER+ (>10% positive cells), invasive breast cancer diagnosed between 2004 and 2007 were identified through the Netherlands Cancer Registry. Included women were considered perimenopausal based on an age at diagnosis of 45 to 50 years (n = 2295). For each patient, AI treatment duration relative to total endocrine treatment duration was calculated. Predominantly tamoxifen-treated patients (AI < 25%) were compared with those receiving AI and tamoxifen for a similar duration (AI 25%-75%) and those mostly using AI (AI > 75%). Adjusted hazard ratios (HRs) for recurrence-free survival (RFS) and overall survival were calculated using time-dependent Cox regression.

Results

After an average follow-up of 7.6 years, 377 RFS events occurred. Women mostly receiving AI (AI > 75%) had the best RFS (adjusted HR = 0.63, 95% confidence interval = 0.46 to 0.86) followed by those receiving AI 25% to 75% (adjusted HR = 0.85, 95% confidence interval = 0.65 to 1.12) compared with predominantly tamoxifen-treated women. Trend analyses showed that every 10% increase in AI-endocrine treatment ratio reduced RFS event risk by 5% (2-sided P_trend = .002). In total, 236 deaths occurred; hazard ratios for overall survival showed similar trends.

Conclusions

These results suggest that the best adjuvant endocrine treatment for chemotherapy-treated, ER+ breast cancer patients diagnosed aged 45-50 years consists of mainly AI followed by a switch strategy and mainly tamoxifen.

Monitoring serum estradiol levels in breast cancer patients during extended adjuvant letrozole treatment after five years of tamoxifen: a prospective trial

PURPOSE

To analyze whether monitoring serum estradiol (E2) levels using a highly sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) method may identify patients with AI failure with E2 levels below the lower limit of quantification (LLOQ) after schwitching from tamoxifen to letrozole.

METHODS

In a prospective study of breast cancer patients switching to letrozole treatment after previous tamoxifen, plasma estrogen levels were measured at baseline and after 3- and 12-months using LC-MS/MS.

RESULTS

Forty-six patients were classified postmenopausal and entered into the final analysis. Thirty-nine (85%) patients had three- and 12-month E2 concentrations below the LLOQ (5 pmol/L). In the seven patients classified as AI-failures during letrozole treatment, serum E2-MS level rose above 5 pmol/L at 3 months with a mean E2-MS 77.5 pmol/L or 12 months with a mean E2-MS 21 pmol/L. None of the baseline variables i.e., age at diagnosis, age at study entry, age at menarche, BMI, endometrial thickness, total ovarian volume, baseline FSH, E2-IA, or E2-MS were significantly associated with the risk of AI failure in logistic regression. E2 levels at baseline measured by E2-IA did not significantly correlate to the levels measured by E2-MS.

CONCLUSIONS

There is a relatively high risk of inadequate estrogen suppression in patients who switch from tamoxifen treatment to AIs. The use of sensitive and specific assays, such as LC-MS/MS methods, to monitor estrogen levels during AI treatment is essential to minimize the risk of a proceeding inefficient endocrine therapy.

Simultaneous analysis of E1 and E2 by LC-MS/MS in healthy volunteers: estimation of reference intervals and comparison with a conventional E2 immunoassay

Monitoring estrogen levels, especially estradiol (E2), is amongst others important for determining menopausal status and guidance of breast cancer treatment. We validated a serum E2 and estrone (E1) liquid chromatography tandem-mass spectrometry assay (LC-MS/MS) suitable for quantitation in human subjects. In addition, we compared our method with an E2 immunoassay (IA) and established preliminary reference values. Validation parameters were within the predetermined acceptance criteria. Assay linearity ranges were 4-1500 pmol/L for E1 and 4-2500 pmol/L for E2. Imprecision ranged from 7.4 to 9.6%. The lower limit of quantitation for E2 (8.0 pmol/L) was 11.4 times lower than the IA. The method comparison revealed differences in E2 quantitation up to 155% between both methods. The method allowed quantitation of E1 in all healthy volunteers, while E2 could not be detected in 95% versus 40% of the post-menopausal women using IA and LC-MS/MS, respectively. Male, pre-, peri- and postmenopausal female reference values were estimated. An LC-MS/MS based method combining E1 and E2 analysis was validated with superior E2 analytical sensitivity when compared to the IA.

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.

Ovarian Function Recovery During Anastrozole in Breast Cancer Patients With Chemotherapy-Induced Ovarian Function Failure

Background

Aromatase inhibitors (AIs) are given as adjuvant therapy for hormone receptor-positive breast cancer in postmenopausal women, also to those with chemotherapy-induced ovarian function failure. The current analysis reports on endocrine data of patients with chemotherapy-induced ovarian function failure who were included in the phase III DATA study assessing different durations of adjuvant anastrozole after tamoxifen.

Methods

We identified all patients with chemotherapy-induced ovarian function failure. Women who underwent a bilateral ovariectomy or used luteinizing hormone-releasing hormone agonists before random assignment were excluded. Plasma estradiol and follicle-stimulating hormone levels were monitored until 30 months after random assignment at local laboratories. We aimed to determine the ovarian function recovery (OFR) rate during AI use by the cumulative incidence competing risk method and analyzed the trend of estradiol levels during AI use by a nested case-control approach in which a subset of control subjects were compared with the OFR patients excluding the value at OFR diagnosis.

Results

The 329 eligible patients had a median age of 50.0 years (range = 45-57 years) at random assignment. Thirty-nine patients developed OFR, corresponding with a 30-month recovery rate of 12.4%. Of these, 11 (28.2%) were age 50 years or older at AI initiation. The estradiol level decreased statistically significantly by 37.8% (95% CI = 27.4% to 46.7%) over the initial 30 months of AI treatment in both groups. However, the estradiol levels in the women who experienced OFR remained statistically significantly higher (difference = 20.6%, 95% CI = 2.0% to 42.7%) prior to OFR diagnosis compared with those who did not experience OFR.

Conclusions

The risk of OFR during AI treatment in breast cancer patients with chemotherapy-induced ovarian function failure is relevant, even beyond 45 years. Furthermore, women experiencing OFR had statistically significant higher estradiol levels during AI treatment (before OFR) than those without, with potential consequences regarding efficacy.

Efficacy of anastrozole after tamoxifen in early breast cancer patients with chemotherapy-induced ovarian function failure

The DATA study (NCT00301457) compared 6 and 3 years of anastrozole in postmenopausal women with hormone receptor-positive early breast cancer after 2-3 years of tamoxifen. Patients with chemotherapy-induced ovarian function failure (CIOFF) were also eligible, but could be at risk of ovarian function recovery (OFR). The current analysis compared the survival of women with CIOFF with definitely postmenopausal women and examined the influence of OFR on survival. Therefore, we selected patients from the DATA study aged 45-57 years at randomization who had received (neo)adjuvant chemotherapy. They were classified by reversibility of postmenopausal status: possibly reversible in case of CIOFF (n = 395) versus definitely postmenopausal (n = 261). The former were monitored by E2 measurements for OFR. The occurrence of OFR was incorporated as a time-dependent covariate in a Cox-regression model for calculating the hazard ratio (HR). We used the landmark method to calculate residual 5-year survival rates. When comparing CIOFF women with definitely postmenopausal women, the survival was not different. Among CIOFF women with available E2 follow-up values (n = 329), experiencing OFR (n = 39) had an unfavorable impact on distant recurrence-free survival (HR 2.27 [95% confidence interval [CI] 0.98-5.25; p = 0.05] and overall survival (HR 2.61 [95% CI 1.11-6.13; p = 0.03]). After adjusting for tumor features, the HRs became 2.11 (95% CI 0.89-5.02; p = 0.09) and 2.24 (95% CI 0.92-5.45; p = 0.07), respectively. The residual 5-year rate for distant recurrence-free survival was 76.9% for women with OFR and 92.1% for women without OFR, and for 5-year overall survival 80.8% and 94.4%, respectively. Women with CIOFF receiving anastrozole may be at increased risk of disease recurrence if experiencing OFR.

Pretreatment anti-Mullerian hormone-based nomogram predicts menstruation status after chemotherapy for premenopausal women with hormone receptor-positive early breast cancer

PURPOSE

Ovarian function is important for optimizing endocrine treatment in patients with hormone receptor-positive (HR+) early breast cancer (eBC). The aim of the study was to determine whether patients' pretreatment levels of anti-Mullerian hormone (AMH) were associated with menses status after chemotherapy and to build a predictive nomogram model for amenorrhea in women with HR+ eBC.

METHODS

Between August 2013 and December 2014, 120 premenopausal patients with HR+ eBC were included retrospectively. The associations among age, prechemotherapy levels of AMH, follicle-stimulating hormone (FSH),and estradiol (E2) and the 2-year postchemotherapy menses status were analyzed. We determined the cutoff values of hormone levels by using the biostatistical tool (Cutoff Finder). A novel nomogram was established to predict the 2-year amenorrhea status based on the logistic analysis. Concordance index (C-index) was used to validate the capacity.

RESULTS

One hundred nine women (90.8%) experienced amenorrhea after chemotherapy. AMH < 0.965 ng/ml predicted amenorrhea at 2 years (AUC 0.84, sensitivity 74% and specificity 81.8%), independent of age. The predictive nomogram based on age and pretreatment AMH and FSH levels was developed to predict the probability of 2-year postchemotherapy amenorrhea with a C-index of 0.88 (95% CI 0.84-0.91).

CONCLUSIONS

In premenopausal patients with HR+ eBC, prechemotherapy AMH concentration was associated with the patient's 2-year amenorrhea status, independent of age. The nomogram model based on age and pretreatment AMH and FSH levels accurately predicted the 2-year amenorrhea status.

Curcumin for the Prevention of Epithelial-Mesenchymal Transition in Endoxifen-Treated MCF-7 Breast Cancer Cel

Background: Curcumin was shown to reduce epithelial-mesenchymal transition (EMT) markers in previous short term studies. This study was aimed to investigate the potential of curcumin in the prevention of EMT activation in MCF-7 cells induced by endoxifen. Methods: MCF-7 breast cancer cells were treated with Endoxifen 1000 nM+betaestradiol 1 nM with or without curcumin (8.5μM or 17 μM). Cells treated with dimethyl sulfoxide (DMSO) 0.001% were used as negative control. After 8 weeks of continuous treatment, the cells were counted, analyzed for mRNA E-cadherin, vimentin, TGF-β expression, total reactive oxygen species (ROS) and observed for morphological changes using confocal microscope and transmission electron microscope. Result: MCF-7 cell viability was increased in endoxifen + β-estradiol group. Cell viability was significantly decreased in curcumin 17 μM, but not in curcumin 8.5 μM group. Analysis of EMT markers at week 8 indicates that there were increase in vimentin and TGF-β mRNA expressions, while E-cadherin mRNA expressions and TGF-β1 protein concentrations were shown to decrease. The results showed that administration of curcumin in all the dose administered were incapable improving the expressions of vimentin, TGF-β1 and E-cadherin. There was a decrease in ROS concentration in curcumin treated cells (8.5 μM) while in curcumin 17 μM, ROS concentration was increased. Morphological observation using confocal microscope and TEM showed the presence of mesenchymal cells and adherens junction. Conclusion: endoxifen treatments for eight weeks resulted in upregulation of EMT markers and changes in morphology of MCF-7 breast cancer cells. The addition of curcumin did not prevent the activation of EMT.

Mammographic density: a potential monitoring biomarker for adjuvant and preventative breast cancer endocrine therapies

Increased mammographic density (MD) has been shown beyond doubt to be a marker for increased breast cancer risk, though the underpinning pathobiology is yet to be fully elucidated. Estrogenic activity exerts a strong influence over MD, which consequently has been observed to change predictably in response to tamoxifen anti-estrogen therapy, although results for other selective estrogen receptor modulators and aromatase inhibitors are less consistent. In both primary and secondary prevention settings, tamoxifen-associated MD changes correlate with successful modulation of risk or outcome, particularly among pre-menopausal women; an observation that supports the potential use of MD change as a surrogate marker where short-term MD changes reflect longer-term anti-estrogen efficacy. Here we summarize endocrine therapy-induced MD changes and attendant outcomes and discuss both the need for outcome surrogates in such therapy, as well as make a case for MD as such a monitoring marker. We then discuss the process and steps required to validate and introduce MD into practice as a predictor or surrogate for endocrine therapy efficacy in preventive and adjuvant breast cancer treatment settings.

The correlation of age with chemotherapy-induced ovarian function failure in breast cancer patients

PURPOSE

To assess the incidence of chemotherapy-induced ovarian function failure (COFF) based on estradiol and follicle stimulating hormone (FSH) monitoring in premenopausal women with hormone-receptor positive breast cancer treated with second and third generation (neo-)adjuvant chemotherapy.

RESULTS

We identified 115 eligible women. Two years after start of chemotherapy, COFF was significantly more often present in women ≥ 40 years (85.6%) as compared to women < 40 years (8.7%). Only age was significantly associated with COFF two years after start of chemotherapy (HR 12.26; 95% CI 5.21-28.86). In 50% of the patients, premenopausal hormone levels were the first or only evidence of ovarian function recovery (OFR).

MATERIALS AND METHODS

We included all premenopausal women with hormone-receptor positive breast cancer treated with anthracycline-based chemotherapy, with or without taxanes, in our university hospital in the Netherlands in the years 2005-2013. Patients were 3-monthly monitored for ovarian function. Cox proportional hazards model was used to determine the predictive impact of various parameters on the occurrence of COFF.

CONCLUSIONS

After second- or third generation (neo-)adjuvant chemotherapy, COFF was still present in 8.7% of patients < 40 years after two years. FSH and estradiol monitoring may be relevant for those in whom ovarian function suppression is considered an additional effective endocrine treatment.

Effects of exemestane and letrozole therapy on plasma concentrations of estrogens in a randomized trial of postmenopausal women with breast cancer

PURPOSE

Inter-individual differences in estrogen concentrations during treatment with aromatase inhibitors (AIs) may contribute to therapeutic response and toxicity. The aim of this study was to determine plasma concentrations of estradiol (E2), estrone (E1), and estrone sulfate (E1S) in a large cohort of AI-treated breast cancer patients.

METHODS

In a randomized, multicenter trial of postmenopausal women with early-stage breast cancer starting treatment with letrozole (n = 241) or exemestane (n = 228), plasma estrogen concentrations at baseline and after 3 months were quantitated using a sensitive mass spectrometry-based assay. Concentrations and suppression below the lower limit of quantification (LLOQ) were compared between estrogens and between drugs.

RESULTS

The ranges of baseline estrogen concentrations were

CONCLUSIONS

Letrozole had greater suppression of plasma E1 and E1S than exemestane, though the response was highly variable among patients. Additional research is required to examine the clinical relevance of differential estrogen suppression.

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Key Words

• Breast cancer
• Estradiol
• Estrone
• Estrone sulfate
• Exemestane
• Letrozole

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MESH Headings

• Androstadienes/administration & dosage
• Antineoplastic Combined Chemotherapy Protocols/adverse effects
• Antineoplastic Combined Chemotherapy Protocols/therapeutic use
• Breast Neoplasms/blood
• Breast Neoplasms/diagnosis
• Breast Neoplasms/drug therapy
• Estrogens/blood
• Female
• Humans
• Letrozole
• Nitriles/administration & dosage
• Postmenopause
• Treatment Outcome
• Triazoles/administration & dosage

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Grants

• T32 GM008425 NIGMS NIH HHS
• M01 RR000750 NCRR NIH HHS
• M01 RR000052 NCRR NIH HHS
• U01 GM061373 NIGMS NIH HHS
• M01 RR000042 NCRR NIH HHS

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Affiliation(s)

Jason D Robarge Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
Zereunesay Desta Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
Anne T Nguyen Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
Lang Li Center for Computational Biology and Bioinformatics, Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
Daniel Hertz Breast Oncology Program, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
James M Rae Breast Oncology Program, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
Daniel F Hayes Breast Oncology Program, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
Anna M Storniolo Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN, USA
Vered Stearns Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD, USA
David A Flockhart Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
Todd C Skaar Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
N Lynn Henry Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope Dr #3362, Salt Lake City, UT, 84112, USA.

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Collaborators Collapse

Increased vimentin mRNA expression in MCF-7 breast cancer cell line after repeated endoxifen-treatment

Background: Epithelial mesenchymal transition (EMT) plays a significant role in the development of cancer cell resistance to drugs. Vimentin, a type III intermediate filament protein, is a marker of EMT. Vimentin's over-expression in cancer correlates well with increased tumor growth, change in cell shape and poor prognosis. Endoxifen is an active metabolite of tamoxifen  and has become a new potent agent in the treatment of breast cancer. This is a study that aimed to investigate the effect of endoxifen exposure with or without estradiol on cell viability, cell morphology and EMT progression through the analysis of vimentin mRNA expression after 4-week treatment. Methods: Endoxifen, 100 nM or 1,000 nM, with or without beta-estradiol were given repeatedly to MCF-7 cells. Cells treated with dimethyl sulfoxide (DMSO) 0.001% were used as control. After 2- and 4-week exposure, the cells were counted, analyzed for mRNA vimentin expression, and observed for morphological changes. Results: Compared to control, there were significant decreases in vimentin mRNA expressions in endoxifen and endoxifen+β-estradiol treated cells after 2-weeks, which then significantly increased after 4-week compared with the 2-week exposure. We found no change in morphology of MCF-7 cells. Conclusion: Repeated exposure of endoxifen might induce EMT progression through increased expression of vimentin in MCF-7 breast cancer cell line.

Systemic Levels of Estrogens and PGE2 Synthesis in Relation to Postmenopausal Breast Cancer Risk

Background: Prostaglandin E₂ (PGE₂) induces aromatase expression in adipose tissue, leading to increased estrogen production that may promote the development and progression of breast cancer. However, few studies have simultaneously investigated systemic levels of PGE₂ and estrogen in relation to postmenopausal breast cancer risk.Methods: Here, we determined urinary estrogen metabolites (EM) using mass spectrometry in a case-cohort study (295 incident breast cancer cases and 294 subcohort members), and using linear regression estimated the effect of urinary levels of a major PGE₂ metabolite (PGE-M) on EMs. HRs for the risk of developing breast cancer in relation to PGE-M and EMs were compared between Cox regression models with and without mutual adjustment.Results: PGE-M was a significant predictor of estrone (E1), but not estradiol (E2) levels in multivariable analysis. Elevated E2 levels were associated with an increased risk of developing breast cancer [HR_Q5vs.Q1, 1.54; 95% confidence interval (CI), 1.01-2.35], and this association remained unchanged after adjustment for PGE-M (HR_Q5vs.Q1, 1.52; 95% CI, 0.99-2.33). Similarly, elevated levels of PGE-M were associated with increased risk of developing breast cancer (HR_Q4vs.Q1, 2.01; 95% CI, 1.01-4.29), and this association was only nominally changed after consideration of E1 or E2 levels.Conclusions: Urinary levels of PGE-M and estrogens were independently associated with future risk of developing breast cancer among these postmenopausal women.Impact: Increased breast cancer risk associated with PGE-M might not be fully explained by the estrogens-breast cancer association alone but also by additional effects related to inflammation. Cancer Epidemiol Biomarkers Prev; 26(3); 383-8. ©2016 AACR.

Modeling estrogen receptor-positive breast cancers in mice: is it the best we can do?

The continuous supplementation of mice with supraphysiological doses of estrogen 
for the growth of estrogen receptor-positive breast cancers has been linked to toxicity in the host and perturbation of cancer cells' function that can misguide preclinical studies. Thus, alternative experimental models with circulating levels of estrogens higher than those of mice may represent more suitable hosts to model estrogen receptor-positive breast cancers.

Falsely elevated serum oestradiol due to exemestane therapy

In this study, we present a case of falsely elevated oestradiol (E₂) concentration, determined by two immunoassays, in a breast cancer patient receiving exemestane therapy. The positive bias of immunochemical measurements was revealed using liquid chromatography tandem mass spectrometry which showed undetectable E₂ concentration. The discrepancy is expected to be a consequence of the structural resemblance of E₂ and exemestane sharing the same steroidal backbone. Inaccurate laboratory findings in therapy monitoring, as in this case, may lead to unnecessary changes of therapy.

Five furofuranone lignan glucosides from Terminalia citrina inhibit in vitro E2-enhanced breast cancer cell proliferation

Five new polyalkoxylated furofuranone lignan glucosides, terminalosides L-P (1-5), were isolated from EtOAc extracts of the leaves of Terminalia citrina, a Bangladeshi medicinal plant. The structures of the isolates were deduced primarily by NMR spectroscopy, and four of the isolates were found to contain rare tetraoxygenated aryl groups in their structures. The absolute configurations and conformations of the furofuranone ring were confirmed by ECD spectroscopy. All of the isolates were evaluated for their estrogenic and/or antiestrogenic properties using two estrogen responsive breast cancer cell lines, T47D and MCF-7. At a concentration of 10nM, terminaloside L (1) suppressed E2-enhanced T47D cell proliferation by 90%, while terminaloside M (2) showed 90% antiestrogenic activity against MCF-7 cells. Compared to 2, the antiestrogenic activity of terminaloside O (4) and P (5) was weak, possibly due to the different attachment positions of the sugar moiety that they share in common. This is the first report of furofuranone lignans from any Terminalia species, and also of their antiestrogenic activity.

Is Estradiol Monitoring Necessary in Women Receiving Ovarian Suppression for Breast Cancer?

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors’ suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

A 36-year-old premenopausal woman had been diagnosed with stage III breast cancer. After an initial biopsy confirmed breast cancer, she underwent mastectomy and axillary node dissection for a left-sided breast cancer, measuring 7 cm. The tumor had lobular histology and was considered grade 2 of 3. Metastatic carcinoma was identified in 10 of 13 axillary nodes. Immunohistochemical studies showed that the tumor was strongly positive for estrogen and progesterone receptor expression and had a Ki-67 score of 15% (> 20% is considered high according to a Swedish quality control study and the St Gallen Expert Consensus). 1 , 2 There was no amplification of the HER2/neu gene. Staging scans were negative for metastatic disease. In the adjuvant setting, she received three cycles of anthracycline-cyclophosphamide combination chemotherapy followed by three cycles of taxane chemotherapy and then locoregional radiotherapy. After completion of chemotherapy, she developed amenorrhea. As adjuvant endocrine therapy, she began monthly goserelin administration to achieve ovarian function suppression (OFS), in combination with the aromatase inhibitor (AI) exemestane. She experienced menopausal symptoms including hot flashes, vaginal dryness, and sexual dysfunction. After two monthly treatments with goserelin and exemestane, a sensitive assay for serum estradiol was checked and returned at 16 pg/mL (61 pmol/L); postmenopausal range for sensitive assay is less than 15 pg/mL (< 50 pmol/L). The patient has now been referred to our unit to discuss further management.

Cytochrome P450 1A2 Metabolizes 17β-Estradiol to Suppress Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) occurs more frequently in men than in women. It is commonly agreed that estrogen plays important roles in suppressing HCC development, however, the underlying mechanism remains largely unknown. Since estrogen is mainly metabolized in liver and its metabolites affect cell proliferation, we sought to investigate if the liver-specific cytochrome P450 1A2 (CYP1A2) mediated the inhibitory effect of estrogen on HCC. In this study, the expression of estrogen-metabolizing enzyme CYP1A2 was determined in HCC tissues and cell lines. Cell proliferation and apoptosis were assessed in cells with or without CYP1A2 overexpression. The levels of 17β-estradiol (E2) and its metabolite 2-methoxyestradiol (2-ME) were determined. A xenograft tumor model in mice was established to confirm the findings. It was found that CYP1A2 expression was greatly repressed in HCC. E2 suppressed HCC cell proliferation and xenograft tumor development by inducing apoptosis. The inhibitory effect was significantly enhanced in cells with CYP1A2 overexpression, which effectively conversed E2 to the cytotoxic 2-ME. E2 in combination with sorafenib showed an additive effect on HCC. The anti-HCC effect of E2 was not associated with estrogen receptors ERα and ERβ as well as tumor suppressor P53 but enhanced by the approved anti-HCC drug sorafenib. In addition, HDAC inhibitors greatly induced CYP1A2 promoter activities in cancer cells, especially liver cancer cells, but not in non-tumorigenic cells. Collectively, CYP1A2 metabolizes E2 to generate the potent anti-tumor agent 2-ME in HCC. The reduction of CYP1A2 significantly disrupts this metabolic pathway, contributing the progression and growth of HCC and the gender disparity of this malignancy.

Increased risk of colorectal cancer in patients diagnosed with breast cancer in women

BACKGROUND

Epidemiological studies have shown a potential association between sex hormones and colorectal cancer. The risk of colorectal cancer in breast cancer patients who may have been exposed to increased levels of endogenous sex hormones and/or exogenous sex hormones (e.g. anti-hormonal therapy) has not been thoroughly evaluated.

METHODS

Using the National Swedish Cancer Register we established a population-based prospective cohort of breast cancer patients in women diagnosed in Sweden between 1961 and 2010. Subsequent colorectal cancers were identified from the same register. Standardized incidence ratios (SIRs) and 95% confidence intervals (95%CIs) were used to estimate the risk of colorectal cancer after a diagnosis of breast cancer. The association between breast cancer therapy and risk of colorectal cancer was evaluated in a subcohort of breast cancer patients treated in Stockholm between 1977 and 2007. Hazard ratios (HRs) and 95%CIs were estimated using Cox regression models.

RESULTS

In a cohort of 179,733 breast cancer patients in Sweden, 2571 incident cases of colorectal cancer (1008 adenocarcinomas in the proximal colon, 590 in the distal colon and 808 in the rectum) were identified during an average follow-up of 9.68 years. An increased risk of colorectal adenocarcinoma was observed in the breast cancer cohort compared with that in the general population (SIR=1.59, 95%CI: 1.53, 1.65). Adenocarcinoma in the proximal colon showed a non-significantly higher SIR (1.72, 95%CI: 1.61, 1.82) compared with the distal colon (1.46, 95%CI: 1.34, 1.58). In the subcohort of 20,171 breast cancers with available treatment data, 299 cases with colorectal cancers were identified. No treatment-dependent risk of colorectal cancer was observed among the breast cancer patients.

CONCLUSION

An increased risk of colorectal adenocarcinoma - especially in the proximal colon - was observed in the breast cancer cohort. Breast cancer treatment did not alter this risk.

Incidence and Predictive Factors for Recovery of Ovarian Function in Amenorrheic Women in Their 40s Treated With Letrozole

PURPOSE

This prospective study assessed the impact of 2 years of aromatase inhibitor (AI) therapy on the incidence of ovarian function recovery (OFR) in women age 40 to 49 with estrogen receptor-positive breast cancer who were premenopausal at diagnosis and who underwent chemotherapy-induced amenorrhea during adjuvant treatment.

PATIENTS AND METHODS

Women age 40 to 49 with estrogen receptor-positive breast cancer who had ceased menstruating with adjuvant cyclophosphamide-based chemotherapy, had postmenopausal serum estradiol (E2), and had received tamoxifen for ≥ 1 year were treated with letrozole (2.5 mg) daily for ≥ 2 years. Serum follicle-stimulating hormone (FSH) and E2 were measured at baseline and over 2 years. A general linear model was used to assess serial FSH by OFR. Logistic regression was used to assess baseline predictors and OFR.

RESULTS

The study enrolled 177 women (145 women age 45 to 49 years and 32 women age 40 to 44 years). Of 173 evaluable patients, 67 (39%; 95% CI, 31% to 46%) regained ovarian function; 11 of these patients (6%; 95% CI, 3% to 10%) resumed menses, and 56 of these patients (32%; 95% CI, 25% to 39%) developed premenopausal E2 without menses. Among AI-naïve patients, serial FSH significantly increased over time (P < .001), did not vary significantly by OFR status (P = .55), but showed mild evidence of a decrease after month 12 for those who resumed menses (P = .0989). Age less than 45 years and inhibin B were significant multivariable baseline predictors of OFR.

CONCLUSION

These results emphasize the challenge in determining definitive menopause in women with chemotherapy-induced amenorrhea. The risk of OFR during treatment with AIs in amenorrheic women in their 40s is high, and AI therapy should be avoided in these patients.

Twelve-Month Estrogen Levels in Premenopausal Women With Hormone Receptor-Positive Breast Cancer Receiving Adjuvant Triptorelin Plus Exemestane or Tamoxifen in the Suppression of Ovarian Function Trial (SOFT): The SOFT-EST Substudy

PURPOSE

To describe estradiol (E2), estrone (E1), and estrone sulfate (E1S) levels during the first year of monthly triptorelin plus exemestane or tamoxifen and to assess possible suboptimal suppression while receiving exemestane plus triptorelin.

PATIENTS AND METHODS

Premenopausal patients with early breast cancer on the Suppression of Ovarian Function Trial who selected triptorelin as the ovarian suppression method and were randomly assigned to exemestane plus triptorelin or tamoxifen plus triptorelin were enrolled until the target population of 120 patients was reached. Blood sampling time points were 0, 3, 6, 12, 18, 24, 36, and 48 months. Serum estrogens were measured with a highly sensitive and specific assay. This preplanned 12-month analysis evaluated E2, E1, E1S, follicle-stimulating hormone, and luteinizing hormone levels in all patients and the proportion of patients with E2 levels greater than 2.72 pg/mL at any time point during treatment with exemestane plus triptorelin.

RESULTS

One hundred sixteen patients (exemestane, n = 86; tamoxifen, n = 30; median age, 44 years; median E2, 51 pg/mL; 55% prior chemotherapy) started triptorelin and had one or more samples drawn. With exemestane plus triptorelin, median reductions from baseline E2, E1, and E1S levels were consistently ≥ 95%, resulting in significantly lower levels than with tamoxifen plus triptorelin at all time points. Among patients on exemestane plus triptorelin, 25%, 24%, and 17% had an E2 level greater than 2.72 pg/mL at 3, 6, and 12 months, respectively. Baseline factors related to on-treatment E2 level greater than 2.72 pg/mL were no prior chemotherapy (P = .06), higher body mass index (P = .05), and lower follicle-stimulating hormone and luteinizing hormone (each P < .01).

CONCLUSION

During the first year, most patients on exemestane plus triptorelin had E2 levels below the defined threshold of 2.72 pg/mL, consistent with levels reported in postmenopausal patients on aromatase inhibitors, but at each time point, at least 17% of patients had levels greater than the threshold.

Estradiol measurement in translational studies of breast cancer

Plasma estrogen measurement with use of radioimmunoassays has been instrumental in the development of aromatase inhibitors for endocrine therapy of postmenopausal breast cancer. However, due to low plasma estrogen concentrations in postmenopausal women, direct radioimmunoassays lack the sensitivity required. While certain laboratories have developed highly sensitive assays for research purposes revealing plasma estrogen suppression consistent with results from tracer studies, such assays are time and labor-consuming due to need for pre-analytical chromatographic purification, sample concentration and sometimes conversion of precursors to products. While novel chromatographic methods involving mass spectrometry analysis are likely to replace such radioimmunoassays in the future, so far a limited number of laboratories have developed suitable assays with a detection limit (around 1 pM) that is required for analyzing plasma estrogen levels in patients during treatment with potent aromatase inhibitors.