Randomized Dose-Ranging Trial of Tamoxifen at Low Doses in Hormone Replacement Therapy Users

Tamoxifen Dose De-Escalation: An Effective Strategy for Reducing Adverse Effects?

Tamoxifen, a cornerstone in the adjuvant treatment of estrogen receptor-positive breast cancer, significantly reduces breast cancer recurrence and breast cancer mortality; however, its standard adjuvant dose of 20 mg daily presents challenges due to a broad spectrum of adverse effects, contributing to high discontinuation rates. Dose reductions of tamoxifen might be an option to reduce treatment-related toxicity, but large randomized controlled trials investigating the tolerability and, more importantly, efficacy of low-dose tamoxifen in the adjuvant setting are lacking. We conducted an extensive literature search to explore evidence on the tolerability and clinical efficacy of reduced doses of tamoxifen. In this review, we discuss two important topics regarding low-dose tamoxifen: (1) the incidence of adverse effects and quality of life among women using low-dose tamoxifen; and (2) the clinical efficacy of low-dose tamoxifen examined in the preventive setting and evaluated through the measurement of several efficacy derivatives. Moreover, practical tools for tamoxifen dose reductions in the adjuvant setting are provided and further research to establish optimal dosing strategies for individual patients are discussed.

Photobiomodulation for Blood Pressure and Heart Rate Reduction in Mastectomized Women on Hormone Blockers: A Randomized Controlled Trial

Objective: To assess the impact of intravascular laser irradiation of blood (ILIB) on the primitive carotid artery (PCA) hemodynamic variables, specifically blood pressure (BP) and heart rate (HR), in mastectomized patients undergoing hormone blocker treatments. Materials and methods: This study is a controlled, experimental, and randomized clinical trial. Patients were allocated into two groups: the experimental group (G1)-patients who received ILIB therapy using a 660 nm laser targeted at the PCA, and the control group (G2)-patients who did not receive ILIB therapy. Clinical research was conducted weekly, with measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR. The Mann-Whitney U test for independent samples was used, with a significance level of α = 0.05. Results: Systemic photobiomodulation on the PCA did not demonstrate a statistically significant difference in relation to SBP and DBP. However, for HR, the p-value was <0.05, indicating a significant difference between G1 and G2. The initial mean p > decreased from 142.3 to 116.4 mmHg in G1, and from 130.4 to 119.8 mmHg in G2. The DBP varied from 78.8 to 72.8 mmHg in G1, and from 79.1 to 74.2 mmHg in G2. A statistically significant difference was observed in HR, decreasing from 81.3 to 62.06 bpm in G1, and changing minimally from 74.1 to 75.1 bpm in G2. A considerable reduction was present in the timing of application. Conclusions: ILIB therapy applied to the PCA induces a reduction in BP and, more notably, HR in mastectomized women using the tamoxifen or aromatase inhibitors.

Radiotherapy versus low-dose tamoxifen following breast-conserving surgery for low-risk and estrogen receptor-positive breast ductal carcinoma in situ: an international open-label randomized non-inferiority trial (TBCC-ARO DCIS Trial)

BACKGROUND

Radiotherapy (RT) following breast-conserving surgery (BCS) is mainly used to decrease the rate of ipsilateral breast tumor recurrence (IBTR) in women with breast ductal carcinoma in situ (DCIS). Recent studies have demonstrated that low-dose tamoxifen significantly reduces IBTR in breast DCIS. Here, we aim to determine whether the administration of low-dose tamoxifen is non-inferior to RT in preventing IBTR in patients with low-risk characteristics of breast DCIS.

METHODS/DESIGN

This is a prospective, international, open-label, randomized, non-inferiority trial. Patients with low-risk clinicopathologic features (> 40 years old, low risk of breast cancer susceptibility gene (BRCA) 1 and BRCA2 mutations, mammographically detected unicentric and non-mass lesions, low- or intermediate-grade without comedo or necrosis, measuring < 2.5 cm with margins ≥ 3 mm, and estrogen receptor-positive status) of DCIS who underwent BCS will be randomized at a 1:1 ratio to either receive tamoxifen (5 mg/day) for 5 years or undergo RT with conventional fractions (50 Gy in 25 fractions) or hypofractionations (40.05 Gy in 15 fractions). Randomization will be stratified by the Taiwan Breast Cancer Consortium. As approximately 5% of patients cannot tolerate the side effects of low-dose tamoxifen and will receive RT, we estimate that 405 patients will be randomized to a low-dose tamoxifen arm and 405 patients to the RT arm, according to a non-inferiority margin within 5% of IBTR difference and 90% β-power noticing non-inferiority. The primary endpoints are breast tumor recurrence, including ipsilateral, regional, contralateral, and distant recurrence of breast DCIS or invasive cancer. The secondary endpoints are overall survival and adverse effects of RT and tamoxifen. Translational studies will also be conducted for this trial.

DISCUSSION

This is the first non-inferiority trial on breast DCIS. This study will provide an important recommendation for clinical physicians on whether to use low-dose adjuvant tamoxifen for patients with low-risk breast DCIS who do not want to receive adjuvant RT.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT04046159, Registered on April 30, 2019.

Eligibility criteria for Menopausal Hormone Therapy (MHT): a position statement from a consortium of scientific societies for the use of MHT in women with medical conditions. MHT Eligibility Criteria Group

This project aims to develop eligibility criteria for menopausal hormone therapy (MHT). The tool should be similar to those already established for contraception A consortium of scientific societies coordinated by the Spanish Menopause Society met to formulate recommendations for the use of MHT by women with medical conditions based on the best available evidence. The project was developed in two phases. As a first step, we conducted 14 systematic reviews and 32 metanalyses on the safety of MHT (in nine areas: age, time of menopause onset, treatment duration, women with thrombotic risk, women with a personal history of cardiovascular disease, women with metabolic syndrome, women with gastrointestinal diseases, survivors of breast cancer or of other cancers, and women who smoke) and on the most relevant pharmacological interactions with MHT. These systematic reviews and metanalyses helped inform a structured process in which a panel of experts defined the eligibility criteria according to a specific framework, which facilitated the discussion and development process. To unify the proposal, the following eligibility criteria have been defined in accordance with the WHO international nomenclature for the different alternatives for MHT (category 1, no restriction on the use of MHT; category 2, the benefits outweigh the risks; category 3, the risks generally outweigh the benefits; category 4, MHT should not be used). Quality was classified as high, moderate, low or very low, based on several factors (including risk of bias, inaccuracy, inconsistency, lack of directionality and publication bias). When no direct evidence was identified, but plausibility, clinical experience or indirect evidence were available, "Expert opinion" was categorized. For the first time, a set of eligibility criteria, based on clinical evidence and developed according to the most rigorous methodological tools, has been defined. This will provide health professionals with a powerful decision-making tool that can be used to manage menopausal symptoms.

Alternative dosing of exemestane in postmenopausal women with ER-positive breast cancer. Design and methods of a randomized presurgical trial

Introduction:

Aromatase inhibitors are effective in lowering breast cancer incidence among postmenopausal women, but adverse events represent a barrier to their acceptability and adherence as a preventive treatment. This study aims to assess whether lowering exemestane schedule may retain biological activity while improving tolerability in breast cancer patients.

Methods/design:

We are conducting a, pre-surgical, non-inferiority phase IIb study in postmenopausal women with newly diagnosed estrogen receptor-positive breast cancer. Participants are randomized to receive either exemestane 25 mg/day or 25 mg/three times-week or once a week for 4 to 6 weeks prior to surgery.

The primary endpoint is the percentage change of serum estradiol concentration between baseline and surgery comparing the three arms. Sample size of 180 women was calculated assuming a 6% non-inferiority of the percent change of estradiol in the lower dose arms compared with the 80% decrease predicted in the full dose arm, with 80% power and using a one-sided 5% significance level and a two-sample t-test.

Main secondary outcomes are: safety; change in Ki-67 in cancer and adjacent pre-cancer tissue, circulating sex hormones, adipokines, lipid profile, insulin and glucose changes, in correlation with drug and metabolites concentrations.

Results and discussion:

The present paper is focused on methodology and operational aspects of the study. A total of 180 participants have ben enrolled. The trial is still blinded, and the analyses are ongoing.

Despite the short term duration, results may have relevant implications for clinical management of women at increased risk of developing a ER positive breast cancer.

Endocrine prevention of breast cancer

Breast cancer (BC) is the most common non-cutaneous malignancy among women worldwide and is a significant cause of morbidity, mortality, and national health care expenditure. Unfortunately, with few exceptions like alcohol consumption, obesity, and physical activity, most BC risk factors are unmodifiable. Antiestrogen endocrine therapy, commonly known as BC chemoprevention, is an effective method of BC prevention. In multiple randomized trials, two selective estrogen receptor modulators - tamoxifen and raloxifene, and two aromatase inhibitors - exemestane and anastrozole have reduced BC incidence by 50%-65% in high-risk women. An estimated 15% of the US women between 35 and 79 years of age may qualify as high risk for BC, yet a small percentage of these women will ever have a formal BC risk assessment or a discussion of endocrine prevention options. The etiology of underutilization of endocrine prevention of BC is multifactorial - infrequent use of BC risk assessment tools in the primary care settings, insufficient knowledge of BC risk assessment tools and antiestrogen agents among primary care providers, concerns of side effects, inadequate time for counseling during primary care visit, and lack of predictive biomarkers may play significant roles. Many small studies incorporating risk assessment tools and decision-making aids showed minimal success in enhancing endocrine prevention. One critical factor for underutilization of endocrine prevention is low uptake of endocrine prevention by high-risk women even when appropriately recommended. Furthermore, adherence to BC endocrine prevention is unsatisfactorily low. Despite the current infrequent usage, endocrine prevention has the potential to reduce the public health burden of BC significantly. Innovative approaches like finding new agents, alternative dosing and schedule of currently available agents, transdermal medication delivery, increased public and professional awareness, and policymakers' commitments may bring the desired changes.

Low-Dose Tamoxifen for Mammographic Density Reduction: A Randomized Controlled Trial

Tamoxifen prevents breast cancer in high-risk women and reduces mortality in the adjuvant setting. Mammographic density change is a proxy for tamoxifen therapy response. We tested whether lower doses of tamoxifen were noninferior to reduce mammographic density and associated with fewer symptoms.

Links between Inflammation and Postoperative Cancer Recurrence

Despite complete resection, cancer recurrence frequently occurs in clinical practice. This indicates that cancer cells had already metastasized from their organ of origin at the time of resection or had circulated throughout the body via the lymphatic and vascular systems. To obtain this potential for metastasis, cancer cells must undergo essential and intrinsic processes that are supported by the tumor microenvironment. Cancer-associated inflammation may be engaged in cancer development, progression, and metastasis. Despite numerous reports detailing the interplays between cancer and its microenvironment via the inflammatory network, the status of cancer-associated inflammation remains difficult to recognize in clinical settings. In the current paper, we reviewed clinical reports on the relevance between inflammation and cancer recurrence after surgical resection, focusing on inflammatory indicators and cancer recurrence predictors according to cancer type and clinical indicators.

Breast Cancer and Tamoxifen: A Nigerian Perspective to Effective Personalised Therapy

Estrogen-receptor positivity in tumour, often requiring long-term tamoxifen therapy, is thought to characterise between 43% and 65% of breast cancer cases in Nigeria. The patient population is further marked by late-stage diagnosis which significantly heightens the tendency for tumour relapse in the course of tamoxifen therapy. Despite tamoxifen being considered a reliable chemopreventive in high-risk individuals and an effective adjuvant therapy for hormone-sensitive tumours, mortality has remained high among breast cancer patients in the West African region where Nigeria belongs. The Nigerian breast cancer population, like other similar patient-populations in the West African region, provides a mix of intrinsic genome-diversity and perhaps unique tumour biology and evolution. These peculiarities suggest the need for a rational approach to tumour management and a personalised delivery of therapy in Nigeria's dominant estrogen-receptor-positive patient population. Herein, critical indices of tamoxifen-therapy success are discussed in the context of the Nigerian breast cancer population with emphasis on salient aspects of tamoxifen-biotransformation, host- and tumour-genomics, and epigenetics.

Estimating the magnitude of clinical benefit of systemic therapy in patients with DCIS or pre-invasive disease of the breast

The challenge of effective management of ductal carcinoma in situ (DCIS) and other pre-malignant disorders of the breast is to select patients who will not progress to invasive carcinoma from those at the highest risk who require radiotherapy and/or endocrine therapy to minimize the risk of a subsequent invasive recurrence. Although IBIS-II and NSABP-B35 DCIS phase III trials proved that tamoxifen 20 mg/day and anastrozole reduce the risk of ipsilateral and contralateral events, the toxicities of both drugs have hampered the drug uptake by high-risk women. We recently reported results of a 3-year placebo-controlled trial of low-dose (5 mg/d) tamoxifen in 500 women with intraepithelial neoplasia (70% DCIS). At a median follow-up of 5 years, women randomly assigned to low-dose tamoxifen had half the number of subsequent diagnoses of DCIS or invasive cancer compared with those randomly assigned to placebo but no increase in thromboembolic events or endometrial cancers. The 5-year number needed to treat was 22 (95% CI, 20-27). Our attention is now focused on prognostic and predictive markers to identify patients who can derive the greatest benefits from low dose tamoxifen, such as for instance the expression of 23 genes involved in cell cycle progression (CCP). In conclusion, we endorse an active treatment of DCIS as the standard of care.

Randomized Placebo Controlled Trial of Low-Dose Tamoxifen to Prevent Local and Contralateral Recurrence in Breast Intraepithelial Neoplasia

PURPOSE

Tamoxifen administered for 5 years at 20 mg/d is effective in breast cancer treatment and prevention, but toxicity has limited its broad use. Biomarker trials showed that 5 mg/d is not inferior to 20 mg/d in decreasing breast cancer proliferation. We hypothesized that a lower dose given for a shorter period could be as effective in preventing recurrence from breast intraepithelial neoplasia but have a lower toxicity than the standard dose.

PATIENTS AND METHODS

We conducted a multicenter randomized trial of tamoxifen, 5 mg/d or placebo administered for 3 years after surgery in women with hormone-sensitive or unknown breast intraepithelial neoplasia, including atypical ductal hyperplasia and lobular or ductal carcinoma in situ. The primary end point was the incidence of invasive breast cancer or ductal carcinoma in situ.

RESULTS

Five hundred women 75 years of age or younger were included. After a median follow-up of 5.1 years (interquartile range, 3.9-6.3 years), there were 14 neoplastic events with tamoxifen and 28 with placebo (11.6 v 23.9 per 1,000 person-years; hazard ratio, 0.48; 95% CI, 0.26 to 0.92; P = .02), which resulted in a 5-year number needed to treat of 22 (95% CI, 20 to 27). Tamoxifen decreased contralateral breast events by 75% (three v 12 events; hazard ratio, 0.25; 95% CI, 0.07 to 0.88; P = .02). Patient-reported outcomes were not different between arms except for a slight increase in frequency of daily hot flashes with tamoxifen (P = .02). There were 12 serious adverse events with tamoxifen and 16 with placebo, including one deep vein thrombosis and one stage I endometrial cancer with tamoxifen and one pulmonary embolism with placebo.

CONCLUSION

Tamoxifen at 5 mg/d for 3 years can halve the recurrence of breast intraepithelial neoplasia with a limited toxicity, which provides a new treatment option in these disorders.

Impact of short-term low-dose tamoxifen on molecular breast imaging background parenchymal uptake: a pilot study

BACKGROUND

High background parenchymal uptake (BPU) on molecular breast imaging (MBI) has been identified as a breast cancer risk factor. We explored the feasibility of offering a short-term intervention of low-dose oral tamoxifen to women with high BPU and examined whether this intervention would reduce BPU.

METHODS

Women with a history of high BPU and no breast cancer history were invited to the study. Participants had an MBI exam, followed by 30 days of low-dose oral tamoxifen at either 5 mg or 10 mg/day, and a post-tamoxifen MBI exam. BPU on pre- and post-tamoxifen MBI exams was quantitatively assessed as the ratio of average counts in breast fibroglandular tissue vs. average counts in subcutaneous fat. Pre-tamoxifen and post-tamoxifen BPU were compared with paired t tests.

RESULTS

Of 47 women invited, 22 enrolled and 21 completed the study (10 taking 5 mg tamoxifen, 11 taking 10 mg tamoxifen). Mean age was 47.7 years (range 41-56 years). After 30 days low-dose tamoxifen, 8 of 21 women (38%) showed a decline in BPU, defined as a decrease from the pre-tamoxifen MBI of at least 15%; 11 of 21 (52%) had no change in BPU (within ± 15%); 2 of 21 (10%) had an increase in BPU of greater than 15%. Overall, the average post-tamoxifen BPU was not significantly different from pre-tamoxifen BPU (1.34 post vs. 1.43 pre, p = 0.11). However, among women taking 10 mg tamoxifen, 5 of 11 (45%) showed a decline in BPU; average BPU was 1.19 post-tamoxifen vs. 1.34 pre-tamoxifen (p = 0.005). In women taking 5 mg tamoxifen, 2 of 10 (20%) showed a decline in BPU; average BPU was 1.51 post-tamoxifen vs.1.53 pre-tamoxifen (p = 0.99).

CONCLUSIONS

Short-term intervention with low-dose tamoxifen may reduce high BPU on MBI for some patients. Our preliminary findings suggest that 10 mg tamoxifen per day may be more effective than 5 mg for inducing declines in BPU within 30 days. Given the variability in BPU response to tamoxifen observed among study participants, future study is warranted to determine if BPU response could predict the effectiveness of tamoxifen for breast cancer risk reduction within an individual.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02979301 . Registered 01 December 2016.

Quality of Life in a Randomized Breast Cancer Prevention Trial of Low-Dose Tamoxifen and Fenretinide in Premenopausal Women

Menopausal symptoms are the main reason for withdrawal in tamoxifen prevention trials. Here, we present Menopause Quality of Life (MenQoL) assessment within a randomized 2 × 2 phase II clinical trial of low-dose tamoxifen and the synthetic retinoid fenretinide. A total of 235 premenopausal women at higher risk for breast cancer were randomized to either tamoxifen 5 mg daily, fenretinide 200 mg daily, their combination, or placebo. Climacteric symptoms were investigated using the MenQoL questionnaire which was self-administered at each visit for 2 years of treatment and for 1 year of follow-up. CYP2D6 was genotyped in subjects taking tamoxifen to study the association with menopausal symptoms. The MenQoL effect size analysis showed no statistically significant difference among the four treatment arms for all four domains (vasomotor, physical, psychosocial, and sexual). Vasomotor symptoms only slightly increased under tamoxifen, with a score at year two of 1.45, 1.21, 0.58, and 1.17 in the combined, tamoxifen, fenretinide, and placebo arms, respectively. Compared with the slow metabolizers, a higher percentage of subjects with CYP2D6 extensive metabolizer genotype complained of a ≥3 score in the vasomotor, psychosocial, and sexual domain in the tamoxifen arms (P value = 0.01, 0.007, and 0.007, respectively). QoL in premenopausal or perimenopausal women was not significantly worsened by low-dose tamoxifen or fenretinide. Our findings suggest that a low dose of tamoxifen may increase its acceptability for breast cancer prevention.

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.

Worry and risk perception of breast cancer in a prevention trial of low dose tamoxifen in midlife postmenopausal hormone users

OBJECTIVE

There is increasing interest in combining postmenopausal hormone therapy (HT) and SERMs in midlife women. We previously showed that refusal to participate in a prevention trial of low dose tamoxifen in HT users was associated with higher worry about breast cancer. Given this counterintuitive finding, we studied which factors influenced worry and risk perception of breast cancer.

METHODS

We assessed the relationships of breast cancer worry and risk perception with age, age at menopause, Gail risk, education, adherence to mammographic screening, BMI, smoking, physical activity, alcohol use, anxiety and depression in 457 midlife HT users who were eligible to participate in the trial.

RESULTS

Women with menopause <48 years were more worried about breast cancer than women with menopause >52 years (OR = 5.0, 95% CI, 1.2-21.1). Worry was also associated with high absolute risk perception and former smoking. Factors associated with higher risk perception were age>60 years, at-risk life style, worry about breast cancer and depression.

CONCLUSIONS

The inverse association between early menopause and worry about breast cancer is in contrast with the known protective effect of early menopause on breast cancer risk and seems to reflect a feeling of aging and disease vulnerability. Our findings indicate that worry about cancer has an affective construct which is independent of breast cancer biology but is engaged in health decision making. Increasing breast cancer risk awareness in subjects high in worry without a plan of emotional coping may therefore be counterproductive because of avoidant attitudes.

How do we increase uptake of tamoxifen and other anti-estrogens for breast cancer prevention?

Several randomized controlled trials of anti-estrogens, such as tamoxifen and aromatase inhibitors, have demonstrated up to a 50–65% decrease in breast cancerincidence among high-risk women. Approximately 15% of women, age 35–79 years, in the U.S. meet criteria for breast cancer preventive therapies, but uptake of these medications remain low. Explanations for this low uptake includelack of awareness of breast cancer risk status, insufficient knowledge about breast cancer preventive therapies among patients and physicians, and toxicity concerns. Increasing acceptance of pharmacologic breast cancer prevention will require effective communication of breast cancer risk, accurate representation about the potential benefits and side effects of anti-estrogens, targeting-specific high-risk populations most likely to benefit from preventive therapy, and minimizing the side effects of current anti-estrogens with novel administration and dosing options. One strategy to improve the uptake of chemoprevention strategies is to consider lessons learned from the use of drugs to prevent other chronic conditions, such as cardiovascular disease. Enhancing uptake and adherence to anti-estrogens for primary prevention holds promise for significantly reducing breast cancer incidence, however, this will require a significant change in our current clinical practice and stronger advocacy and awareness at the national level.

Adjuvant therapy in patients with ductal carcinoma in situ of the breast: The Pandora's box

Most patients with ductal carcinoma in situ of the breast (DCIS) are eligible for breast conservation treatment. The key management decision is whether to add radiotherapy and/or endocrine therapy to minimize the risk of a subsequent recurrence. Recent analyses indicating a lack of benefit in terms of breast cancer-associated mortality have suggested that more conservative approaches, omitting adjuvant therapy or even surgery, may be advisable in selected patients. These mortality observations are directly influenced by widespread use of mammographic screening which has opened a Pandora's box of subclinical DCIS and early invasive lesions. Confusion as to how aggressively such possibly indolent lesions should be treated has led to misunderstandings among patients and medical professionals. While awaiting further prospective evidence from clinical trials, we endorse an active treatment of DCIS as the standard of care. Our rationale is twofold: invasive recurrences are associated with an increase in breast cancer mortality, which is not the only relevant endpoint for DCIS. The benefit of complete surgical excision, adjuvant radiotherapy and endocrine treatment in preventing recurrence and invasive progression has been demonstrated in DCIS. The challenge now is how to identify DCIS patients who will not progress to invasive carcinoma even without complete excision and, at the other extreme, those patients at the highest risk who require mastectomy for local control. The current controversies over whether and which adjuvant therapy should be implemented can at least in part be addressed by developing effective doctor-patient communications that enable mutual understanding about the management of this biologically heterogeneous disease.

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.

Addressing barriers to uptake of breast cancer chemoprevention for patients and providers

Breast cancer is the most common malignancy among women in the United States, and the primary prevention of this disease is a major public health issue. Because there are relatively few modifiable breast cancer risk factors, pharmacologic interventions with antiestrogens have the potential to significantly affect the primary prevention setting. Breast cancer chemoprevention with selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene, and with aromatase inhibitors (AIs) exemestane and anastrozole, is underutilized despite several randomized controlled trials demonstrating up to a 50% to 65% relative risk reduction in breast cancer incidence among women at high risk. An estimated 10 million women in the United States meet high-risk criteria for breast cancer and are potentially eligible for chemoprevention, but less than 5% of women at high risk who are offered antiestrogens for primary prevention agree to take it. Reasons for low chemoprevention uptake include lack of routine breast cancer risk assessment in primary care, inadequate time for counseling, insufficient knowledge about antiestrogens among patients and providers, and concerns about side effects. Interventions designed to increase chemoprevention uptake, such as decision aids and incorporating breast cancer risk assessment into clinical practice, have met with limited success. Clinicians can help women make informed decisions about chemoprevention by effectively communicating breast cancer risk and enhancing knowledge about the risks and benefits of antiestrogens. Widespread adoption of chemoprevention will require a major paradigm shift in clinical practice for primary care providers (PCPs). However, enhancing uptake and adherence to breast cancer chemoprevention holds promise for reducing the public health burden of this disease.

Current perspectives of molecular pathways involved in chronic inflammation-mediated breast cancer

Inflammation has multifaceted role in cancer progression including initiation, promotion and invasion by affecting the immune surveillance and associated signaling pathways. Inflammation facilitates the over-expression of cytokines, chemokines and growth factors involved in progression of different cancers including breast cancer progression. Deregulation of biological processes such as oxidative stress, angiogenesis, and autophagy elicit favorable immune response towards chronic inflammation. Apart from the role in carcinogenesis, chronic inflammation also favors the emergence of drug resistance clones by inducing the growth of breast cancer stem-like cells. Immunomodulation mediated by cytokines, chemokines and several other growth factors present in the tumor microenvironment regulate chronic inflammatory response and alter crosstalk among various signaling pathways such as NF-κB, Nrf-2, JAK-STAT, Akt and MAPKs involved in the progression of breast cancer. In this review, we focused on cellular and molecular processes involved in chronic inflammation, crosstalk among different signaling pathways and their association in breast cancer pathogenesis.

Alternate dosing schedules for cancer chemopreventive agents

Pharmacologic interventions for cancer risk reduction involve the chronic administration of synthetic or natural agents to reduce or delay the occurrence of malignancy. Despite the strong evidence for a favorable risk-benefit ratio for a number of agents in several common malignancies such as breast and prostate cancer, the public's attitude toward cancer chemoprevention remains ambivalent, with the issue of toxicity associated with drugs being perceived as the main barrier to widespread use of preventive therapy by high-risk subjects. Among the strategies to overcome such obstacles to preventive therapies, two novel and potentially safer modes of administering agents are discussed in this paper. The first strategy is to lower the dose of drugs that are in common use in the adjuvant setting based on the notion that prevention of cancer cells from developing should require a lower dose than eradicating established tumor cells. A second approach is to adopt an intermittent administration similar to what is used in the chemotherapy setting in an attempt to minimize risks while retaining benefits. This article provides a detailed discussion of the principles and future development of these two approaches in the direction of a precision preventive medicine.

Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies

Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disordering effect for DSPC MLVs both in the gel and liquid crystalline phases. The bandwidth values of the CH2 stretchings except for 1 mol% increased when TAM concentrations increased for DSPC liposomes, indicating an increase in the dynamics of liposomes. The CO stretching and PO2- antisymmetric double bond stretching bands were analyzed to study interactions of TAM with head groups of lipids. As the concentrations of TAM increased, dehydration occurred around these functional groups in the polar part of the lipids. The DSC studies on thermal properties of DSPC lipids indicate that TAM eliminated the pre transition, shifted the main phase transition to lower temperatures and broadened the phase transition curve of the liposomes.

Critical research gaps and translational priorities for the successful prevention and treatment of breast cancer

INTRODUCTION

Breast cancer remains a significant scientific, clinical and societal challenge. This gap analysis has reviewed and critically assessed enduring issues and new challenges emerging from recent research, and proposes strategies for translating solutions into practice.

METHODS

More than 100 internationally recognised specialist breast cancer scientists, clinicians and healthcare professionals collaborated to address nine thematic areas: genetics, epigenetics and epidemiology; molecular pathology and cell biology; hormonal influences and endocrine therapy; imaging, detection and screening; current/novel therapies and biomarkers; drug resistance; metastasis, angiogenesis, circulating tumour cells, cancer 'stem' cells; risk and prevention; living with and managing breast cancer and its treatment. The groups developed summary papers through an iterative process which, following further appraisal from experts and patients, were melded into this summary account.

RESULTS

The 10 major gaps identified were: (1) understanding the functions and contextual interactions of genetic and epigenetic changes in normal breast development and during malignant transformation; (2) how to implement sustainable lifestyle changes (diet, exercise and weight) and chemopreventive strategies; (3) the need for tailored screening approaches including clinically actionable tests; (4) enhancing knowledge of molecular drivers behind breast cancer subtypes, progression and metastasis; (5) understanding the molecular mechanisms of tumour heterogeneity, dormancy, de novo or acquired resistance and how to target key nodes in these dynamic processes; (6) developing validated markers for chemosensitivity and radiosensitivity; (7) understanding the optimal duration, sequencing and rational combinations of treatment for improved personalised therapy; (8) validating multimodality imaging biomarkers for minimally invasive diagnosis and monitoring of responses in primary and metastatic disease; (9) developing interventions and support to improve the survivorship experience; (10) a continuing need for clinical material for translational research derived from normal breast, blood, primary, relapsed, metastatic and drug-resistant cancers with expert bioinformatics support to maximise its utility. The proposed infrastructural enablers include enhanced resources to support clinically relevant in vitro and in vivo tumour models; improved access to appropriate, fully annotated clinical samples; extended biomarker discovery, validation and standardisation; and facilitated cross-discipline working.

CONCLUSIONS

With resources to conduct further high-quality targeted research focusing on the gaps identified, increased knowledge translating into improved clinical care should be achievable within five years.

Effect of low-dose tamoxifen after surgical excision of ductal intraepithelial neoplasia: results of a large retrospective monoinstitutional cohort study

BACKGROUND

Postsurgical treatment of ductal intraepithelial neoplasia (DIN) with standard doses of tamoxifen has not reached a consensus yet. Given positive results of low-dose tamoxifen on breast cancer biomarkers modulation, we analyzed a large cohort of DIN patients treated with low-dose tamoxifen or no treatment as per institutional guidelines.

PATIENTS AND METHODS

All consecutive women operated on at the European Institute of Oncology for estrogen receptor (ER)-positive DIN (474 treated with low-dose tamoxifen and 509 untreated patients) were followed up for a median of 7 years.

RESULTS

Compared with untreated patients, a significant 30% reduction in breast cancer risk was observed on low-dose tamoxifen with an adjusted hazard ratio (HR) = 0.70 [95% confidence interval (CI) 0.51-0.94], with a greater benefit in postmenopausal (HR = 0.57; 95% CI 0.34-0.94) than in premenopausal women (HR = 0.79; 95% CI 0.54-1.17). Treated patients with ER and progesterone receptor (PgR) >50% DIN had a lower incidence of breast events than untreated ones (HR = 0.61; 95% CI 0.40-0.94), whereas no protective effect has been observed in patients with ER or PgR <50% DIN. Drug discontinuation resulted in a doubled risk of recurrence in premenopausal women only (HR = 1.95; 95% CI 0.98-3.89). No excess of endometrial cancer occurred.

CONCLUSIONS

Low-dose tamoxifen is a promising and safe strategy for highly endocrine responsive DIN. Treatment adherence is crucial in premenopausal women. A definitive trial is ongoing.

A randomized phase II presurgical trial of weekly low-dose tamoxifen versus raloxifene versus placebo in premenopausal women with estrogen receptor-positive breast cancer

Introduction

We previously demonstrated that 1 or 5 mg per day of tamoxifen (T) given for four weeks before surgery reduces Ki-67 in breast cancer (BC) patients to the same extent as the standard 20 mg/d. Given the long half-life of T, a weekly dose (10 mg per week (w)) may be worth testing. Also, raloxifene (R) has shown Ki-67 reduction in postmenopausal patients in a preoperative setting, but data in premenopausal women are limited. We conducted a randomized trial testing T 10 mg/w vs. R 60 mg/d vs. placebo in a presurgical model.

Methods

Out of 204 screened subjects, 57 were not eligible, 22 refused to participate and 125 were included in the study. The participants were all premenopausal women with estrogen receptor-positive BC. They were randomly assigned to either T 10mg/w or R 60 mg/d or placebo for six weeks before surgery. The primary endpoint was tissue change of Ki-67. Secondary endpoints were modulation of estrogen and progesterone receptors and several other circulating biomarkers.

Results

Ki-67 was not significantly modulated by either treatment. In contrast, both selective estrogen receptor modulators (SERMs) significantly modulated circulating IGF-I/IGFBP-3 ratio, cholesterol, fibrinogen and antithrombin III. Estradiol was increased with both SERMs. Within the tamoxifen arm, CYP2D6 polymorphism analysis showed a higher concentration of N-desTamoxifen, one of the tamoxifen metabolites, in subjects with reduced CYP2D6 activity. Moreover, a reduction of Ki-67 and a marked increase of sex hormone-binding globulin (SHBG) were observed in the active phenotype.

Conclusions

A weekly dose of tamoxifen and a standard dose of raloxifene did not inhibit tumor cell proliferation, measured as Ki-67 expression, in premenopausal BC patients. However, in the tamoxifen arm women with an extensive phenotype for CYP2D6 reached a significant Ki-67 modulation.

Tailoring treatment for ductal intraepithelial neoplasia of the breast according to Ki-67 and molecular phenotype

Background:

The post-surgical management of ductal intraepithelial neoplasia (DIN) of the breast is still a dilemma. Ki-67 labelling index (LI) has been proposed as an independent predictive and prognostic factor in early breast cancer.

Methods:

The prognostic and predictive roles of Ki-67 LI were evaluated with a multivariable Cox regression model in a cohort of 1171 consecutive patients operated for DIN in a single institution from 1997 to 2007.

Results:

Radiotherapy (RT) was protective in subjects with DIN with Ki-67 LI ≥14%, whereas no evidence of benefit was seen for Ki-67 LI <14%, irrespective of nuclear grade and presence of necrosis. Notably, the higher the Ki-67 LI, the stronger the effect of RT (P-interaction <0.01). Hormonal therapy (HT) was effective in both Luminal A (adjusted hazard ratio (HR)=0.56 (95% CI, 0.33–0.97)) and Luminal B/Her2neg DIN (HR 0.51 (95% CI, 0.27–0.95)).

Conclusion:

Our data suggest that Ki-67 LI may be a useful prognostic and predictive adjunct in DIN patients. The Ki-67 LI of 14% could be a potential cutoff for better categorising this population of women at increased risk for breast cancer and in which adjuvant treatment (RT, HT) should be differently addressed, independent of histological grade and presence of necrosis.

Exemestane: one part of the chemopreventive spectrum for ER-positive breast cancer

Development of drugs to prevent breast cancer has focused largely on anti-estrogenic agents, leading to approval by the US FDA of two such agents for this purpose: tamoxifen and raloxifene. However, the uptake of these drugs by high-risk women and their primary care physicians has been limited, due in large part to a perceived unfavorable risk:benefit balance. The current focus is on aromatase inhibitors, which appear to have more acceptable side effects in addition to being more efficacious in reducing breast cancer risk in high-risk women. The placebo-controlled phase III MAP.3 trial tested the AI exemestane in high-risk women and documented a 65% relative reduction in total and a 73% reduction in ER-positive breast cancers in the intervention compared to the placebo group. Toxicities centered around musculoskeletal side effects, but in the relatively short 35-month median follow-up period, these did not impair quality-of-life. A bone study nested within MAP.3 demonstrated significant decreases in bone mineral density (BMD) and in structural parameters of bone quality. The strengths and weaknesses of preventive exemestane as evaluated in the MAP.3 trial are discussed as are relevant areas for future consideration: influence of obesity, alternative dosing, and biomarker use in phase III prevention trials of aromatase inhibitors.

Associations of insulin-like growth factor and insulin-like growth factor binding protein-3 with mortality in women with breast cancer

Elevated circulating insulin-like growth factor-1 (IGF-1), a breast epithelial cell mitogen, is associated with breast cancer development. However, its association with breast cancer survival is not established. Circulating concentrations of IGF-1 are controlled via binding proteins, including IGF Binding Protein-3 (IGFBP-3), that may modulate the association of IGF-1 with breast-cancer outcomes. We measured IGF-1 and IGFBP-3 concentrations in serum from 600 women enrolled in the health, eating, activity, and lifestyle (HEAL) study, a multiethnic, prospective cohort study of women diagnosed with stage I-IIIA breast cancer. We evaluated the association between IGF-1 and IGFBP-3, and as a ratio, modeled using quintile cut-points, with risk of breast cancer-specific (n = 42 deaths) and all-cause mortality (n = 87 deaths) using Cox proportional hazards models. In models adjusted for body mass index, ethnicity, tamoxifen use at time of blood draw, treatment received at diagnosis and IGFBP-3, women in the highest quintile of IGF-1 level had an increased risk of all-cause mortality (Hazard Ratio (HR) = 3.10, 95% CI 1.21-7.93, p = 0.02), although no dose-response association was evident. The IGF-1/IGFBP-3 ratio, an indicator of free IGF-I levels, was significantly associated with increasing risk of all-cause mortality (HR = 2.83, 95% CI 1.25-6.36 p(trend) = 0.01, upper vs. lower quintile) in a fully adjusted model. In conclusion, high serum levels of IGF-1 and the IGF-1/IGFBP-3 ratio were associated with increased risk of all-cause mortality in women with breast cancer. These results need to be confirmed in larger breast cancer survivor cohorts.

Exemestane for breast cancer prevention: a critical shift?

The Mammary Prevention 3 (MAP.3) placebo-controlled randomized trial in 4,560 high-risk postmenopausal women showed a 65% reduction in invasive breast cancer with the use of exemestane at 35 months median follow-up. Few differences in adverse events were observed between the arms, suggesting a promising risk:benefit balance with exemestane for use in chemoprevention. Yet, the MAP.3 design and implementation raise concerns regarding limited data maturity and not prospectively including key bone-related and other toxicities as study end points. Exemestane for prevention is juxtaposed against selective estrogen receptor modulators and the other aromatase inhibitors. Additional issues for prevention, including the influence of obesity, alternative dosing, and biomarker use in phase III trials, are addressed.

SIGNIFICANCE

The recently completed MAP.3 trial of exemestane for breast cancer prevention offers a potential new standard for pharmaceutical risk reduction in high-risk postmenopausal women. In addition to describing key findings from the publication of MAP.3 and related trials, our review undertakes a detailed analysis of the strengths and weaknesses of MAP.3 as well as the implications for future prevention research.

Chemoprevention of Breast Cancer: The Paradox of Evidence versus Advocacy Inaction

Women who are at high risk of breast cancer can be offered chemoprevention. Chemoprevention strategies have expanded over the past decade and include selective receptor modulator inhibitors and aromatase inhibitors. Physicians are expected to provide individualized risk assessments to identify high risk women who may be eligible for chemoprevention. It is prudent that physicians utilize a shared decision approach when counseling high risk women about their preventive options. Barriers and misperceptions however exist with patient and physician acceptance of chemoprevention and continue to impede uptake of chemoprevention as a strategy to reduce breast cancer risk. Programs to increase awareness and elucidate the barriers are critical for women to engage in cancer prevention and promote chemoprevention adherence.

Oral low dose and topical tamoxifen for breast cancer prevention: modern approaches for an old drug

Tamoxifen is a drug that has been in worldwide use for the treatment of estrogen receptor (ER)-positive breast cancer for over 30 years; it has been used in both the metastatic and adjuvant settings. Tamoxifen's approval for breast cancer risk reduction dates back to 1998, after results from the Breast Cancer Prevention Trial, co-sponsored by the National Cancer Institute and the National Surgical Adjuvant Breast and Bowel Project, showed a 49% reduction in the incidence of invasive, ER-positive breast cancer in high-risk women. Despite these positive findings, however, the public's attitude toward breast cancer chemoprevention remains ambivalent, and the toxicities associated with tamoxifen, particularly endometrial cancer and thromboembolic events, have hampered the drug's uptake by high-risk women who should benefit from its preventive effects. Among the strategies to overcome such obstacles to preventive tamoxifen, two novel and potentially safer modes of delivery of this agent are discussed in this paper. Low-dose tamoxifen, expected to confer fewer adverse events, is being investigated in both clinical biomarker-based trials and observational studies. A series of systemic biomarkers (including lipid and insulin-like growth factor levels) and tissue biomarkers (including Ki-67) are known to be favorably affected by conventional tamoxifen dosing and have been shown to be modulated in a direction consistent with a putative anti-cancer effect. These findings suggest possible beneficial clinical preventive effects by low-dose tamoxifen regimens and they are supported by observational studies. An alternative approach is topical administration of active tamoxifen metabolites directly onto the breast, the site where the cancer is to be prevented. Avoidance of systemic administration is expected to reduce the distribution of drug to tissues susceptible to tamoxifen-induced toxicity. Clinical trials of topical tamoxifen with biological endpoints are still ongoing whereas pharmacokinetic studies have already shown that appropriate formulations of drug successfully penetrate the skin to reach breast tissue, where a preventive effect is sought.

Serum levels of IGF-I and BRCA penetrance: a case control study in breast cancer families

High serum levels of insulin-like growth factor I (IGF-I) are associated with an increased risk of sporadic breast cancer (BC). The aim of the present work is to evaluate the association between IGF-I and hereditary BC risk, using a case-control approach. The work represents an "ad interim" cross-sectional analysis of an ongoing study with a prospective design whose aim is to recruit a cohort of women belonging to high genetic risk families to test potential modulators of penetrance and prognosis. The odd of exposure to high serum IGF-I levels among women with a previous diagnosis of BC ("cases") was compared with the odd among unaffected "controls". The odds ratio (OR) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression, controlling for confounders. We analysed 308 women (209 cases and 99 controls) at high genetic risk of BC. The adjusted OR of BC for the upper tertile of serum IGF-I versus the lowest one was 3.5 (95%CI 1.4-8.8). Excluding from the analysis 64 women under current Tamoxifen or GnRH analogues treatment, the adjusted OR of BC became 3.7 (95%CI 1.4-9.9). The association became stronger restricting the analysis to the 161 women (97 cases and 64 controls) with a proven BRCA mutation. If confirmed by a prospective approach, the association between IGF-I and familial BC will open further options for reducing BC risk in susceptible women.

Lapatinib activity in premalignant lesions and HER-2-positive cancer of the breast in a randomized, placebo-controlled presurgical trial

Dual epidermal growth factor receptor (EGFR) and HER2 targeting with the tyrosine kinase inhibitor lapatinib is approved for treating advanced HER2-positive breast cancer and can prevent estrogen receptor (ER)-negative mammary tumors in HER2 transgenic mouse models. Ki-67 labeling index (LI) has prognostic and predictive value and can be used to screen drugs' therapeutic and preventive potential in a clinical model of short-term presurgical therapy of breast cancer. We conducted a randomized, placebo-controlled trial of lapatinib (1500 mg/d) administered orally for three weeks between biopsy and surgery in 60 women with HER-2-positive breast cancer to assess lapatinib biomarker (including the primary endpoint, Ki-67 LI) and clinical activity in invasive breast cancer, adjacent ductal intraepithelial neoplasia (DIN, which comprises ductal carcinoma in situ and atypical ductal hyperplasia), and distant ductal hyperplasia without atypia (DH). Ki-67 LI increased progressively in association with disease stage, increasing in the placebo arm, for example, by medians of 3% in DH to 20% in DIN to 30% in invasive cancer. Ki-67 LI in cancer tissue decreased by a mean (±SD) of 9.3% (±34.2) in the lapatinib arm and increased by 15.1% (±30.9) in the placebo arm (P = 0.008). Compared with placebo, lapatinib reduced Ki-67 significantly more in ER-negative tumors (by 34.8%; P = 0.01) but not significantly more in ER-positive tumors (by 12.3%; P = 0.2) and reduced Ki-67 more (nonsignificantly) in cytosol PTEN-overexpressing tumors (P = 0.057). The prevalence of DIN in post-treatment surgical specimens of both arms was similar (70%-76%), with a median Ki-67 of 15% (range, 5%-35%) on lapatinib versus 20% (5%-60%) on placebo (P = 0.067). The prevalence of DH also was similar in both arms (>90%), with a median Ki-67 of 1% (1%-7%) on lapatinib versus 3% (1%-5%) on placebo (P = 0.006). Other results of lapatinib versus placebo, respectively, were as follows: Median tumor diameter at surgery of 18 mm (11 mm-57 mm) versus 24 mm (10 mm-37 mm; P = 0.009); partial response of 13.6% versus 3.7%, stable disease of 59.1% versus 40.7%, and progression of 27.3% versus 55.6% (P-trend = 0.035). In conclusion, short-term lapatinib decreased cell proliferation in DIN, DH, and invasive HER-2-positive (especially ER-negative) breast cancer, thus providing the rationale for further clinical development of lapatinib for breast cancer prevention in high-risk patients, including those with HER-2-positive DIN.

KX-01, a novel Src kinase inhibitor directed toward the peptide substrate site, synergizes with tamoxifen in estrogen receptor α positive breast cancer

KX-01 is the first clinical Src inhibitor of the novel peptidomimetic class that targets the peptide substrate site of Src providing more specificity toward Src kinase. The present study was designed to evaluate the effects of KX-01 as a single agent and in combination with tamoxifen (TAM) on cell growth and apoptosis of ERα positive breast cancer in vitro and in vivo. Flow cytometry demonstrated that KX-01 induced cell cycle arrest in G2/M phase. Immunofluorescent staining for mitotic phase markers and TUNEL staining indicated that cells had arrested in the mitotic phase and mitotic arrested cells were undergoing apoptosis. KX-01 induced nuclear accumulation of cyclin B1, and activation of CDK1, MPM2, and Cdc25C that is required for progression past the G2/M checkpoint. Apoptosis resulted from activation of caspases 6, 7, 8, and 9. Combinational index analysis revealed that combinations of KX-01 with TAM resulted in synergistic growth inhibition of breast cancer cell lines. KX-01 combined with TAM resulted in decreased ERα phosphorylation at Src-regulated phosphorylation sites serines 118 and 167 that were associated with reduced ERα transcriptional activity. Orally administered KX-01 resulted in a dose dependent growth inhibition of MCF-7 tumor xenografts, and in combination with TAM exhibited synergistic growth inhibition. Immunohistochemical analysis revealed that combinational treatment reduced angiogenesis, and ERα signaling in tumors compared to either drug alone that may underlie the synergistic tumor growth inhibition. Combinations of KX-01 with endocrine therapy present a promising new strategy for clinical management of ERα positive breast cancer.

The management of ductal intraepithelial neoplasia (DIN): open controversies and guidelines of the Istituto Europeo di Oncologia (IEO), Milan, Italy

The management of ductal intraepithelial neoplasia (DIN) has substantially changed over the past 30 years, as its incidence has increased (from 2-3% to more than 20%), mainly due to the widespread use of mammography screening. This article describes not only the more widespread theoretical concepts on DIN but also the differences in the practical applications of the theory between different countries, different oncology specialists, and different cancer centers. Papers related to the international multicentre-randomized trials and retrospective studies were analyzed. We include articles and papers published between 1993 and 2010 related to patients with DIN, and abstracts and reports from MEDLINE and other sources were indentified. The standard of care for DIN consists of (a) breast conservative surgery (mastectomy is still indicated in large lesions--masses or microcalcifications--in about 30% of cases); (b) radiotherapy (RT) after conservative surgery, and (c) medical treatment in estrogen receptors-positive patients. However, most studies have shown significant differences between theory and practical application. Moreover, there are differences regarding (a) the indications of sentinel lymph node biopsy, (b) the definition and identification of low-risk DIN subgroups that can avoid RT and tamoxifen, and (c) the research into new alternative drugs in adjuvant medical therapy. A general agreement on the best management of DIN does not exist as yet. New large trials are needed in order to define the best management of DIN patients which is (in most respects) still complex and controversial.

Endometrial profile of tamoxifen and low-dose estradiol combination therapy

PURPOSE

Combination estrogen + progestin therapy has been associated with increased breast cancer risk in postmenopausal women. Selective estrogen receptor modulators (SERM) are potential alternatives to progestins, although the endometrial safety of estrogen + SERM co-therapies is not known. The goal of this study was to evaluate the endometrial profile of low-dose estradiol and the SERM tamoxifen alone and in combination.

EXPERIMENTAL DESIGN

Twenty-four postmenopausal female cynomolgus macaques were randomized by social group to receive placebo, low-dose micronized estradiol (E(2); 0.25 mg/1,800 kcal), the SERM tamoxifen (Tam; 20 mg/1,800 kcal), or E(2) + Tam for 4 months in a parallel-arm design.

RESULTS

Tamoxifen alone resulted in overlapping but distinct effects compared with E(2). Both E(2) and Tam increased uterine weight and endometrial thickness, whereas only E(2) increased endometrial proliferation. Morphologic effects were similar for Tam and E(2) + Tam, which both induced stromal fibrosis and cystic change. Tamoxifen inhibited E(2)-induced proliferation and expression of genes related to cell cycle progression while exhibiting mixed agonist and antagonist effects on gene markers of estrogen receptor activity. The gene expression profile for E(2) + Tam was distinct from either E(2) or Tam alone but dominated by the Tam effect for estrogen-regulated genes. Tam also attenuated E(2) effects on both vaginal maturation and cervical epithelial height.

CONCLUSIONS

These findings characterize a novel phenotype resulting from estrogen + SERM co-therapy. The predominance of Tam effects on endometrial proliferation, morphology, and transcriptional profiles suggests that endometrial risks for E(2) + Tam may be similar to Tam alone.

Stroma in breast development and disease

It is increasingly apparent that normal and malignant breast tissues require complex local and systemic stromal interactions for development and progression. During development, mammary cell fate specification and differentiation require highly regulated contextual signals derived from the stroma. Likewise, during breast carcinoma development, the tissue stroma can provide tumor suppressing and tumor-promoting environments that serve to regulate neoplastic growth of the epithelium. This review focuses on the role of the stroma as a mediator of normal mammary development, as well as a critical regulator of malignant conversion and progression in breast cancer. Recognition of the important role of the stroma during the progression of breast cancers leads to the possibility of new targets for treatment of the initial breast cancer lesion as well as prevention of recurrence.

Pharmacogenomics of Tamoxifen Therapy

Background: Tamoxifen is a standard endocrine therapy for the prevention and treatment of steroid hormone receptor–positive breast cancer.

Content: Tamoxifen requires enzymatic activation by cytochrome P450 (CYP) enzymes for the formation of active metabolites 4-hydroxytamoxifen and endoxifen. As compared with the parent drug, both metabolites have an approximately 100-fold greater affinity for the estrogen receptor and the ability to inhibit cell proliferation. The polymorphic CYP2D6 is the key enzyme in this biotransformation, and recent mechanistic, pharmacologic, and clinical evidence suggests that genetic variants and drug interaction by CYP2D6 inhibitors influence the plasma concentrations of active tamoxifen metabolites and the outcomes of tamoxifen-treated patients. In particular, nonfunctional (poor metabolizer) and severely impaired (intermediate metabolizer) CYP2D6 alleles are associated with higher recurrence rates.

Summary: Accordingly, CYP2D6 (cytochrome P450, family 2, subfamily D, polypeptide 6) genotyping before treatment to predict metabolizer status may open new avenues for individualizing endocrine treatment, with the maximum benefit being expected for extensive metabolizers. Moreover, strong CYP2D6 inhibitors such as the selective serotonin reuptake inhibitors paroxetine and fluoxetine, which are used to treat hot flashes, should be avoided because they severely impair formation of the active metabolites.

An open, randomised, multicentre, phase 3 trial comparing the efficacy of two tamoxifen schedules in preventing gynaecomastia induced by bicalutamide monotherapy in prostate cancer patients

BACKGROUND

Bicalutamide monotherapy is a valuable option for prostate cancer (PCa) patients who wish to avoid the consequences of androgen deprivation; however, this treatment induces gynaecomastia and mastalgia in most patients. Tamoxifen is safe and effective in preventing breast events induced by bicalutamide monotherapy without affecting antitumor activity, but possible interference between bicalutamide and tamoxifen remains a matter of concern. To reduce the exposure to tamoxifen, we considered the putative advantages of weekly administration.

OBJECTIVE

To compare the efficacy of two different schedules of tamoxifen in preventing breast events. Toxicity, prostate-specific antigen behaviour, and sexual-functioning scores were also evaluated.

DESIGN, SETTING, AND PARTICIPANTS

This was a noninferiority trial. From December 2003 to February 2006, 80 patients with localised/locally advanced or biochemically recurrent PCa who were also candidates for bicalutamide single therapy were randomised to receive two different schedules of tamoxifen: daily (n=41) and weekly (n=39). Median follow-up was 24.2 mo.

INTERVENTION

Daily bicalutamide (150 mg) plus daily tamoxifen 20mg continuously (daily group) or the same but with tamoxifen at 20mg weekly after the first 8 wk of daily treatment (weekly group). Three patients in the weekly group and one in the daily group were discontinued for adverse events.

MEASUREMENTS

For gynaecomastia, we used ultrasonography. For mastalgia and sexual functioning, we used questionnaires.

RESULTS AND LIMITATIONS

Gynaecomastia developed in 31.7% of patients in the daily group and in 74.4% of patients in the weekly group (p<0.0001), and it was more severe in patients who switched to weekly tamoxifen (p=0.001). Mastalgia occurred in 12.2% and 46.1% of patients, respectively (p=0.001). There were no major differences among treatment schedules relative to sexual functioning scores and incidence and severity of adverse events. No differences between groups in PSA behaviour and disease progression have been detected so far.

CONCLUSIONS

This study demonstrated that tamoxifen 20mg/wk is inferior to tamoxifen 20mg/d in preventing the incidence and severity of bicalutamide-induced breast events. The safety and efficacy of tamoxifen at the common daily dose of 20mg for the prophylaxis of bicalutamide-induced breast events were confirmed.