Re: tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study

New fluorobenzamidine exerts antitumor activity against breast cancer in mice via pro-apoptotic activity

BACKGROUND

Breast cancer is one of the leading causes of cancer-related morbidities. The present study aimed to evaluate the efficacy of bithiophene-fluorobenzamidine (BFB) against breast cancer induced by 7,12-dimethylbenz(a)anthracene (DMBA) in female Swiss mice and reveal the underlining mechanisms.

METHODS

The mice were randomly divided into five groups; control, BFB-treated group, DMBA-treated group, and the last two groups received DMBA then tamoxifen or BFB.

RESULTS

BFB reduced the tumor incidence by ~ 88% versus 30% after TAM. DMBA significantly increased the expression of CDK1 and HER2 and reduced the expression of p53, p21 (CDKN1A), ESR-α, and CAS3. BFB caused significant down-regulation of CDK1 and HER2 and upregulation of p53, p21, ESR-α, and CAS3. In the DMBA-treated mice, cancerous cells metastasized to several organs. This was prevented by the administration of BFB. The antimetastatic and proapoptotic activities were confirmed in MCF7 cells in vitro by the wound healing and annexin V assays, respectively. Kaplan-Meier analysis showed that the BFB increased survival. In the DMBA group, tumors showed invasive carcinoma of grade III with central necrosis, polymorphism, mitotic activity, and numerous newly formed ductules, and colloidal mucinous secretions within adenoid cysts. BFB administration restored the normal structure of the mammary glands.

CONCLUSION

Taken together, BFB has antitumor, pro-apoptotic, and anti-metastatic activities against breast cancer in mice and therefore, it merits further investigations.

Formulation Development for Transdermal Delivery of Raloxifene, a Chemoprophylactic Agent against Breast Cancer

Raloxifene (RLX) is a second-generation selective estrogen receptor modulator approved for the prevention of invasive breast cancer in women. Oral therapy of RLX requires daily intake and is associated with side effects that may lead to low adherence. We developed a weekly transdermal delivery system (TDS) for the sustained delivery of RLX to enhance the therapeutic effectiveness, increase adherence, and reduce side effects. We evaluated the weekly transdermal administration of RLX using passive permeation, chemical enhancers, physical enhancement techniques, and matrix- and reservoir-type systems, including polymeric gels. In vitro permeation studies were conducted using vertical Franz diffusion cells across dermatomed human skin or human epidermis. Oleic acid was selected as a chemical enhancer based on yielding the highest drug delivery amongst the various enhancers screened and was incorporated in the formulation of TDSs and polymeric gels. Based on in vitro results, both Eudragit- and colloidal silicon dioxide-based transdermal gels of RLX exceeded the target flux of 24 μg/cm²/day for 7 days. An infinite dose of these gels delivered 326.23 ± 107.58 µg/ cm² and 498.81 ± 14.26 µg/ cm² of RLX in 7 days, respectively, successfully exceeding the required target flux. These in vitro results confirm the potential of reservoir-based polymeric gels as a TDS for the weekly administration of RLX.

Optimization of thiazole analogues of resveratrol for induction of NAD(P)H:quinone reductase 1 (QR1)

NAD(P)H:quinone reductase 1 (QR1) belongs to a class of enzymes called cytoprotective enzymes. It exhibits its cancer protective activity mainly by inhibiting the formation of intracellular semiquinone radicals, and by generating α-tocopherolhydroquinone, which acts as a free radical scavenger. It is therefore believed that QR1 inducers can act as cancer chemopreventive agents. Resveratrol (1) is a naturally occurring stilbene derivative that requires a concentration of 21 μM to double QR1 activity (CD = 21 μM). The stilbene double bond of resveratrol was replaced with a thiadiazole ring and the phenols were eliminated to provide a more potent and selective derivative 2 (CD = 2.1 μM). Optimizing the substitution pattern of the two phenyl rings and the central heterocyclic linker led to a highly potent and selective QR1 inducer 9o with a CD value of 0.087 μM.

Fluvastatin reduces proliferation and increases apoptosis in women with high grade breast cancer

The purpose of this study is to determine the biologic impact of short-term lipophilic statin exposure on in situ and invasive breast cancer through paired tissue, blood and imaging-based biomarkers. A perioperative window trial of fluvastatin was conducted in women with a diagnosis of DCIS or stage 1 breast cancer. Patients were randomized to high dose (80 mg/day) or low dose (20 mg/day) fluvastatin for 3-6 weeks before surgery. Tissue (diagnostic core biopsy/final surgical specimen), blood, and magnetic resonance images were obtained before/after treatment. The primary endpoint was Ki-67 (proliferation) reduction. Secondary endpoints were change in cleaved caspase-3 (CC3, apoptosis), MRI tumor volume, and serum C-reactive protein (CRP, inflammation). Planned subgroup analyses compared disease grade, statin dose, and estrogen receptor status. Forty of 45 patients who enrolled completed the protocol; 29 had paired Ki-67 primary endpoint data. Proliferation of high grade tumors decreased by a median of 7.2% (P = 0.008), which was statistically greater than the 0.3% decrease for low grade tumors. Paired data for CC3 showed tumor apoptosis increased in 38%, remained stable in 41%, and decreased in 21% of subjects. More high grade tumors had an increase in apoptosis (60 vs. 13%; P = 0.015). Serum CRP did not change, but cholesterol levels were significantly lower post statin exposure (P < 0.001). Fluvastatin showed measurable biologic changes by reducing tumor proliferation and increasing apoptotic activity in high-grade, stage 0/1 breast cancer. Effects were only evident in high grade tumors. These results support further evaluation of statins as chemoprevention for ER-negative high grade breast cancers.

Drug Insight: breast cancer prevention and tissue-targeted hormone replacement therapy

The first-generation selective estrogen receptor modulator (SERM) tamoxifen has been the mainstream hormone therapy in breast cancer. Tamoxifen benefits all stages of the disease, but its use increases the risk of uterine cancer and thromboembolic events and it can only be administered for 5 years. Aromatase inhibitors are superior to tamoxifen at advanced stages of disease and as adjuvants; however, because they increase fractures, aromatase inhibitors are unlikely to be used to prevent disease. Raloxifene, a second-generation SERM, leads, like tamoxifen, to approximately 50% fewer cases of invasive breast cancer in high risk women, with a lower incidence of thromboembolic events. Several other SERMs are in development to improve tissue specificity, efficacy and tolerance. Raloxifene shows protection against vertebral fractures similar to bisphosphonates; however, no significant effect has been observed on nonvertebral fractures. Many SERMs are in development for prevention and treatment of osteoporosis. As breast cancer metastasizes early and advanced disease cannot be cured, prevention is essential. To avoid the concerns about the use of traditional hormone replacement therapy, dehydroepiandrosterone--a tissue-targeted precursor of sex steroid formation--offers hope of a physiological tissue-targeted hormone replacement that, combined with a SERM, would simultaneously prevent breast and uterine cancer.

Reduction in proliferation with six months of letrozole in women on hormone replacement therapy

The objective of this study was to determine if 6 months of the aromatase inhibitor letrozole, administered to postmenopausal women taking a stable dose of hormone replacement remedy, would be safe and would modulate biomarkers of breast cancer risk. The intent was to reduce the proliferation marker Ki-67 while maintaining adequate systemic levels of estradiol so as to avoid perimenopausal symptoms. Postmenopausal women at high risk for development of breast cancer and taking a stable dose of estrogen or estrogen plus progestin were screened by random periareolar fine needle aspiration (RPFNA). To be eligible, the acquired breast epithelial cells had to be characterized as cytologic atypia or borderline atypia with > or =1,000 epithelial cells on the cytomorphology slide; plus > or =500 epithelial cells on a slide processed for Ki-67 immunocytochemistry. Forty-two women were enrolled in the one arm study and received 2.5 mg letrozole per day for 6 months, followed by repeat assessment of biomarkers. Ki-67 was reduced by a median relative value of 66%. There was no significant change in breast cell cytomorphology; ER weighted index score; serum estradiol, testosterone, or IGF-1:IGFBP-3 ratio; mammographic breast density, or frequency or severity of perimenopausal symptoms. Given the dramatic reduction in proliferation, the effect of letrozole on risk and response biomarkers should be explored further in a randomized, placebo-controlled Phase IIB breast cancer chemoprevention trial.

Healthy Women with a Family History of Breast Cancer: Impact of a Tailored Genetic Counseling Intervention on Risk Perception, Knowledge, and Menopausal Therapy Decision Making

BACKGROUND

Women with a family history of breast cancer have several menopausal therapy options, including tamoxifen, hormone therapy (HT), alternative medications, or no treatment. This complex decision should be based on each woman's risk to develop breast cancer, menopausal symptoms, preferences, and risks for other conditions. The authors determined the effects of a personalized risk assessment and genetic counseling intervention on knowledge, risk perception, and decision making in a group of healthy women who had a first-degree relative with breast cancer.

METHODS

Forty-eight cancer-free menopausal women age > or =40 years who had at least one first-degree relative with breast cancer were randomized to a genetic counseling intervention or control. Intervention participants were given a personalized risk assessment for breast cancer, heart disease, osteoporosis, and uterine cancer based on family history and personal health data. Knowledge, risk perception, and medication usage were measured at baseline, 1 month, and 6 months.

RESULTS

Knowledge was higher in the intervention group at both follow-up time points postintervention. Perceived risk for developing breast cancer was significantly lower and more accurate in the intervention group at 1 and 6 months postintervention than at baseline, as was perceived risk of developing heart disease. Although the counseling intervention did affect both knowledge and risk perception, overall, both groups were reluctant to take any form of menopausal therapy.

CONCLUSIONS

A personalized risk assessment and genetic counseling intervention improves patient knowledge and risk perception; however, it is unclear that the intervention influenced menopausal treatment decisions.

Breast Cancer Risk Assessment and Prevention: A Framework for Shared Decision-Making Consultations

Options for breast cancer prevention, used in combination with screening and surveillance, include lifestyle modifications, chemoprevention with tamoxifen, and prophylactic surgery. Preventive health decisions are often preference driven: patients typically must choose whether to initiate effective treatments that hold the possibility of side effects that can negatively impact quality of life. This situation demands that patients be well informed and have a full understanding of the risks associated with each option. Investigators have developed a comprehensive decision-making framework designed to support breast cancer prevention consultations within a shared decision-making setting. The framework integrates predictive information from current risk models within the context of a woman's general health to appropriately frame breast cancer risk management consultations and outlines the application of available treatments and emerging biomarker information to individual patient decisions. Using an evidence-based approach, specialized risk-benefit projections can be provided in the clinical setting. A more comprehensive individualized risk profile allows for tailored medical management plans and can better prepare patients to make informed decisions. The framework is intended to encourage a shared decision-making approach to prevention consultations, a method for researchers to increase accrual to trials, and to more quickly incorporate new findings into the routine of practice.

Nipple aspiration and ductal lavage in women with a germline BRCA1 or BRCA2 mutation

Introduction

The aim of this study was to collect serial samples of nipple aspirate (NA) and ductal lavage (DL) fluid from women with germline BRCA1/2 mutations in order to create a biorepository for use in identifying biomarkers of breast cancer risk.

Methods

Between March 2003 and February 2005, 52 women with germline BRCA1 or BRCA2 mutations (median age 43 years, range 27 to 65 years) were scheduled for six-monthly NA, DL and venesection. DL was attempted for all NA fluid-yielding (FY) and any non-FY ducts that could be located at each visit.

Results

Twenty-seven (52%) women were postmenopausal, predominantly (19/27) from risk reducing bilateral salpingo-oophorectomy (BSO). FY ducts were identified in 60% of all women, 76% of premenopausal women versus 44% of postmenopausal (P = 0.026). Eighty-five percent of women had successful DL. Success was most likely in women with FY ducts (FY 94% versus non-FY 71% (P = 0.049). DL samples were more likely to be cellular if collected from FY ducts (FY 68% versus non-FY 43%; P = 0.037). Total cell counts were associated with FY status (FY median cell count 30,996, range 0 to >1,000,000 versus non-FY median cell count 0, range 0 to 173,577; P = 0.002). Four women (8%) had ducts with severe atypia with or without additional ducts with mild epithelial atypia; seven others had ducts with mild atypia alone (11/52 (21%) in total). Median total cell count was greater from ducts with atypia (105,870, range 1920 to >1,000,000) than those with no atypia (174, 0 to >1,000,000; P ≤ 0.001).

Conclusion

It is feasible to collect serial NA and DL samples from women at high genetic risk of breast cancer, and we are creating a unique, prospective collection of ductal samples that have the potential to be used for discovery of biomarkers of breast cancer risk and evaluate the ongoing effects of risk reducing BSO. DL cellular atypia was not predictive of a current breast cancer and longer follow up is needed to determine whether atypia is an additional marker of future breast cancer risk in this population already at high genetic risk of breast cancer.

Ductal lavage for breast cancer risk assessment

Ductal lavage is a minimally-invasive procedure that permits sampling of breast ductal fluids for cytopathologic analysis. The technique is performed with topical anesthesia and involves cannulation of any fluid-yielding nipple orifice with a specially-designed catheter for lavage and aspiration of the ductal system. The procedure is used for women who have clinical evidence of increased breast cancer risk; if atypia is detected, it may strengthen a woman's interest in committing to a risk-reducing strategy or a chemoprevention trial. The technology also is being used as a tool in ongoing translational research studies.

Ductal lavage in the high-risk patient

BACKGROUND

[corrected] This analysis was conducted in a single-surgeon clinical practice to evaluate the utility and practicality of performing ductal lavage in a population determined to be at high risk for breast cancer.

METHODS

One hundred twenty patients with negative mammograms and/or negative breast examinations had nipple aspiration and ductal lavage performed by a single surgeon. All were at high risk either according to Gail risk score, a previous breast carcinoma, or nipple discharge.

RESULTS

One hundred twenty patients underwent nipple aspiration. Thirty-two did not undergo lavage: 29 had no fluid, and 3 had unsuccessful cannulation. Eighty-eight underwent lavage: 15 had insufficient epithelial content, 51 had benign cytology, and 22 had abnormal cells. Of the 22, 20 had mild atypia, 1 had marked atypia, and 1 had malignant cells.

CONCLUSIONS

Ductal lavage can be done in a surgical practice and can stratify risk for the individual patient. This is important to both patient and surgeon in formulating a treatment plan based on objective cytologic criteria.

Nipple Aspirate Fluid Cytology and the Gail Model for Breast Cancer Risk Assessment in a Screening Population

BACKGROUND

Recent guidelines suggest that chemoprevention with tamoxifen may be appropriate for women who have a 5-year risk of breast cancer greater than 1.66% calculated using the Gail model.

OBJECTIVES

To determine whether nipple aspirate fluid (NAF) cytology combined with the Gail model provides breast cancer risk assessment that is superior to either method alone.

METHODS

Prospective observational cohort of 6,904 asymptomatic women. Breast cancer cases were identified through follow-up with the women and linkage to cancer registries. We used proportional hazards modeling to recalculate the coefficients for the predictor variables used in the Gail model. NAF cytology was added to create a second model. The two models were compared using the concordance statistic (c-statistic).

RESULTS

During 14.6 years of follow-up, 400 women were diagnosed with breast cancer. There were 940 (14%) women with hyperplasia and 109 (1.6%) women with atypical hyperplasia found in NAF. Adding NAF cytology results to the Gail model significantly improved the model fit (P < 0.0001). The c-statistic for the Gail model was 0.62, indicating only modest discriminatory accuracy. Adding NAF cytology to the model increased the c-statistic to 0.64. NAF cytology results had the largest effect on discriminatory accuracy among women in the upper third of Gail model risk. The relative incidence for the highest quintile of risk score compared with the lowest quintile was 7.2 for the Gail model and 8.0 for the model including NAF cytology.

CONCLUSION

NAF cytology has the potential to improve prediction models of breast cancer incidence, particularly for high-risk women.

Evaluation of Breast Cancer Risk Assessment Techniques: A Cost-effectiveness Analysis

Objective: Assess the effectiveness and cost-effectiveness of using biomarkers and risk assessment tools to stratify women for breast cancer preventive interventions.

Methods: A Markov model was developed to compare risk management strategies for high-risk women considering chemoprevention. Annual screening is compared to the use of chemoprevention for all women and the use of risk assessment technologies to stratify patients for chemoprevention. The biomarker atypia was used to stratify women by risk. Random fine-needle aspiration (rFNA) and ductal lavage (DL) were evaluated and compared as the risk assessment tools used to discover atypia. Sensitivity analyses explore assumptions regarding the prognostic and predictive characteristics of atypia, both the relative breast cancer risk and benefit from chemoprevention women with atypia incur.

Results: Risk assessment strategies using rFNA or DL in combination with chemoprevention are found to be cost-effective (&lt;$50,000 per life year saved) in high-risk groups under most scenarios. Both strategies were more effective and less costly in younger cohorts. Effectiveness of the risk assessment strategies increased when higher risk and increased benefit from chemoprevention were associated with atypia. Within the scenarios tested, rFNA is less costly than DL.

Conclusion: rFNA and DL appear to be cost-effective in high-risk women, assuming women with detected atypia choose tamoxifen. The tools are largely effective for women who are not motivated to take tamoxifen but would be if atypia were found. As biomarker risk assessment tools better predict the risk of breast cancer and or benefit of interventions, their cost-effectiveness increases.

The role of ductal lavage in the management of women at high risk for breast carcinoma

Ductal lavage (DL) is a recently introduced technique for nonsurgical breast epithelial sampling of asymptomatic high-risk women. It is based on exfoliative cytology of duct epithelial cells, obtained by cannulation and lavage of ducts that produce nipple fluid after breast massage and nipple aspiration. DL provides information similar to that obtained by cytologic examination of nipple aspiration fluid and random periareolar fine needle aspiration. Women who demonstrate cytologic atypia on these tests can be assumed to be at higher risk for breast cancer and may benefit from prophylactic medication. DL promises to provide more reproducible sampling of the same area of the breast, as opposed to methods of random sampling, such as random fine needle aspiration, but the degree of reproducibility remains to be demonstrated. If reproducibility is greater than with random periareolar fine needle aspiration, DL may represent an important advance in the design of phase II chemoprevention trials, particularly because it also provides another source of material for judging response to prevention agents (ie, the protein component of nipple aspiration fluid), which can be analyzed for levels of hormones, specific proteins, and protein profiles obtained with proteomics. Early data do not suggest that DL is an effective screening tool for breast cancer on the basis of cytologic interpretation of DL samples, although this may change if effective molecular markers are validated for cancer detection in women at high risk.

Breast Cancer from a Public Health Perspective

By 2010, the majority of approximately 1.5 million annual new cases of breast cancer will be diagnosed in women in countries with limited resources. Public health approaches to medical problems emphasize the importance of practical, limited toxicity and very inexpensive interventions. While clinical trials in Western countries are testing the concept of breast cancer prevention, they are not defining useful public health approaches. Early detection of breast cancer using mammography, while effective, is a high-technology, expensive approach. Adjuvant systemic and radiation therapies are increasingly expensive; careful consideration of efficacy and cost-efficacy data appear warranted. Public health perspectives thus suggest that many current "standard" approaches to breast cancer in Western countries cannot help the majority of women in the world.

Current comprehensive assessment and management of women at increased risk for breast cancer

The potential for reducing the risk of breast cancer through selective estrogen receptor modulators, aromatase inhibitors, and surgery has generated interest in the use of quantitative models of risk assessment. With the addition of ductal lavage cytology to traditional epidemiologic risk factors, a discovery of cellular atypia can result in refinement of assigned risk values, while simultaneously optimizing patient selection for selective estrogen receptor modulators utilization. In view of increasing complexity in this arena, a Risk Assessment Working Group was formed to outline management strategies for the patient at an elevated risk for the development of breast cancer. No longer a statistical exercise, quantitative risk assessment is part of basic breast care and comprehensive management includes a discussion of the following: ductal lavage for improved risk stratification, multiple options for risk reduction, and high risk surveillance strategies that might incorporate investigational imaging protocols.

Applying the neoadjuvant paradigm to ductal carcinoma in situ

Local treatment options for ductal carcinoma in situ (DCIS) are virtually identical to those for early invasive breast cancer, despite the fact that the survival from this condition is much higher. Our ability to more appropriately tailor therapy for DCIS is hampered by a lack of understanding of the natural history of DCIS, our limited ability to predict the rate of progression to invasive cancer and the response to therapy, and the absence of tools to follow patients who have not had invasive treatments. Neoadjuvant therapy, which has been proven to be both safe and effective in tailoring treatments for invasive cancer, could be ideally suited to DCIS. However, neoadjuvant therapy requires that doctors and patients delay surgical treatment that has known benefits. In order to successfully introduce this approach into clinical practice, risk assessment and decision support tools will be needed to help physicians and patients feel comfortable that they are not being exposed to unnecessary or excessive risk. In addition, we need better imaging to track extent and progression of disease. Among the possible benefits of the neoadjuvant approach, we may discover that many lesions are responsive and some even reversible, leaving us with treatments that might be tailored to biology and with important clues for breast cancer prevention in high-risk women.

Acceptance of tamoxifen chemoprevention by physicians and women at risk

BACKGROUND

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 trial, tamoxifen was shown to reduce breast carcinoma risk by 49% in high-risk women. The purpose of the current study was to identify factors associated with being offered, and accepting, tamoxifen chemoprevention.

METHODS

The records of 219 women who sought risk evaluation after the publication of the NSABP P-1 trial between September 1998 and October 2002 were reviewed. Risk was calculated using the model of either Gail et al. or Claus et al. The impact of individual risk factors on the offering and acceptance of tamoxifen was compared using the Fisher exact test and logistic regression analysis.

RESULTS

Tamoxifen was offered to 137 women (63%) in the current study. The magnitude of Gail risk, age, menopausal status, hysterectomy, and history of lobular carcinoma in situ (LCIS) or atypical hyperplasia (AH) were all found to be significant predictors of a patient being offered tamoxifen. On multivariate analysis, only a history of AH or LCIS and hysterectomy were found to be significant, with odds ratios of 20.3 and 3.4, respectively. Fifty-seven of the women who were offered tamoxifen (42%) took the drug. Only a history of LCIS or AH and older age were found to be predictive of tamoxifen acceptance.

CONCLUSIONS

In the current study, risk due to AH or LCIS was found to be the main predictor of being offered and accepting tamoxifen chemoprevention.

Atypia in the assessment of breast cancer risk: Implications for management

Proliferative disease accounts for as much as one-third of all biopsies for benign disease and 5-10% of proliferative lesions show atypia ductal or lobular hyperplasia. Nearly 40% of women with a family history of breast cancer and atypical hyperplasia subsequently develop breast cancer. A quantitative model developed by Gail and colleagues estimates the probability of developing breast cancer over time. Risk factors in the model include current age, ages at menarche and first live birth, number of previous biopsies, the presence of cellular atypia, and the number of first-degree relatives with breast cancer. Atypical hyperplasia approximately doubles the risk of developing invasive breast cancer within any quantitative risk profile. Ductal lavage provides a minimally invasive method of collecting breast epithelial cells. The procedure opens the possibility of repeatable tracking of breast cytology over time, but its role as a risk assessment tool remains to be fully defined.

Advances in breast cancer detection and management

Breast cancer detection and management have undergone dramatic changes over the past three decades. Women are increasingly diagnosed with early stage disease, and leaving them with breast conserving options versus mastectomy. Furthermore, advances in the chemoprevention arena offer the promise of reduced overall breast cancer burden in the future.