Breast Cancer In High-risk Women Research Articles

Bioactivation of the Selective Estrogen Receptor Modulator Acolbifene to Quinone Methides

Although approved for the treatment of hormone-dependent breast cancer as well as for the prevention of breast cancer in high-risk women, the selective estrogen receptor modulator (SERM) tamoxifen has been associated with an increased risk of endometrial cancer in women. With an understanding of the potential carcinogenic mechanisms of these compounds, SERMs could in principle be designed or selected for use that avoids these problems. Acolbifene (EM-652) is a fourth-generation SERM and the active form of the ester prodrug EM-800. As a pure antagonist of breast tumor development and growth, acolbifene does not stimulate endometrial tissue. However, acolbifene was found in this investigation to form two kinds of quinone methides, either through chemical or through enzymatic oxidation. One was a classical acolbifene quinone methide, which was formed by oxidation at the C-17 methyl group, and the other was a diquinone methide involving the oxidation of two phenol groups. The half-life of the classical quinone methide was determined to be 32 +/- 0.4 s at physiological pH and temperature. The quinone methides reacted with glutathione (GSH) to form five mono-GSH conjugates and five di-GSH conjugates. The majority of GSH conjugates resulted from reaction of the classical acolbifene quinone methide with GSH. Incubations of acolbifene with GSH and either tyrosinase or human and rat liver microsomes also produced acolbifene quinone methide-GSH conjugates. In addition to reaction with GSH, the classical acolbifene quinone methide was also shown to react with deoxynucleosides. One of the major deoxynucleoside adducts was identified as the deoxyadenosine adduct resulting from reaction of the classical acolbifene quinone methide with the exocyclic amino group of adenine. Acolbifene could also induce DNA damage in the S30 breast cancer cell line. These data imply that the classical electrophilic acolbifene quinone methide might contribute to the potential toxicity of acolbifene.

Magnetic resonance imaging was more sensitive than mammography for detecting breast cancer in high-risk women

Source Citation Kriege M, Brekelmans CT, Boetes C, et al. Efficacy of MRI and mammography for breast-cancer screening in women with a familial or genetic predisposition. N Engl J Med. 2004;351:427-...

Prophylactic bilateral mastectomy for breast cancer prevention.

Prophylactic bilateral mastectomy, or preventive removal of the breasts, is an option for women who are at increased risk of developing breast cancer. Among the highest risk groups are those women with a significant family history of breast cancer and those with a known genetic predisposition to the disease. There are many issues surrounding prophylactic mastectomy. Recent research has demonstrated that prophylactic mastectomy may be effective in preventing breast cancer in high-risk women, as well as those with a known BRCA1/2 mutation. The limited research that has been done on the psychosocial implications of the preventive surgery suggests that prophylactic mastectomy may be effective in reducing distress levels in high-risk women and that most women who have had the surgery do not experience psychosocial difficulties. Overall, women who have had prophylactic mastectomy are satisfied with their decision to have the preventive surgery. However, women who choose prophylactic mastectomy may differ compared with those who do not. The results may not be generalizable to all high-risk women. Counseling of high-risk women, specifically those with a BRCA1 or BRCA2 mutation, should include a discussion of prophylactic mastectomy, including the medical and psychosocial risks and benefits.

Impact of screening for breast cancer in high-risk women on health-related quality of life.

The effectiveness of intensive surveillance in women at high risk for breast cancer due to a familial or genetic predisposition is uncertain and is currently being evaluated in a Dutch magnetic resonance imaging (MRI) screening (MRISC) study, in which annual imaging consists of mammography and MRI. Unfavourable side effects on health-related quality of life may arise from this screening process. We examined the short-term effects of screening for breast cancer in high-risk women on generic health-related quality of life and distress. A total of 519 participants in the MRISC study were asked to complete generic health-status questionnaires (SF-36, EQ-5D) as well as additional questionnaires for distress and items relating to breast cancer screening, at three different time points around screening. The study population showed significantly better generic health-related quality of life scores compared to age-/sex-adjusted reference scores from the general population. Neither generic health-related quality of life scores nor distress scores among the study sample (n=334) showed significant changes over time. The impact of the screening process on generic health status did not differ between risk categories. Relatively more women reported mammography as quite to very painful (30.1%) compared to MRI. Anxiety was experienced by 37% of the women undergoing MRI. We conclude that screening for breast cancer in high-risk women does not have an unfavourable impact on short-term generic health-related quality of life and general distress. In this study, high-risk women who opted for regular breast cancer screening had a better health status than women from the general population.

Advances in Screening, Diagnosis, and Treatment of Breast Cancer

Advances in Screening, Diagnosis, and Treatment of Breast Cancer

Endocrine prevention of breast cancer using selective oestrogen receptor modulators (SORMs)

Breast cancer remains the most common malignancy in women worldwide. Oestrogen levels appear to be associated with an increased risk for the development of breast cancer. The Early Breast Cancer Trialists' Cooperative Group reported in a 1998 meta-analysis of 37000 breast cancer patients in 55 randomized adjuvant trials that tamoxifen, a selective oestrogen receptor modulator, reduced the incidence of contralateral breast cancers by 47% at 5 years. Tamoxifen has been shown in numerous prevention studies to decrease the incidence of breast cancer in high-risk women. Overall, the tamoxifen prevention trials showed a 38% reduction in the incidence of breast cancer (95% CI 28-46; P<0.0001). In the largest risk-reduction trial, the Breast Cancer Prevention Trial conducted by the National Surgical Adjuvant Breast and Bowel Project, tamoxifen reduced the risk of invasive breast cancer by 49% (two-sided P<0.00001), and non-invasive breast cancer by 50% (P<0.002). The occurrence of oestrogen receptor-(OR)-positive tumours decreased by 69%. Tamoxifen reduces the risk of developing oestrogen receptor-positive tumours, but OR-negative tumours are not affected. Rare but life-threatening side-effects of tamoxifen include endometrial carcinoma, thromboembolic events and cerebrovascular events. Less serious side-effects include cataracts, vasomotor instability, nausea and vaginal discharge. Raloxifene, a second-generation selective oestrogen receptor modulator, is approved for treatment of osteoporosis in post-menopausal women in the USA but it is not currently approved for breast cancer prevention outside of a clinical trial. Prevention studies involving raloxifene and aromatase inhibitors are currently being conducted.

Changing role of the oestrogen receptor in the life and death of breast cancer cells

The oestrogen receptor (ER) has proven to be an extraordinarily successful target for breast cancer treatment and prevention. The clinical use of tamoxifen, a nonsteroidal antioestrogen, demonstrated (1) that the strategic use of adjuvant tamoxifen in ER-positive patients could save lives and (2) that a selective ER modulator (SERM) could reduce the incidence of breast cancer in high-risk women. The ER is now the target for new and safer therapies such as the aromatase inhibitors and the pure antioestrogens that either block oestrogen synthesis or destroy the ER. However, the use of raloxifene, a SERM to prevent osteoporosis with the potential to prevent breast cancer has introduced a new dimension into preventive oncology. The widespread use of endocrine modulators (SERMs, aromatase inhibitors, and pure antioestrogens) raised the question of drug resistance. It is now clear that endocrine resistance can evolve through stages. Once a breast tumour becomes resistant to SERMs, the growth is stimulated by either the SERM or oestrogen. This is why an aromatase inhibitor is effective following SERM resistance and withdrawal. However, the extended use of repeated endocrine therapies now supersensitized the cells to oestrogen that causes apoptosis through the ER. We suggest that future clinical treatment strategies incorporate an ‘oestrogen purge’ to both enhance the actions of chemotherapy or completely reverse endocrine resistance and restore endocrine sensitivity. These new data build on the idea that breast cancer can be controlled as a chronic disease and will permit patients to live long and productive lives during targeted maintenance treatment.

Oestrogens, Oestrogen Receptors and Breast Cancer

Tamoxifen has been the endocrine treatment of choice for all stages of oestrogen receptor positive breast cancer for 20 years and the first chemical therapeutic to be tested to reduce the incidence of breast cancer in high-risk women. It is now clear that the oestrogen receptor is proving to be an invaluable target for the treatment and chemoprevention of breast cancer. The success of tamoxifen clinically can be quantitated: 400 000 women are alive today because of the application of 5 years of adjuvant tamoxifen therapy in node-positive and node-negative breast cancer. This advance has resulted in vigorous efforts to reduce side-effects and to improve objective response rates by the rapid application of laboratory principles. Tamoxifen is known to have a mixture of oestrogen-like and anti-oestrogen actions so it is reasoned that completely anti-oestrogenic agents would enhance treatment response rates while lowering the incidence of oestrogen-like side-effects such as endometrial cancer and blood clots. A new pure anti-oestrogen, fulvestrant, that destroys the oestrogen receptor, is available after drug resistance to tamoxifen develops. The group of drugs known as aromatase inhibitors block the production of oestrogens from androstenedione and testosterone in the body fat of postmenopausal women. New agents such as anastrozole, exemestane, and letrozole have shown promise as new treatment modalities for advanced breast cancer. Most importantly, the successful testing of anastrozole as an adjuvant treatment for breast cancer has enhanced enthusiasm for the evaluation of aromatase inhibitors and selective oestrogen receptor modulators (SERMs) to be tested as chemopreventives. SERMs express anti-oestrogenic actions in the breast but oestrogen-like actions in bone and lower circulating cholesterol. This insight not only allowed the safe application of tamoxifen to well high-risk women to test the worth of an ‘anti-oestrogen’ to prevent breast cancer, but also caused a paradigm shift in the strategy of chemoprevention. The question was posed that if, tamoxifen prevents breast cancer but an added benefit is the maintenance of bone density, why not develop a drug to prevent osteoporosis or atherosclerosis that prevents breast cancer in the general population as a beneficial side-effect? Raloxifene is the result of this new strategy to seek multifunctional medicines for women's health. Raloxifene is currently available for the treatment and prevention of osteoporosis but is being tested in high-risk postmenopausal women for the prevention of breast cancer against tamoxifen in the study of tamoxifen and raloxifene (STAR trial) and for the prevention of coronary heart disease (CHD) in a placebo-controlled trial in women at high risk for CHD called raloxifene use for the heart (RUTH).

Systemic treatments for women with breast cancer: outcome with relation to screening for the disease

Early detection and proper care of breast cancer are currently the best available approaches to the treatment of patients with the disease. In countries with a breast cancer screening programme, there has been a demonstrated reduction in breast cancer-related mortality. Such reduction has also been observed in Switzerland, a country in which no national programme of screening is available. Although there is no doubt that early diagnosis might have had a major role in reducing breast cancer mortality the magnitude of this effect is unknown. Research with tailored approaches on alternative imaging for early detection of breast cancer in high-risk women and on treatments offered according to proper criteria of responsiveness to therapies is warranted.

RESPONSE: Re: Italian Randomized Trial Among Women With Hysterectomy: Tamoxifen and Hormone-Dependent Breast Cancer in High-Risk Women

RESPONSE: Re: Italian Randomized Trial Among Women With Hysterectomy: Tamoxifen and Hormone-Dependent Breast Cancer in High-Risk Women

Re: Italian Randomized Trial Among Women With Hysterectomy: Tamoxifen and Hormone-Dependent Breast Cancer in High-Risk Women

Re: Italian Randomized Trial Among Women With Hysterectomy: Tamoxifen and Hormone-Dependent Breast Cancer in High-Risk Women

Ductal Lavage Screening for Breast Cancer in High-Risk Women in the Gynecologist's Office

Ductal Lavage Screening for Breast Cancer in High-Risk Women in the Gynecologist's Office

Ductal lavage screening for breast cancer in high-risk women in the gynecologist’s office

Ductal lavage screening for breast cancer in high-risk women in the gynecologist’s office

Cancer chemoprevention drug targets.

Cancer chemoprevention is a new approach in the management of cancer. Traditional cytotoxic chemotherapeutic approaches cannot cure most advanced solid malignancies. Chemoprevention can be defined as the use of non-cytotoxic drugs and natural agents to block the progression to invasive cancer. Chemoprevention can either prevent DNA damage that initiates the neoplastic transformation process or reverses the progression of pre-invasive lesions. Epidemiological observations, experimental evidence from animal carcinogenesis models, knock-out models, cancer cell lines and clinical trials have shown the efficacy of this approach. Recent advances in our understanding of carcinogenesis have led to the synthesis of new drugs that target specific receptors. Non-steroidal anti-inflammatory drugs target the prostaglandin pathway. The identification of the role of cyclooxygenase-2 in epithelial carcinogenesis led to the synthesis of selective cyclooxygenase-2 inhibitors (Celecoxib). Celecoxib was subsequently approved for the prevention of colon polyps in familial adenomatous polyposis after the completion of a randomized clinical trial. The large chemoprevention clinical trial with the selective estrogen receptor modulator, tamoxifen, showed the benefit of tamoxifen in the prevention of breast cancer in high-risk women. Retinoids and rexinoids target the retinoid receptors and have a role in chemoprevention of aerodigestive, hepatic and cervical neoplasia. Selenium, an inhibitor of the glutathione peroxidase system, is being tested in the chemoprevention of prostate cancer and lung cancer. The different isoforms of vitamin E (tocopherols) may be chemopreventive. Recent evidence indicates that gamma-tocopherol may be a more powerful chemopreventive than the alpha-tocopherol. The review details the rationale, experimental and clinical evidence and the drug targets of the chemopreventive agents that are currently in various phases of clinical development.

Has tamoxifen had its day?

Tamoxifen is probably the most important drug in the history of the management of breast cancer and its development is a tribute to cross talk between laboratory scientists and clinical investigators. Its use as adjuvant therapy has led to a decrease of 20-30% in age-adjusted cause-specific mortality in the developed world and it is approved in the USA for the chemoprevention of breast cancer in high-risk women. The recent ATAC and IBIS trials have challenged the supremacy of tamoxifen. The present paper is a personal view of the implications for the future use of this drug in competition with the oral aromatase inhibitors. In the opinion of the author tamoxifen will probably remain the mainstay for adjuvant therapy of postmenopausal women with hormone-responsive disease, but maturation of the ATAC data may allow a choice in selected cases. Anastrozole looks like a competitor for the future but we may have to wait another 10 years to find out.

Raloxifene reduces breast cancer in high-risk women

Raloxifene reduces breast cancer in high-risk women

The MORE Trial: Multiple Outcomes for Raloxifene Evaluation

Breast cancer is a common disease in the United States and Europe and is therefore a major target for prevention strategies. Estrogen plays a central role in its pathogenesis, and treatment with estrogen deprivation has long been recognized to be an effective therapy. Tamoxifen is the first selective estrogen receptor modulator (SERM) to be widely used for the treatment of breast cancer and has been demonstrated to reduce the risk of breast cancer in high-risk women. Raloxifene is a second-generation SERM that has estrogenic effects on bone and lipid metabolism, and antiestrogenic effects on breast tissue. Unlike tamoxifen, raloxifene displays antiestrogenic effects on the endometrium and may serve as a safer alternative to tamoxifen in the prevention setting. The MORE trial is a multicenter randomized placebo-controlled trial designed to determine whether 3 years of raloxifene reduces the risk of fracture in postmenopausal women with osteoporosis. As a secondary end point of the trial, raloxifene was shown to reduce the risk of both in situ and invasive breast cancer by 65% (RR = 0.35; 95% CI = 0.21-0.58; P < 0.001). The benefits were most significant in women who developed estrogen receptor (ER)-positive cancers, with a relative risk of 0.10 (95% CI = 0.04-0.24). This reduced incidence of breast cancer may be due to an anticarcinogenic effect or to a slowing of growth of occult ER-positive cancer, with a shift to the right in the time-to-cancer curve. A second large-scale prevention trial in breast cancer comparing tamoxifen to raloxifene is presently enrolling cancer-free, but high-risk postmenopausal women (the STAR trial). Future directions include combined estrogen blockade of the breast by the addition of an aromatase inhibitor to a SERM. New trial designs, including those based on biochemical changes at the tissue level, will be required to allow future progress in this field with adequate rapidity.

The past, present, and future of selective estrogen receptor modulation.

The recognition of selective estrogen receptor modulation in the mid-1980s provided a unique opportunity to develop multifunctional drugs. Tamoxifen, the first selective estrogen receptor modulator (SERM), is the first antiestrogen to be tested successfully for the prevention of breast cancer in high-risk women. However, the recognition that SERMs maintain bone density and lower circulating cholesterol suggested that the prevention of osteoporosis and coronary heart disease would be beneficial side effects of tamoxifen treatment. This hypothesis has not been pursued in clinical trial, but an alternate hypothesis, that SERMs could be developed to prevent osteoporosis and potentially reduce the risk of breast cancer, has been pursued with raloxifene. Current molecule modeling of the SERM-ER complex has identified the reason for the promiscuous estrogen-like actions of tamoxifen compared with raloxifene. Future studies of the signal transduction pathways of the ER alpha (alpha)- and beta (beta)-SERM complexes hold the promise of new drug discoveries and a menu of preventive medicine in clinical practice.

Use of SERMs for the adjuvant therapy of early-stage breast cancer.

Tamoxifen was the first in a class of drugs now commonly referred to as selective estrogen receptor modulators or SERMs. SERMs exhibit tissue-specific estrogenic agonist/antagonist activity through their ability to bind to the estrogen receptor alpha (ER) protein and interact with coregulatory proteins, thereby modulating transcription of estrogen target genes. Since its first approval by the United States Food and Drug Administration (FDA) in 1977, tamoxifen has been found to (a) lower the risk of recurrence and death for women with early-stage hormone receptor-positive breast cancer, irrespective of menopausal and node status or use of adjuvant chemotherapy; (b) reduce the risk of invasive breast cancer following breast conservation in women with ductal carcinoma in situ (DCIS); and (c) reduce the risk of breast cancer in high-risk women. Toremifene is the only other SERM approved by the FDA for breast cancer treatment. However, it offers no clear clinical advantage over tamoxifen in the adjuvant or metastatic settings. Several other SERMs are in various phases of clinical development. In addition, strategies to combine SERMs with other endocrine therapy like ovarian suppression or aromatase inhibitors are active areas of investigations. At present, SERMs are recognized as the first targeted and relatively nontoxic medical therapy for women with high-risk or steroid hormone receptor-positive breast cancer.

First do no harm: extending the debate on the provision of preventive tamoxifen.

The Breast Cancer Prevention Trial (BCPT-P-1) demonstrated that tamoxifen could reduce the risk of invasive breast cancer in high-risk women by 49%, but that it could also increase the risk of endometrial cancer, vascular events and cataracts. This paper provides an estimate of the net health impacts of tamoxifen administration on high-risk Canadian women with no prior history of breast cancer. The results of the BCPT-P-1 were incorporated into the breast cancer and other modules of Statistics Canada’s microsimulation POpulation HEalth Model (POHEM). While the main intervention scenario conformed as closely as possible to the eligibility criteria for tamoxifen in the BCPT-P-1 protocol, 3 additional scenarios were simulated. Predicted absolute risks of breast cancer at 5 years of 1.66%, 3.32% and 4.15% were calculated for women 35 to 70 years of age. When the BCPT-P-1 results were incorporated into the simulation model, the analysis suggests no increase in life expectancy in this risk group. Tamoxifen appeared to be beneficial for women with a 5-year predicted risk of 3.32% or greater. The results of these simulations are particularly sensitive to the reduction in mortality observed in the BCPT-P-1, as well as being sensitive to other characteristics of the simulation model. Overall, the analysis raises questions about the use of tamoxifen in otherwise healthy women at high risk of breast cancer. © 2001 Cancer Research Campaign