Endometrial cancer and venous thromboembolism in women under age 50 who take tamoxifen for prevention of breast cancer: A systematic review

Discovery of novel quinoline scaffold selective estrogen receptor degraders (SERDs) for treatment of ER positive breast cancer with enhanced antiproliferative bioactivity through immunogenic cell death (ICD) effects

Combination therapy proven to be an effective therapeutic approach for estrogen receptor (ER)-positive breast cancer. Currently, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are combined with aromatase inhibitors (AIs) or selective estrogen receptor degraders (SERDs) as first-line therapy for advanced ER-positive breast cancer. Herein, a new family of quinoline scaffold SERDs was synthesized and evaluated in MCF-7 cells. Among them, compounds 18j and 24d exhibited remarkable MCF-7 inhibition, both alone and in combination with ribociclib (CDK4/6 inhibitor), in vitro and in vivo. Meanwhile, compounds 18j and 24d effectively degraded ER and inhibited ER downstream signaling pathways. Interestingly, compounds 18j and 24d induced endoplasmic reticulum stress (ERS) and triggered immunogenic cell death (ICD) via damage-associated molecular patterns (DAMPs) in MCF-7 cells. These findings highlight the immune-related and enhanced antiproliferative effects of oral SERDs in ER positive breast cancer treatment.

Reassessing the Benefits and Harms of Risk-Reducing Medication Considering the Persistent Risk of Breast Cancer Mortality in Estrogen Receptor-Positive Breast Cancer

PURPOSE

Recent studies, including a meta-analysis of 88 trials, have shown higher than expected rates of recurrence and death in hormone receptor-positive breast cancer. These new findings suggest a need to re-evaluate the use of risk-reducing medication to avoid invasive breast cancer and breast cancer death in high-risk women.

METHODS

We adapted an established Cancer Intervention and Surveillance Modeling Network model to evaluate the lifetime benefits and harms of risk-reducing medication in women with a ≥ 3% 5-year risk of developing breast cancer according to the Breast Cancer Surveillance Consortium risk calculator. Model input parameters were derived from meta-analyses, clinical trials, and large observational data. We evaluated the effects of 5 years of risk-reducing medication (tamoxifen/aromatase inhibitors) with annual screening mammography ± magnetic resonance imaging (MRI) compared with no screening, MRI, or risk-reducing medication. The modeled outcomes included invasive breast cancer, breast cancer death, side effects, false positives, and overdiagnosis. We conducted subgroup analyses for individual risk factors such as age, family history, and prior biopsy.

RESULTS

Risk-reducing tamoxifen with annual screening (± MRI) decreased the risk of invasive breast cancer by 40% and breast cancer death by 57%, compared with no tamoxifen or screening. This is equivalent to an absolute reduction of 95 invasive breast cancers, and 42 breast cancer deaths per 1,000 high-risk women. However, these drugs are associated with side effects. For example, tamoxifen could increase the number of endometrial cancers up to 11 per 1,000 high-risk women. Benefits and harms varied by individual characteristics.

CONCLUSION

The addition of risk-reducing medication to screening could further decrease the risk of breast cancer death. Clinical guidelines for high-risk women should consider integrating shared decision making for risk-reducing medication and screening on the basis of individual risk factors.

Effectiveness of Secondary Risk-Reducing Strategies in Patients With Unilateral Breast Cancer With Pathogenic Variants of BRCA1 and BRCA2 Subjected to Breast-Conserving Surgery: Evidence-Based Simulation Study

BACKGROUND

Approximately 62% of patients with breast cancer with a pathogenic variant (BRCA1 or BRCA2) undergo primary breast-conserving therapy.

OBJECTIVE

The study aims to develop a personalized risk management decision support tool for carriers of a pathogenic variant (BRCA1 or BRCA2) who underwent breast-conserving therapy for unilateral early-stage breast cancer.

METHODS

We developed a Bayesian network model of a hypothetical cohort of carriers of BRCA1 or BRCA2 diagnosed with stage I/II unilateral breast cancer and treated with breast-conserving treatment who underwent subsequent second primary cancer risk-reducing strategies. Using event dependencies structured according to expert knowledge and conditional probabilities obtained from published evidence, we predicted the 40-year overall survival rate of different risk-reducing strategies for 144 cohorts of women defined by the type of pathogenic variants (BRCA1 or BRCA2), age at primary breast cancer diagnosis, breast cancer subtype, stage of primary breast cancer, and presence or absence of adjuvant chemotherapy.

RESULTS

Absence of adjuvant chemotherapy was the most powerful factor that was linked to a dramatic decline in survival. There was a negligible decline in the mortality in patients with triple-negative breast cancer, who received no chemotherapy and underwent any secondary risk-reducing strategy, compared with surveillance. The potential survival benefit from any risk-reducing strategy was more modest in patients with triple-negative breast cancer who received chemotherapy compared with patients with luminal breast cancer. However, most patients with triple-negative breast cancer in stage I benefited from bilateral risk-reducing mastectomy and risk-reducing salpingo-oophorectomy or just risk-reducing salpingo-oophorectomy. Most patients with luminal stage I/II unilateral breast cancer benefited from bilateral risk-reducing mastectomy and risk-reducing salpingo-oophorectomy. The impact of risk-reducing salpingo-oophorectomy in patients with luminal breast cancer in stage I/II increased with age. Most older patients with the BRCA1 and BRCA2 pathogenic variants in exons 12-24/25 with luminal breast cancer may gain a similar survival benefit from other risk-reducing strategies or surveillance.

CONCLUSIONS

Our study showed that it is mandatory to consider the complex interplay between the types of BRCA1 and BRCA2 pathogenic variants, age at primary breast cancer diagnosis, breast cancer subtype and stage, and received systemic treatment. As no prospective study results are available at the moment, our simulation model, which will integrate a decision support system in the near future, could facilitate the conversation between the health care provider and patient and help to weigh all the options for risk-reducing strategies leading to a more balanced decision.

Biochemical Basis of Selective Accumulation and Targeted Delivery of Photosensitizers to Tumor Tissues

The method of photodynamic therapy for treatment of malignant neoplasms is based on the selective of accumulation of photosensitizers in the tumor tissue. Insufficient selectivity of photosensitizers in relation to pathologically altered tissues and generalized distribution throughout the body leads to the development of severe toxic effects, including skin phototoxicity. The mechanisms underlying selectivity of photosensitizers for tumor tissue include selective binding to blood proteins and lipoproteins (considering that the number of receptors for those is increased on tumor cell membranes), uptake by macrophages, better solubility at low pH (acidic pH is characteristic of tumor cells), and other mechanisms. At present, increase in the efficiency of photodynamic therapy is largely associated with the additional targeting of photosensitizers to tumor tissues. Targeted delivery strategies are based on the differences in metabolism and gene expression profiles between the tumor and healthy cells. There are differences in expression of receptors, proteases, or transmembrane transporters in these cells. In particular, accelerated metabolism in many types of tumors leads to overexpression of receptors for epidermal growth factor, folic acid, transferrin, and a number of other compounds. This review considers biochemical basis for the selective accumulation of various classes of photosensitizers in tumors (chlorins, phthalocyanines, 5-aminolevulinic acid derivatives, etc.) and discusses various strategies of targeted delivery with emphasis on conjugation of photosensitizers with the receptor ligands overexpressed in tumor cells.

Risk of Endometrial Polyps, Hyperplasia, Carcinoma, and Uterine Cancer After Tamoxifen Treatment in Premenopausal Women With Breast Cancer

IMPORTANCE

The association of tamoxifen use with the risk of uterine diseases, such as endometrial cancer, in premenopausal women with breast cancer remains controversial. However, many studies have reported an increased risk of uterine disease among postmenopausal tamoxifen users.

OBJECTIVE

To investigate the association of tamoxifen use with the risk of endometrial cancer and other uterine diseases in premenopausal women with breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide, population-based, retrospective longitudinal cohort study with an 18-year study period was conducted using data obtained from the Korean National Health Insurance Service. Participants included premenopausal women aged 20 to 50 years with breast cancer diagnoses between January 2003 and December 2018. Data were analyzed from April to December 2021.

EXPOSURES

Tamoxifen treatment.

MAIN OUTCOMES AND MEASURES

The incidence of uterine diseases, including endometrial cancer, hyperplasia, polyps, and other uterine cancers, was identified in the study cohort using insurance claim codes. The incidence of uterine diseases per 1000 person-years was compared between women receiving tamoxifen and those not treated with adjuvant hormone therapy. Multivariable Cox proportional hazard regression analysis was performed to determine the risk of each uterine disease.

RESULTS

Among 78 320 female participants with a mean (SD) age of 42.1 (6.1) years, 34 637 (44.2%) were categorized into the tamoxifen group and 43 683 (55.8%) were categorized into the control group. Among tamoxifen users, during the mean (SD) follow-up duration of 6.13 (4.15) years, the incidence of newly diagnosed endometrial polyps was 20.13 cases per 1000 person-years, that of endometrial hyperplasia was 13.49 cases per 1000 person-years, that of endometrial cancer was 2.01 cases per 1000 person-years, and that of other uterine cancers was 0.45 cases per 1000 person-years. The risk of endometrial cancer was higher in the tamoxifen group than in the control group (hazard ratio, 3.77; 95% CI, 3.04-4.66) after adjusting for age, body mass index, history of diabetes, hypertension, dyslipidemia, polycystic ovary syndrome, gonadotropin-releasing hormone agonist treatment, and trastuzumab treatment.

CONCLUSIONS AND RELEVANCE

In this longitudinal cohort study, premenopausal Korean women with breast cancer who received tamoxifen as adjuvant hormone therapy had a significantly increased risk of endometrial hyperplasia, polyps, carcinoma, and other uterine cancers compared with those who were not treated with adjuvant hormone therapy. These findings suggest that clinicians should consider the risk of uterine disease among tamoxifen users, including premenopausal women.

Extended adjuvant endocrine treatment for premenopausal women: A Delphi approach to guide clinical practice

The use of an aromatase inhibitor (AI) in combination with ovarian function suppression (OFS) has become the mainstay of adjuvant endocrine therapy in high-risk premenopausal patients with hormone receptor-positive breast cancer. Although five years of such therapy effectively reduces recurrence rates, a substantial risk of late recurrence remains in this setting. Multiple trials have shown that extending AI treatment beyond five years could offer further protection. However, as these studies comprised only postmenopausal patients, no direct evidence currently exists to inform about the potential benefits and/or side effects of extended AI + OFS therapies in premenopausal women. Given these grey areas, we conducted a Delphi survey to report on the opinion of experts in breast cancer treatment and summarize a consensus on the discussed topics. A total of 44 items were identified, all centred around two main themes: 1) defining reliable prognostic factors to pinpoint premenopausal patients eligible for endocrine therapy extension; 2) designing how such therapy should optimally be administered in terms of treatment combinations and duration based on patients' menopausal status. Each item was separately discussed and anonymously voted by 12 experts representing oncological institutes spread across Italy. The consensus threshold was reached in 36 out of 44 items (82%). Herein, we discuss the levels of agreement/disagreement achieved by each item in relation to the current body of literature. In the absence of randomized trials to guide the tailoring of extended AI treatment in premenopausal women, conclusions from our study provide a framework to assist routine clinical practice.

BRCA1 and Metastasis: Outcome of Defective DNA Repair

Simple Summary

BRCA1 has critical functions in accurately repairing double stand breaks in the DNA through a process known as homologous recombination. BRCA1 also has various functions in other cellular processes that safeguard the genome. Thus, mutations or silencing of this tumor suppressor significantly increases the risk of developing breast, ovarian, and other cancers. Metastasis refers to the spread of cancer to other parts of the body and is the leading cause of cancer-related deaths. In this review, we discuss the mechanisms by which BRCA1 mutations contribute to the metastatic and aggressive nature of the tumor cells.

Abstract

Heritable mutations in BRCA1 and BRCA2 genes are a major risk factor for breast and ovarian cancer. Inherited mutations in BRCA1 increase the risk of developing breast cancers by up to 72% and ovarian cancers by up to 69%, when compared to individuals with wild-type BRCA1. BRCA1 and BRCA2 (BRCA1/2) are both important for homologous recombination-mediated DNA repair. The link between BRCA1/2 mutations and high susceptibility to breast cancer is well established. However, the potential impact of BRCA1 mutation on the individual cell populations within a tumor microenvironment, and its relation to increased aggressiveness of cancer is not well understood. The objective of this review is to provide significant insights into the mechanisms by which BRCA1 mutations contribute to the metastatic and aggressive nature of the tumor cells.

Endometrial Surveillance in Tamoxifen and Letrozole Treated Breast Cancer Patients

Background: Our study aimed to assess the risk of endometrial pathologies after tamoxifen and aromatase inhibitors (AIs) adjuvant treatment for female breast cancer patients treated at Sultan Qaboos University Hospital in Oman.

Materials and Methods: A total of 457 patients diagnosed with estrogen positive breast cancer between January 2011 and December 2018 were screened. Two hundred and four patients met the inclusion criteria, and their detailed clinicopathological and endometrial surveillance data were collected from their electronic health records.

Results: All patients underwent endometrial assessment during tamoxifen or letrozole therapy. The mean diagnostic age of breast cancer patients is 43.6 years, ranging from 27-84 years. Eighty-three percent of those patients are premenopausal, and 17% are postmenopausal. The mean tamoxifen use duration was 33 months. The majority of patients, 123 (60.3%), have had tamoxifen for three years or less, 47 (23.1%) for 3-5 years, and only 22 (10.8%) were on tamoxifen for more than five years. Increased endometrial thickness was reported in 8% of the premenopausal and 14% of the postmenopausal group. Other endometrial pathologies that were detected are inactive endometrium three (1.47%), atrophic endometrium three (1.47%), serous carcinoma one (0.50%), endometrial cancer two (0.98%), and chronic endometritis one (0.50%), which were not significantly associated with tamoxifen or letrozole therapy duration. Two patients have developed endometrial cancer, and both are postmenopausal and > 60 years old.

Conclusions: Tamoxifen and letrozole did not increase the risk of endometrial cancer in premenopausal patients. Breast Cancer (BC) patients on tamoxifen or letrozole might need a pre-treatment endometrial evaluation and explanation of alarming symptoms to guide further endometrial surveillance.

Optimal Endocrine Therapy in Premenopausal Women: A Pragmatic Approach to Unanswered Questions

Recent epidemiologic data show an increasing incidence of breast cancer among premenopausal women in many higher-income countries. Among premenopausal women, those diagnosed under age 40 years experience inferior long-term outcomes, particularly in the setting of hormone receptor-positive, human epidermal growth factor receptor 2-negative disease. In addition to more advanced disease presentation and/or less favorable disease biology, suboptimal adjuvant endocrine therapy (ET) has emerged as an important driver of this age-related disparity. Historically, young women have been excluded from treatment with aromatase inhibitors (AIs), attained low rates of chemotherapy-related amenorrhea, and exhibited low adherence to ET. Recently, several studies have demonstrated treatment with ovarian function suppression (OFS) during the first 5 years postdiagnosis to be associated with improvements in breast cancer recurrence and mortality, with additional benefits achieved from pairing OFS with an AI. As the first 5 years of ET for premenopausal women has been transformed, extended ET, administered in years 5-10 postdiagnosis, has also become more common. However, the only studies of extending ET in premenopausal women have tested an additional 5 years of tamoxifen following an initial 5 years of tamoxifen and studies of AIs in the second 5 years have been limited to postmenopausal women. Herein, we review available data concerning potential benefits and risks to be considered when counseling premenopausal women on extended ET, including the continuation of OFS. We offer a pragmatic framework to support decision making given the current body of knowledge and call out the need for additional research into this issue.

FLTX2: A Novel Tamoxifen Derivative Endowed with Antiestrogenic, Fluorescent, and Photosensitizer Properties

Tamoxifen is the most widely used selective modulator of estrogen receptors (SERM) and the first strategy as coadjuvant therapy for the treatment of estrogen-receptor (ER) positive breast cancer worldwide. In spite of such success, tamoxifen is not devoid of undesirable effects, the most life-threatening reported so far affecting uterine tissues. Indeed, tamoxifen treatment is discouraged in women under risk of uterine cancers. Recent molecular design efforts have endeavoured the development of tamoxifen derivatives with antiestrogen properties but lacking agonistic uterine tropism. One of this is FLTX2, formed by the covalent binding of tamoxifen as ER binding core, 7-nitrobenzofurazan (NBD) as the florescent dye, and Rose Bengal (RB) as source for reactive oxygen species. Our analyses demonstrate (1) FLTX2 is endowed with similar antiestrogen potency as tamoxifen and its predecessor FLTX1, (2) shows a strong absorption in the blue spectral range, associated to the NBD moiety, which efficiently transfers the excitation energy to RB through intramolecular FRET mechanism, (3) generates superoxide anions in a concentration- and irradiation time-dependent process, and (4) Induces concentration- and time-dependent MCF7 apoptotic cell death. These properties make FLTX2 a very promising candidate to lead a novel generation of SERMs with the endogenous capacity to promote breast tumour cell death in situ by photosensitization.

Synthesis of Triphenylethylene-Naphthalimide Conjugates as topoisomerase-IIα inhibitor and HSA binder

A series of triphenylethylene-naphthalimide (TPE-naph) conjugates was synthesized by a molecular hybridization technique, and their anticancer activity was evaluated in vitro on 60 human cancer cell lines through their cytotoxicity. The ratios of E and Z isomers were determined on the basis of HPLC methodology and NMR spectroscopy. The structure-activity relationship for anticancer activity was deduced on the basis of the nature and bulkiness of the amine attached to the C-4 position of the naphthalene ring. Experimental and molecular modeling studies of the most active TPE-naph conjugate bearing a morpholinyl group showed that it was able to inhibit topoisomerase-II (TOPO-II) as a possible intracellular target. Moreover, the transportation behavior of TPE-naph conjugate towards human serum albumin (HSA) indicated efficient binding affinity. The steady-state and time-dependent fluorescent results suggested that this conjugate quenched HSA significantly through static as well as dynamic quenching. Thus, this report discloses the scope of triphenylethylene-naphthalimide (TPE-naph) conjugates as efficient anticancer agents.

Tamoxifen attenuates renal fibrosis in human kidney slices and rats subjected to unilateral ureteral obstruction

BACKGROUND AND PURPOSE

Renal fibrosis plays an important role in the development and progression of chronic kidney disease (CKD). Clinical studies have shown that CKD progresses differently in males and females, which may be related to circulating levels of sex hormones. In this study, we investigated the effect of tamoxifen (TAM), a selective estrogen receptor modulator (SERM), on renal fibrosis in male and female rats subjected to unilateral ureteral obstruction (UUO) and human precision-cut kidney slices (PCKS).

EXPERIMENTAL APPROACH

Female, ovariectomized female (OVX), and male rats were subjected to 7 days of UUO and treated with TAM by oral gavage. Moreover, we studied individual responses to TAM treatment in PCKS prepared from female and male patients. In all models, the expression of fibrosis markers was examined by western blot, qPCR, and immunohistochemistry.

KEY RESULTS

TAM decreased the expression of fibronectin, α-smooth muscle actin, and collagen-1 and -3 in female, OVX, and male rats. In addition, TAM mitigated TGF-β-induced fibrosis in human PCKS, irrespective of sex, yet interindividual differences in treatment response were observed.

CONCLUSION AND IMPLICATIONS

TAM ameliorates renal fibrosis in males and females, although we did observe sex differences in drug response. These findings warrant further research into the clinical applicability of TAM, or other SERMs, for the personalized treatment of renal disease.

Value of endometrial thickness in diagnosis of endometrial hyperplasia during selective estrogen receptor modulator therapy in premenopausal breast cancer patients

OBJECTIVE

The weak estrogenic-like effect of selective estrogen receptor modulator (SERM) may lead to series of endometrial lesions, including proliferation, hyperplasia, polyp formation, and even endometrial cancer. This study aimed to explore the effectiveness of different endometrial thickness in diagnosis of endometrial hyperplasia during SERM therapy in premenopausal patients.

METHODS

The clinical data of 115 patients receiving hysteroscopic endometrial biopsy during SERM therapy in Peking Union Medical College Hospital, China from January 2010 to December 2018 were retrospectively analyzed.

RESULTS

Average age at the beginning of SERM therapy was 43.4 ± 5.7 years old. Mean duration time of SERM therapy was 31.0 ± 22.1 months. The mean endometrial thickness was 14.3 ± 6.1 mm. 4 cases of atypical endometrial hyperplasia (3.5 %), and 4 cases of endometrial hyperplasia without atypia (3.5 %) were detected. Endometrial thickness was higher in endometrial hyperplasia patients than in no endometrial hyperplasia patients (18.8 vs 13.9 mm, p = 0.029). Endometrial thickness in 8 out of 8 endometrial hyperplasia patients and 38 out of 107 no endometrial hyperplasia patients were ≥ 15 mm (p = 0.002). The negative predictive value in the diagnosis of endometrial hyperplasia during SERM therapy in premenopausal patients was 100 % when endometrial thickness < 15 mm chosen as cutoff value.

CONCLUSION

Endometrial hyperplasia was less likely to occur in premenopausal patients during SERM therapy when endometrial thickness < 15 mm.

FRET mechanism between a fluorescent breast-cancer drug and photodynamic therapy sensitizers

Tamoxifen is one of the most frequently used drugs for the treatment of estrogen receptor positive breast cancer, which is the most prevalent form of hormone dependent breast cancer. A few years ago, we developed a fluorescent derivative of tamoxifen formed by the covalent binding of tamoxifen to a common dye biomarker. The new compound, known as FLTX1, showed the pharmacological activity of the tamoxifen moiety and efficient fluorescence properties, which could be used synergistically to improve the effect of the drug. In this paper, we demonstrate that irradiation at the absorption band of FLTX1 can result in fluorescence resonance energy transfer to photosensitizers such as Rose Bengal and Merocyanine 540, activating the production of reactive oxygen species (ROS). Indeed, the generation of ROS was demonstrated using a colorimetric assay. Since FLTX1 mostly binds estrogen-receptor overexpressing cancer cells, the results obtained are very promising and suggest a new therapeutic strategy combining chemo- and photodynamic therapies.

Endocrine Risk Factors of Endometrial Cancer: Polycystic Ovary Syndrome, Oral Contraceptives, Infertility, Tamoxifen

Endometrial cancer is the most common gynecologic cancer and is predominantly endocrine-related. The role of unopposed estrogen in the development of endometrial cancer has been investigated in numerous studies. Different reproductive factors such as younger age at menarche, late age at menopause, infertility, nulliparity, age of birth of the first child, and long-term use of unopposed estrogens during hormone replacement therapy have been associated with an increased risk of endometrial cancer. In contrast, there is a growing body of evidence for a protective role of oral contraceptives. Most of the published data on the association between infertility and polycystic ovary syndrome are inconclusive, whereas the effect of tamoxifen on the risk of endometrial cancer has been well established. With this review, we aim to summarize the evidence on the association between infertility, polycystic ovary syndrome, oral contraceptives, and tamoxifen and the development of endometrial cancer.

Risk Factors Associated with Endometrial Pathology in Premenopausal Breast Cancer Patients Treated with Tamoxifen

PURPOSE

To evaluate factors associated with endometrial pathology during tamoxifen use in premenopausal breast cancer (BC) patients.

MATERIALS AND METHODS

We reviewed the medical records of premenopausal BC patients treated with tamoxifen who underwent endometrial biopsy with or without hysteroscopy. Clinical characteristics were compared between women with endometrial pathology (endometrial hyperplasia or cancer) and those with normal histology or endometrial polyps.

RESULTS

Among 284 endometrial biopsies, endometrial hyperplasia was diagnosed in 7 patients (2.5%), endometrial cancer was diagnosed in 5 patients (1.8%), normal histology was noted in 146 patients (51.4%), and endometrial polyp was present in 114 patients (40.1%). When comparing women with endometrial cancer (n=5) to women with normal histology, abnormal uterine bleeding was more common (p=0.007), and endometrial thickness was greater (p=0.007) in women with endometrial cancer. Chemotherapy for BC was also more common in patients with endometrial cancer (p=0.037). When comparing women with endometrial polyps and those with endometrial hyperplasia or cancer, the presence of abnormal uterine bleeding was more common in patients with endometrial hyperplasia or cancer (p<0.001); however, tamoxifen duration and endometrial thickness did not differ significantly between the two groups.

CONCLUSION

In premenopausal BC patients treated with tamoxifen, abnormal uterine bleeding, increased endometrial thickness, and chemotherapy for BC were associated with the occurrence of endometrial cancer. These findings may provide useful information for gynecologic surveillance and counseling during tamoxifen treatment in premenopausal BC patients.

The relationship between KRAS LCS6 polymorphism and endometrium cancer

The aim of this study was to investigate the relationship between KRAS LCS6 mutation and endometrial cancer (EC). The study included 105 patients who had hysterectomy for benign reasons and 99 EC patients. The patients with Type 1 EC were classified according to histological properties, cancer stage, grade, tumour dimension, myometrial invasion (MMI), lymphovascular invasion (LVI), cytology, and number of positive lymph nodes. KRAS LCS6 mutation was examined in blood samples taken from all patients in both groups. No statistically significant difference was determined between the EC patients and the control group in demographic features. Weight and the Body Mass Index (BMI) values were higher in EC group (p < .001). While the incidence of this polymorphism is 5.8% throughout the world, the polymorphism rate was found to be 16.2% in the EC group and 12.4% in the control group, with no statistically significant difference determined (p > .05). Despite the higher rate of LCS6 polymorphism incidence in EC patients in this study conducted on a relatively large sample, there was not found to be a statistically significant difference in comparison with the control group. In addition, the presence of LCS6 polymorphism was not determined to have an effect on EC histopathological characteristics.Impact statementWhat is already known on this subject? Endometrial cancer (EC) is a genital system cancer which is one of the most widespread gynecological cancers seen in the USA and other developed countries, In EC, the most frequently seen gene mutations are PTEN tumour suppressor gene, KRAS, β1 catenin, BCL-2, CTNNB and P53 mutations. KRAS LCS6(let-7 miRNA binding region polymorphism) polymorphism has a worldwide incidence of 5.8% (Chin et al. 2008).There are studies shown that KRAS LCS6 polymorphism has an effect on developing EC (Lee et al. 2014), ovarian cancer(Ratner et al. 2010)and endometriosis in women (Grechukhina et al. 2012).What do the results of this study add? In our study, LCS6 located on KRAS 3'-UTR was found at the rate of 16.2% in Type 1 EC patients. This increase is noticeable when it is considered that the incidence of this polymorphism is 5.8% in the general population. The results of the current study supports the preliminary findings of Lee et al.What are the implications of these findings for clinical practice and/or further research? These new genetic markers could help to develop gene-targeted therapies, identify genetic basis of the disease and the factors that could affect the EC prognosis.

Younger tamoxifen-treated breast cancer patients also had higher risk of endometrial cancer and the risk could be reduced by sequenced aromatase inhibitor use: A population-based study in Taiwan

Objective:

Previous Western studies reported that older (≥50 years) breast cancer survivors with tamoxifen treatment had higher risk of endometrial cancer. This study aims to disclose whether younger (<50 years) tamoxifen-treated breast cancer patients also had higher risk of endometrial cancer and to examine whether sequenced aromatase inhibitor (AI) use could reduce the risk.

Materials and Methods:

A population-based cohort of 39,216 newly diagnosed breast cancer patients was identified from Taiwan National Health Insurance Database from 1999 to 2012. The risk of endometrial cancer in nonusers (n = 14,588), tamoxifen-only (n = 19,302), and sequenced AI (n = 5326) users was compared with Cox regression analysis and was adjusted with age, diabetes, hypertension, and chemotherapy.

Results:

During the 14-year study period, 133 patients were diagnosed with subsequent endometrial cancers. Compared with nonusers, tamoxifen-only users had higher risk of endometrial cancer (14-year incidence 1.7% vs. 0.3%; adjusted hazard ratio [HR] 3.90; 95% confidence interval [CI], 2.37–6.42). This was observed in both older (≥50 years) and younger (40–50 years) age groups. Adjusted HR (95% CI) for the latter was 3.74 (1.65–8.48). This risk persisted after cessation of tamoxifen use. The risk of endometrial cancer was lower in sequenced AI when compared with tamoxifen-only users (adjusted HR 0.43; 95% CI, 0.25–0.72).

Conclusions:

Not only patients ≥50 years but also younger (40–49 years) patients with tamoxifen treatment had higher risk of subsequent endometrial cancer in this nation-wide cohort. We suggest regular gynecologic monitoring not only during active use but also during follow-up phase. Sequenced AI use may reduce the risk of endometrial cancer in tamoxifen-treated breast cancer patients.

Tamoxifen for bipolar disorder: Systematic review and meta-analysis

BACKGROUND

Tamoxifen is an oral medication that has been proposed as a potential treatment for bipolar disorder. Tamoxifen acts to inhibit the intracellular action of protein kinase C, which is also an action of well-established treatments such as lithium and valproate. Here we aimed to identify randomised controlled trials (RCTs) of tamoxifen in the treatment of bipolar disorder and synthesise their results using meta-analysis.

METHODS

RCTs were identified by searching of electronic databases and from discussion with experts in the field. Data were extracted, and meta-analyses performed in R.

RESULTS

Five placebo-controlled RCTs of tamoxifen in the treatment of acute mania were identified. There were no trials in the treatment of episodes of bipolar depression, or for relapse prevention. The studies of mania treatment were of between three and six weeks duration. Tamoxifen was studied either as monotherapy (two trials) or as augmentation of lithium or valproate (three trials). Change in mania scale scores favoured tamoxifen over placebo: SMD -2.14 (95% CI -3.39 to -0.89; 4 trials), as did endpoint mania scale scores SMD 1.23 (95% CI 0.60-1.87; 5 trials). Response rates were also higher: RR 4.35 (1.99-9.50; 4 trials). Acceptability was similar to placebo: RR 1.03 (0.94-1.13; 5 trials).

CONCLUSIONS

Tamoxifen appears to be a promising potential treatment for episodes of mania. Future studies could investigate its effects as an adjunct to dopamine antagonists for improved anti-manic efficacy, and establish its longer term effects on mood, particularly depression and relapse.

Event-free survival following early endometrial events in breast cancer patients treated with anti-hormonal therapy: A nationwide claims data study

Tamoxifen, an anti-estrogen agent that can suppress breast cancer, has been reported to increase endometrium-related adverse events. There are no guidelines for screening tamoxifen-treated patients for endometrial disease. We analyzed nationwide claims data related to endometrial diseases to investigate patterns of endometrial disease in breast cancer patients who underwent hormonal treatment.We sourced claims data from the Health Insurance Review and Assessment Service in South Korea. Patients who made their first claim for an anti-hormonal agent between January 1, 2010 and December 31, 2012 were enrolled retrospectively. We analyzed patient characteristics and all claims related to endometrial disease, stratified by prescribed hormonal agents.Among a total of 32,496 enrolled patients, 19,603 used tamoxifen only and 10,101 were treated with an aromatase inhibitor (AI) alone. Endometrial events occurred in 15.4% (3028/19603) of the tamoxifen-only patients and 2.0% (201/10101) of the AI-only group. In patients diagnosed with breast cancer at the age of 50 or older, the hazard ratio (HR) of endometrial malignancy in the tamoxifen-only group compared to the AI-only group was 4.13 (95% CI 1.404-12.159, P = .010). The HR of curettage in the tamoxifen-only group was 31.0 (95% CI 19.668-48.831, P <.001).The occurrence of endometrial events among tamoxifen-treated breast cancer patients was higher than in patients treated with only AI, similar to previous studies. However, the HR of curettage was uniquely high, despite its invasiveness. Guidelines for screening endometrial disease and improvements of healthcare policy are required to appropriately manage high-risk patients.

Case for a role of the microbiome in gynecologic cancers: Clinician's perspective

In this review, we aimed to provide insight into the microbiome and its association with endometrial and ovarian cancer and their risk factors. We reviewed the literature focusing on the relationship between the microbiome and cancer, as well as the relationship between gynecologic diseases and cancers. The human body contains different kinds of microorganisms in various body parts, which is termed the microbiome. The number of microorganisms that live in and on the human body is greater than that of the human germ and somatic cells by 10-fold. The relationship between a human and their microbiome is complex; it is also one of the most important components of homeostasis. Impairment of microbiome-host homeostasis has been associated with obesity, several cancers, preterm labor, inflammatory and allergic conditions and neurodevelopmental disorders. Direct and strong causal relationships have been established for several cancers and microorganisms, such as gastric lymphoma and Helicobacter pylori infection. Interestingly, eradication of the infectious agents has also been shown to be therapeutic. The association between cancer and the microbiome, however, is more complicated than a 1 bacteria-1 cancer model, and a shift in a healthy microbiome can result in various cancers via inflammation, change in microenvironment or DNA-damaging toxins. The human microbiome is an integral part of homeostasis. Understanding the mechanisms that cause dysbiosis will enable us to elucidate the pathways that result in malignancy and investigate new treatment modalities.

Metastatic gynecologic malignancies: advances in treatment and management

Gynecologic cancers comprise of mostly uterine, ovarian, and cervical malignancies and are responsible for 95,000 new cases annually in the United States. Uterine cancer is the most common and the number of new cases and mortality has been increasing. Cervical cancer has decreased due to screening, early detection, and treatment of pre-invasive cancers. However, ovarian cancer remains the most lethal because of advanced stage at diagnosis and drug resistance. The metastatic spread pattern differs amongst these cancers, with uterine and cervical cancer found mostly in the primary organ and ovarian cancer disseminating throughout the peritoneum and upper abdomen at presentation. The primary treatment of ovarian cancer typically involves surgery followed by systemic therapy for more advanced disease. Previously, systemic chemotherapy with platinums, taxanes, doxorubicin, topotecan, and gemcitabine has been the standard in either upfront or recurrent setting. With molecular and genetic breakthroughs, we now have over eight new indications and five novel biologic therapies including antiangiogenics, poly ADP ribose polymerase inhibitors, and immunotherapies approved over the last 3 years. In this review, we will examine the biology of gynecologic cancer metastasis and focus on new treatment options for these cancers with a focus on ovarian cancer.

Precision Prevention and Early Detection of Cancer: Fundamental Principles

Prevention and early detection is critical for reducing the population cancer burden. Two approaches have been used: Population approaches change social norms (e.g., smoking bans) or impose incentives (e.g., cigarette taxes); high-risk strategies intervene upon individuals with elevated cancer risk (e.g., smoking cessation). Knowledge about carcinogenesis mechanisms, extreme exposures, and inherited susceptibility provides opportunities to develop precision prevention and early-detection (PPED) strategies. PPED aims to understand the basis of risk, identify groups that optimally benefit from interventions, characterize heterogeneity in intervention responses, optimize intervention timing, and minimize toxicities. We propose a framework around which PPED strategies can be developed. Currently available cancer prevention and early-detection approaches have the potential to reduce a large proportion of the cancer burden in the population. However, even if fully implemented, existing methods cannot fully eliminate the cancer burden. New PPED approaches that exploit the growing knowledge of molecular and biological cancer mechanisms should be developed and implemented. Cancer Discov; 8(7); 803-11. ©2018 AACR.

Obesity, Thrombotic Risk, and Inflammation in Cancer

Neoplasms exhibits a high incidence and mortality rates due to their complex and commonly overlapping clinical, biochemical, and morphologic profiles influenced by acquired or inherited molecular abnormalities, cell of origin, and level of differentiation. Obesity appears related to ~20% of cancers including endometrial, esophageal, colorectal, postmenopausal breast, prostate, and renal. Several factors other than obesity, i.e., insulin, insulin-like growth factor, sexual hormones, and adipokines may play a potential role in neoplasia. Cancer-associated hypercoagulable and thrombotic states are influenced by abnormalities in the vascular wall and susceptibility to invasion, interference in blood flow and increase in circulating tissue factor and thrombin, activation of cell growth factors, the presence of a central catheter, chemotherapies, neoplasm type, and surgery. In cancer, thromboembolic complications are the second most frequent cause of death with pulmonary thromboembolism in ~50% of cases postmortem. Thrombosis worsens prognosis as demonstrated with a survival rate as low as 12% per year vs 36% in nonthrombic patients. Deep vein thrombosis is the most frequent thromboembolic complication in cancer. It is usually detected at diagnosis and within the first 3 months of chemotherapy. The underlining mechanisms of this association should be further studied to identify patients at higher risk and develop adequate prevention, diagnostic, and treatment measures. The D-dimer test can be successfully used to assess the fibrinolytic phase of coagulation and as such is routinely used in suspected cases of deep vein thrombosis and pulmonary thromboembolism. In addition, significant advances have been made in understanding the composition and functional capabilities of the gut microbiota in the inflammatory process, obesity, and its roles in cancer; however, the intricate balance that exists within the microbiota may not only affect the host directly, it can also disrupt the entire microbial community.

CONCLUSIONS

Cancer is a prothrombotic and inflammatory state in which the activation of coagulation is related to tumor growth, angiogenesis, and metastasis. It is important to identify the relationship between body mass index with these processes and clarify their importance in cancer prognosis. Future research should answer the question if manipulation of resident microbial communities could potentially improve prognosis and treatment outcome.

Skeletal and Uterotrophic Effects of Endoxifen in Female Rats

Endoxifen, the primary active metabolite of tamoxifen, is currently being investigated as a novel endocrine therapy for the treatment of breast cancer. Tamoxifen is a selective estrogen receptor modulator that elicits potent anti-breast cancer effects. However, long-term use of tamoxifen also induces bone loss in premenopausal women and is associated with an increased risk of endometrial cancer in postmenopausal women. For these reasons, we have used a rat model system to comprehensively characterize the impact of endoxifen on the skeleton and uterus. Our results demonstrate that endoxifen elicits beneficial effects on bone in ovary-intact rats and protects against bone loss following ovariectomy. Endoxifen is also shown to reduce bone turnover in both ovary-intact and ovariectomized rats at the cellular and biochemical levels. With regard to the uterus, endoxifen decreased uterine weight but maintained luminal epithelial cell height in ovariectomized animals. Within luminal epithelial cells, endoxifen resulted in differential effects on the expression levels of estrogen receptors α and β as well as multiple other genes previously implicated in regulating epithelial cell proliferation and hypertrophy. These studies analyze the impact of extended endoxifen exposure on both bone and uterus using a Food and Drug Administration-recommended animal model. Although endoxifen is a more potent breast cancer agent than tamoxifen, the results of the present study demonstrate that endoxifen does not induce bone loss in ovary-intact rats and that it elicits partial agonistic effects on the uterus and skeleton in ovariectomized animals.

Current strategies in the diagnosis of endometrial cancer

PURPOSE

Endometrial cancer is the most common gynecological malignancy in developed countries. There are no uniform recommendations for endometrial cancer screening in the general population. Therefore, it is of paramount importance that the primary physician profoundly understands, and is familiar with the methods for prevention and early detection of endometrial cancer. The aim of this review is to provide the primary physician with a toolbox to reach these goals.

METHODS

We performed a systemic review to summarize the current strategies to diagnose and prevent endometrial cancer. Many published articles from the last years were identified and included.

RESULTS

A systematic review that summarizes the important subjects in the diagnosis and prevention of endometrial cancer.

CONCLUSION

Maintaining a high index of suspicion and obtaining endometrial biopsies from all suspected patients is the key for achieving a timely diagnosis.

Fulvestrant reverses doxorubicin resistance in multidrug-resistant breast cell lines independent of estrogen receptor expression

Drug resistance, a major obstacle to successful cancer chemotherapy, frequently occurs in recurrent or metastatic breast cancer and results in poor clinical response. Fulvestrant is a new type of selective estrogen receptor (ER) downregulator and a promising endocrine therapy for breast cancer. In this study, we evaluated the combination treatment of fulvestrant and doxorubicin in ER-negative multidrug-resistant (MDR) breast cancer cell lines Bads-200 and Bats-72. Fulvestrant potentiated doxorubicin-induced cytotoxicity, apoptosis and G2/M arrest with upregulation of cyclin B1. It functioned as a substrate for P-glycoprotein (P-gp) without affecting its expression. Furthermore, fulvestrant not only restored the intracellular accumulation of doxorubicin but also relocalized it to the nuclei in Bats-72 and Bads-200 cells, which may be another potential mechanism of reversal of P-gp mediated doxorubicin resistance. These results indicated that the combination of fulvestrant and doxorubicin-based chemotherapy may be feasible and effective for patients with advanced breast cancer.

Colocalization of Estrogen Receptors with the Fluorescent Tamoxifen Derivative, FLTX1, Analyzed by Confocal Microscopy

Tamoxifen is a selective estrogen receptor modulator that competitively binds the ligand-binding domain of estrogen receptors. Binding of tamoxifen displaces its cognate ligand, 17β-estradiol, thereby hampering the activation of estrogen receptors. Cellular labeling of ER is typically carried out using specific antibodies which require permeabilization of cells, incubation with secondary antibodies, and are expensive and time consuming. In this article, we describe the usefulness of FLTX1, a novel fluorescent tamoxifen derivative, which allows the labeling of estrogen receptors in immunocytochemistry and immunohistochemistry studies, both under permeabilized and non-permeabilized conditions. Further, besides labeling canonical estrogen receptors, this novel fluorescent probe is also suitable for the identification of unconventional targets such membrane estrogen receptors as well as other noncanonical targets, some of which are likely responsible for the number of undesired side effects reported during long-term tamoxifen treatments.

A pooled analysis of CYP2D6 genotype in breast cancer prevention trials of low-dose tamoxifen

Decreased CYP2D6 activity is associated with lower levels of active tamoxifen metabolites. We examined the impact of CYP2D6 genotype on tamoxifen pharmacokinetics, biomarker activity, and efficacy in a pooled analysis of low-dose tamoxifen. Four randomized breast cancer prevention trials of very-low-dose (1 mg/day, n = 52 or 10 mg/week, n = 152) or low-dose tamoxifen (5 mg/day, n = 171) were pooled. DNA from 367 subjects was genotyped for CYP2D6 alleles associated with absent (PM allele: *3, *4, *5, *6, *7, *8, *12, and *14), reduced (IM allele: *9, *10, *17, *29, *41), normal (EM allele), or increased (UM: *XN) enzyme activity. Associations of tamoxifen, metabolites, activity biomarkers, and event-free survival with rapid (UM/EM, UM/IM, EM/EM, EM/IM, or EM/PM alleles) versus slow metabolizers (PM/IM or PM/PM) were investigated through random effects models, with 'study' as the random factor, and Cox regression models, adjusting for confounders. Rapid metabolizers had higher endoxifen levels than slow metabolizers: 15.3 versus 12.2 ng/mL (P = 0.018) with 5 mg/day, and 3.8 versus 2.8 ng/mL (P = 0.004) with 1 mg/day or 10 mg/week tamoxifen. The IGF-I decrease correlated with endoxifen (P = 0.002) and 4-hydroxytamoxifen levels, demonstrating steeper decreases at higher metabolite levels (P = 0.001). After a median follow-up of 12 years, rapid metabolizers with prior history of breast neoplasms allocated to tamoxifen 5 mg/day had a 60 % reduction of risk of recurrences (HR = 0.40, 95 % CI: 0.16-0.99) compared to slow metabolizers. CYP2D6 genotype may have an impact on tamoxifen efficacy at low doses. Trials investigating tamoxifen dose adjustments based on the woman's hormonal context and CYP2D6 genotype are warranted.

Treating gynecologic malignancies with selective estrogen receptor downregulators (SERDs): promise and challenges

Endometrial and ovarian cancers are estrogen-dependent gynecologic malignancies. Although many are estrogen receptor (ER) positive, treatment with the selective estrogen receptor modulator (SERM) tamoxifen, a tissue selective partial-agonist, has demonstrated only modest clinical benefit. Selective estrogen receptor downregulators (SERDs) are pure ER antagonists showing a benefit for advanced ER positive breast cancer, which has bolstered their potential use for ER positive gynecologic malignancies. We summarize these preclinical and clinical data, suggesting that a subpopulation of patients with endometrial or ovarian cancer exists in which treatment with SERDs results in improved outcome. However, the full potential of SERDs for a gynecologic malignancies will be realized only when the appropriate predictive biomarkers are identified. Additionally, a further understanding ER signaling in the context of ovarian and endometrial tissues that appear to involve c-Src and other kinase pathways is needed to successfully address the emergence of resistance with rationally designed combination therapies.

Transformation of tamoxifen and its major metabolites during water chlorination: Identification and in silico toxicity assessment of their disinfection byproducts

The selective estrogen receptor modulator tamoxifen is the most commonly used drug for the treatment and prevention of breast cancer. Tamoxifen is considered as a pro-drug since it is known to exert its pharmacological effect through its major active metabolites, 4-hydroxy-tamoxifen and 4-hydroxy-N-desmethyl-tamoxifen, which are mainly excreted in the urine in the days following administration. In the present work, the reactivity of tamoxifen and its major active metabolites in free chlorine-containing water was investigated for the first time. Under the studied chlorination conditions, tamoxifen was fairly stable whereas its metabolites were quickly degraded. A total of thirteen chlorinated byproducts were tentatively identified by ultra-high performance liquid chromatography coupled to high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometry. Time-course profiles of the identified byproducts were followed in real wastewater samples under conditions that simulate wastewater disinfection. A preliminary assessment of their acute aquatic toxicity at two trophic levels by means of quantitative structure-activity relationship models showed that the identified byproducts were up to 110-fold more toxic than the parent compounds.

The Dual Estrogen Receptor α Inhibitory Effects of the Tissue-Selective Estrogen Complex for Endometrial and Breast Safety

The conjugated estrogen /: bazedoxifene tissue-selective estrogen complex (TSEC) is designed to minimize the undesirable effects of estrogen in the uterus and breast tissues and to allow the beneficial effects of estrogen in other estrogen-target tissues, such as the bone and brain. However, the molecular mechanism underlying endometrial and breast safety during TSEC use is not fully understood. Estrogen receptor α (ERα)-estrogen response element (ERE)-DNA pull-down assays using HeLa nuclear extracts followed by mass spectrometry-immunoblotting analyses revealed that, upon TSEC treatment, ERα interacted with transcriptional repressors rather than coactivators. Therefore, the TSEC-mediated recruitment of transcriptional repressors suppresses ERα-mediated transcription in the breast and uterus. In addition, TSEC treatment also degraded ERα protein in uterine tissue and breast cancer cells, but not in bone cells. Interestingly, ERα-ERE-DNA pull-down assays also revealed that, upon TSEC treatment, ERα interacted with the F-box protein 45 (FBXO45) E3 ubiquitin ligase. The loss-of- and gain-of-FBXO45 function analyses indicated that FBXO45 is involved in TSEC-mediated degradation of the ERα protein in endometrial and breast cells. In preclinical studies, these synergistic effects of TSEC on ERα inhibition also suppressed the estrogen-dependent progression of endometriosis. Therefore, the endometrial and breast safety effects of TSEC are associated with synergy between the selective recruitment of transcriptional repressors to ERα and FBXO45-mediated degradation of the ERα protein.

Clinical and pathological characterization of endometrial cancer in young women: identification of a cohort without classical risk factors

OBJECTIVE

Endometrial cancer (EC) is the most common gynecologic malignancy with known risk factors including excess estrogen and hereditary syndromes. The objective of this study was to determine the proportion of young women with EC that could be attributed to these factors and if, as we suspected, there is a third population of young women in which neither factor is identifiable. We were interested in comparing clinicopathologic characteristics and outcomes across subgroups in order to better inform treatment recommendations.

METHODS

We performed a retrospective chart review of women age 15-49 diagnosed with EC or complex atypical hyperplasia. Demographic, clinicopathologic, treatment, fertility, and outcome parameters were analyzed.

RESULTS

Of 719 women identified, 327 were fully evaluable. 57.5% fit the "High Estrogen" risk criteria. 8.25% met criteria for suspected Lynch syndrome. 34.25% classified as "Neither" had no classical risk factors identified. There were no statistical differences in age, gravidity, tumor grade, treatment selection and response to hormonal therapy. Age of menarche, stage, histology, and synchronous ovarian cancer differed significantly. Prevalence of synchronous ovarian cancer was 21.0% of "Neither", 23.1% of "Lynch", and 6.6% of "High Estrogen". For women who attempted pregnancy, 2/27 of "High Estrogen", 0/3 of "Lynch", and 2/16 of "Neither" achieved a live birth.

CONCLUSIONS

This study confirmed that a third population of young women with EC exist that lack classical risk factors and have distinct clinicopathologic parameters. No difference in success of conservative treatment or live births was noted in the small cohort in whom this treatment approach was attempted.

Medical prevention of breast cancer

Breast cancer is the most common cancer of women in Western Europe and North America. Effective strategies of medical prevention could reduce the burden of breast cancer mortality. The best evidence for a risk reduction exists for hormonal agents such as tamoxifen and raloxifene (22-72%) or aromatase inhibitors (50-65%). However, the severity of side effects and the lack of evidence for an improved survival compromise the risk/benefit balance. In this review the results of chemoprevention studies, including new treatment approaches, are summarized with critical discussion of their use in clinical practice.

Comparative uterotrophic effects of endoxifen and tamoxifen in ovariectomized Sprague-Dawley rats

Endoxifen (4-hydroxy-N-desmethyl-tamoxifen), one of the major active metabolites of tamoxifen, has substantially greater estrogen antagonist properties and antiproliferative effects in breast tumor cells than tamoxifen, a mixed estrogen agonist/antagonist. An associated risk of endometrial cancer and hyperplasia has been linked to the estrogen agonist properties of tamoxifen. We evaluated endoxifen using a classic uterotrophic effects method. Rats were given endoxifen or tamoxifen orally for 3 days. Estradiol was the positive control. Endoxifen and tamoxifen plasma levels exceeded those previously observed clinically. Uterine weight was 3-fold higher in the estradiol group than in the tamoxifen or endoxifen groups, which did not differ from vehicle controls. Tamoxifen and endoxifen caused a greater increase in luminal epithelial cell height than estradiol. Both tamoxifen and endoxifen produced an increase in the stromal BrdU labeling index (LI) that was ≤ estradiol and inversely related to dose, but did not affect luminal epithelial cell BrdU LI. As expected, estradiol increased luminal epithelial cell proliferation. These results indicate that endoxifen induces uterotrophic effects, but is less potent than estradiol in eliciting these effects. Given prior preclinical observations that endoxifen has superior antitumor activity than tamoxifen, the observations of similar uterine effects suggest that the endoxifen risk/benefit ratio may be superior to tamoxifen.

Effect of angiotensin receptor blockade on prevention and reversion of tamoxifen-resistant phenotype in MCF-7 cells

Tamoxifen (TAM) is a standard adjuvant endocrine therapy in postmenopausal breast cancer patients, but innate or acquired TAM resistance has remained to be a therapeutic challenge for clinicians. The aim of this study was to explore the possible participation of renin-angiotensin system (RAS) in the acquisition of TAM resistance and try to prevent and regress the resistance using an angiotensin II receptor type-1 (AGTR1) blocker, losartan. Establishment of TAM-resistant (TAM-R) cells was accomplished by continuous exposure of MCF-7 cells to 1 μmol/L TAM. MTT (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay was performed to determine cell growth. Moreover, messenger RNA (mRNA) expression levels of AGTR1 and angiotensin II receptor type-2 (AGTR2) were measured by quantitative real-time polymerase chain reaction. A significant increase of AGTR1 and AGTR2 transcripts was observed in TAM-R cells compared to MCF-7 cells. Interestingly, losartan-TAM combination effectively resensitized TAM-R cells to tamoxifen treatment by inducing cell death. Therefore, our findings suggest an important role of RAS in acquired TAM resistance and targeting of RAS by losartan may overcome TAM resistance phenomenon and provide a novel avenue for treatment of resistant breast cancers.

No increased venous thromboembolism risk in Asian breast cancer patients receiving adjuvant tamoxifen

Tamoxifen is an effective endocrine treatment for early breast cancer (EBC) but increases the risk of venous thromboembolism. Whether Asian EBC patients (pts) bear the same risk when treated with adjuvant tamoxifen is uncertain. EBC pts diagnosed between 2004 and 2009 were selected from a population database in Taiwan. The pts were followed up from the index date to December 31, 2011 to collect events of deep vein thrombosis (DVT) and pulmonary embolism (PE). Cumulative incidence rates and hazard ratios (HRs) were used to compare the risk between pts treated with and without tamoxifen. In addition, comorbidities were included in an adjusted model of the risk of DVT and PE. A total of 28,029 EBC pts, including 17,843 (63.8 %) in the tamoxifen group and 10,155 (36.2 %) in the nontamoxifen group, were analyzed. The 7-year cumulative incidence rates for DVT and PE were 2.58 and 0.32 % in the tamoxifen group and 2.51 and 0.32 % in the nontamoxifen group (P = 0.92 for DVT, P = 0. 65 for PE), respectively. The HR for the nonadjusted and adjusted models showed no differences in DVT and PE risks between the tamoxifen and nontamoxifen groups. The uterine cancer risk was significantly increased in the pts receiving tamoxifen (adjusted HR = 2.79, P < 0.001), suggesting tamoxifen compliance. The risks of developing DVT and PE are not increased in Asian EBC pts receiving adjuvant tamoxifen. Ethnicity differences should be considered when discussing optimal endocrine treatments with EBC pts.

Duration of tamoxifen use and the risk of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80 %. Tamoxifen treatment of the first cancer has been associated with a reduction in the risk of a subsequent contralateral cancer. We studied 1,504 women with a known BRCA1 or BRCA2 mutation, 411 women with bilateral breast cancer (cases) and 1,093 women with unilateral breast cancer (controls) in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of first breast cancer as the cases. For each woman who used tamoxifen, the starting and stopping dates were abstracted and the duration of tamoxifen use was calculated. Three hundred and thirty-one women had used tamoxifen (22 %); of these 84 (25 %) had completed four or more years of tamoxifen, the remainder stopped prematurely or were current users. For women with up to 1 year of tamoxifen use, the odds ratio for contralateral breast cancer was 0.37 (95 % CI 0.20-0.69; p = 0.001) compared to women with no tamoxifen use. Among women with 1-4 years of tamoxifen use the odds ratio was 0.53 (95 % CI 0.32-0.87; p = 0.01). Among women with four or more years of tamoxifen use the odds ratio was 0.83 (95 % CI 0.44-1.55; p = 0.55). Short-term use of tamoxifen for chemoprevention in BRCA1 and BRCA2 mutation carriers may be as effective as a conventional 5-year course of treatment.

Tamoxifen for women at high risk of breast cancer

Tamoxifen has been used as a treatment for women who have been diagnosed with breast cancer for roughly four decades and has been approved as chemoprevention for over ten years. Although tamoxifen has been proven to be beneficial in preventing breast cancer in high-risk women, its use has not been widely embraced. To some extent, this is due to several of its side effects, including an increased risk of endometrial cancer and pulmonary embolism, but these serious side effects are rare. The risks and benefits of tamoxifen chemoprevention should be considered for each patient.

Endometrial cancer incidence in breast cancer patients correlating with age and duration of tamoxifen use: a population based study

Background: Our study aimed to assess the endometrial cancer risk after tamoxifen adjuvant treatment for female breast cancer patients in Taiwan.

Materials and Methods: A total of 74,280 breast cancer patients between January 1997 and December 2004 were included in the study; 39,411 received tamoxifen treatment and 34,869 did not. Tamoxifen-associated endometrial cancer was defined as endometrial cancer that occurred in patients at least 6-month after the diagnosis of breast cancer, who underwent tamoxifen treatment.

Results: A total of 222 patients developed endometrial cancer, and of these,153 (69 %) were seen in patients with tamoxifen treatment, and 69 (31%) were seen in patients without the use of tamoxifen. The incidence of endometrial cancer was 0.388% (153/39,411) in patients with tamoxifen treatment, while was 0.198% (69/34,869) in patients without tamoxifen treatment. Logistic regression analysis demonstrated that tamoxifen use and age over 35 years were significantly correlated with development of endometrial cancer (p<0.001 and p=0.002, respectively). The odds ratio was 2.94 (95%CI, 2.13-4.06) for 3 years or longer tamoxifen use. The odds ratio was 4.08 (95%CI, 1.67-9.93) for women older than 35 years compared to those 35 or younger than 35 years. There were no significant differences in prior hormone exposure, hypertension and diabetes.

Conclusions: To the best of our knowledge, this is the largest population based study that shows in patients with breast cancer, tamoxifen use for more than three years or patients older than 35 years was associated with a significantly increased risk for developing endometrial cancer.