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 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anastrozole, a nonsteroidal selective aromatase inhibitor, has recently been approved in the US and several other countries for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. In the Arimidex, Tamoxifen alone or in Combination (ATAC) trial, anastrazole 1mg was significantly more effective than tamoxifen 20mg or combined treatment (17 and 19% relative risk reduction) for disease-free survival in postmenopausal women with early breast cancer. black triangle Anastrazole was also significantly more effective than tamoxifen for time to tumour recurrence and the odds of a primary contralateral tumour as a first event. During the first 2 years of treatment with anastrozole, tamoxifen or the combination, patient quality of life was similar in all treatment groups. Compared with tamoxifen, anastrozole was associated with a significantly lower incidence of vaginal bleeding, vaginal discharge, hot flushes, endometrial cancer, ischaemic cerebrovascular events, venous thromboembolic events and deep vein thrombosis including pulmonary embolism; tamoxifen was associated with a lower incidence of musculoskeletal disorders and fracture.
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PMID:Anastrozole: in early breast cancer. 1242 Nov 8

Tamoxifen has been the gold standard adjuvant therapeutic agent for postmenopausal women with hormone-sensitive breast cancer for > 25 years. Although it continues to play an important role in treating premenopausal women, tamoxifen's association with some serious safety and tolerability issues, including increased incidence of endometrial cancer and thromboembolic events, may be cause to limit its use in postmenopausal women. Anastrozole was the first drug to show improved efficacy and safety compared with standard therapies for first- and second-line therapy of hormone-sensitive advanced breast cancer in postmenopausal women. This article provides a review of the results of the first major analysis of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) early-stage breast cancer trial, initiated in 1996, and discusses the implications for the use of anastrozole in the adjuvant setting. This randomized, double-blind, multicenter trial compared tamoxifen (20 mg once daily) with anastrozole (1 mg) alone and in combination with tamoxifen, as adjuvant endocrine treatment for postmenopausal patients with operable, invasive, early-stage breast cancer. The results of the ATAC trial show anastrozole to be more effective and better tolerated than tamoxifen in this group of patients, and an updated follow-up suggests the therapeutic index for anastrozole will continue to remain superior to that of tamoxifen. Anastrozole is now emerging as a new standard for the adjuvant treatment of postmenopausal women with hormone-sensitive early-stage breast cancer. New adjuvant trials are currently using anastrozole in the control arm.
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PMID:Anastrozole as adjuvant therapy for early-stage breast cancer: implications of the ATAC trial. 1275 78

Published literature indicates that the selective estrogen-receptor modulators (SERMs) tamoxifen and raloxifene (Evista) have favorable effects on bone density, lipid profiles, and the incidence of second breast cancers, and unfavorable effects on the incidence of venous thrombosis and hot flushes. Tamoxifen increases the risk of endometrial cancer, but raloxifene does not. The effects of SERMs on sexual function and cognition are unclear. Because the selective antiaromatase agents are relatively new, the long-term effects of these agents on normal tissues are less well established. It appears that the nonsteroidal agents (anastrozole [Arimidex], letrozole [Femara]) and steroidal (exemestane [Aromasin]) antiaromatase agents may have different effects on normal tissues. Preliminary data demonstrate that anastrozole increases the risk of arthralgias and produces a decrease in bone density. In contrast, exemestane appears to favorably affect bone density and lipid profile, similar to tamoxifen and raloxifene. The incidence of contralateral breast cancer is decreased in women on adjuvant anastrozole, but data for the other antiaromatase agents are not yet available. Hot flushes have been reported with the use of selective aromatase inhibitors, but their incidence seems to be comparable to what is reported with SERMs. Antiaromatase agents do not appear to cause venous thrombosis. More information about the effects of the antiaromatase agents on normal tissue will become available as data from ongoing adjuvant and chemoprevention trials are reported. Clinically, we should be conscious of the differences between antiaromatase agents and SERMs and their impact on women's health.
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PMID:Long-term toxicities of selective estrogen-receptor modulators and antiaromatase agents. 1280 Jul 93

Tamoxifen is currently the adjuvant treatment of choice for postmenopausal women with hormone-sensitive breast cancer. However, in the treatment of postmenopausal women with advanced disease, the third-generation aromatase inhibitor anastrozole ('Arimidex') has been shown to be at least as effective as tamoxifen, and to be more effective than tamoxifen in patients with estrogen receptor-positive disease. Furthermore, anastrozole is well tolerated and is associated with fewer adverse reactions (such as thromboembolic events, vaginal bleeding, and endometrial cancer) compared with tamoxifen. A change in clinical practice has now emerged for the first-line treatment of postmenopausal advanced disease in patients, with tamoxifen becoming the second- or third-line choice for many clinicians. These data have raised questions about the optimal adjuvant treatment for postmenopausal women with early breast cancer. The 'Arimidex', Tamoxifen, Alone or in Combination (ATAC) trial has compared the efficacy and safety of tamoxifen and anastrozole in the adjuvant treatment of postmenopausal women with early breast cancer. At 3 years' follow-up in the overall population, anastrozole demonstrated a significant benefit compared with tamoxifen for disease-free survival (DFS) (89.4% vs. 87.4%; p = 0.013), time to recurrence (hazard ratio = 0.79; p = 0.008), and contralateral breast cancers (odds ratio = 0.42; 95% confidence interval: 0.22-0.79; p = 0.007). Anastrozole produced improvements in quality of life similar to tamoxifen and was better tolerated for a number of predefined adverse events. Of course, a large body of evidence is available regarding the safety profile of tamoxifen and some feel that more data are needed from the ATAC trial to demonstrate that the early advantages of anastrozole over tamoxifen can be maintained in the longer term. However, a follow-up analysis at 47 months has confirmed that the tolerability profile and the absolute benefit of anastrozole were maintained over the extended follow-up period, demonstrating that the benefits of anastrozole are likely to be maintained over the long term. This review assesses these and other data from the ATAC trial and presents the arguments for and against whether 3 years' follow-up is sufficient to inform a change in clinical practice for the adjuvant treatment of postmenopausal women with early breast cancer.
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PMID:Three years' follow-up from the ATAC trial is sufficient to change clinical practice: a debate. 1453 30

ATAC, a randomized, double-blind trial, compared tamoxifen (20 mg) with anastrozole ('Arimidex') (1 mg) alone, and the combination of anastrozole plus tamoxifen (combination), as adjuvant endocrine treatment for postmenopausal patients with early breast cancer. Patients with operable invasive breast cancer following completion of primary therapy, who were candidates to receive adjuvant endocrine therapy, were eligible for this study. Primary endpoints were disease-free survival (DFS) and tolerability. Other endpoints included time to recurrence (TTR: censoring non-breast cancer deaths before recurrence) and the incidence of contralateral breast cancer. A total of 9366 patients were included in this study (N=3125, 3116 and 3125 for anastrozole, tamoxifen and the combination, respectively). Median duration of therapy was 30.7 months and median follow-up was 33.3 months. The total numbers of events were 317, 379 and 383 for anastrozole, tamoxifen and the combination, respectively. DFS was significantly improved in the overall population for anastrozole versus tamoxifen (hazard ratio (HR)=0.81, 95% confidence interval (CI) (0.71-0.96), P=0.013). Anastrozole showed improved TTR compared with tamoxifen (HR=0.79, CI (0.67-0.94), P=0.008), which improved even further in the ER+ and/or PR+ subgroup (HR=0.73, CI (0.59-0.90), P=0.003). The incidences of hot flushes, thromboembolic events, ischaemic cerebrovascular events, vaginal bleeding/discharge and endometrial cancer were significantly reduced with anastrozole compared with tamoxifen (P<0.03 for all). Musculoskeletal disorders and fractures were significantly reduced in patients receiving tamoxifen compared with those on anastrozole (P<0.03 for both). No increase in hip fractures was seen for anastrozole versus tamoxifen (11 versus 13, respectively). Combination treatment was equivalent to tamoxifen in terms of both efficacy and tolerability. Anastrozole showed superior efficacy to tamoxifen for DFS, TTR and contralateral breast cancer. Early findings show anastrozole to be an effective and well-tolerated endocrine option for the treatment of postmenopausal patients with early breast cancer. For the first time a choice now exists for adjuvant endocrine treatment for postmenopausal women with hormone responsive tumours. Longer follow-up will further define the benefit/risk of anastrozole adjuvant therapy.
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PMID:'Arimidex' (anastrozole) versus tamoxifen as adjuvant therapy in postmenopausal women with early breast cancer--efficacy overview. 1462 37

The goal of endocrine therapy in breast cancer is to block the action of estrogen on the tumor cells either by inhibiting estrogen from binding to the specific estrogen receptor or by inhibiting its synthesis. Tamoxifen, a selective estrogen receptor modulator, is the standard endocrine treatment for hormone receptor-positive breast cancer, both in the adjuvant and metastatic settings. Tamoxifen inhibits the binding of estrogen to the receptor, resulting in inhibition of hormone action. However, as tamoxifen is also weakly estrogenic, it may not be optimally effective and increases the risk of endometrial cancer and stroke. Furthermore, patients may be refractory or may become resistant to tamoxifen treatment. Since aromatase inhibitors (AI) block the synthesis of estrogen and have no intrinsic estrogenic activity, they have the potential to be more effective than tamoxifen. Their different mechanism of action and chemical structures may also circumvent tamoxifen resistance. Consequently, AIs are currently being evaluated as an alternative to tamoxifen treatment. A preclinical model has recently been developed to compare the efficacy of AIs and antiestrogens in different treatment schemes and to assist in the design of clinical trials. Current studies with the MCF-7Ca xenograft model are exploring the effects of combination and sequential therapy on tumor growth. The efficacy of AIs in the treatment of hormone receptor-positive breast cancer was first demonstrated in five multicenter second-line trials enrolling several hundreds of postmenopausal patients with metastatic breast cancer who had failed tamoxifen treatment. More recently, anastrozole demonstrated efficacy at least equivalent to that of tamoxifen in first-line randomized, phase III clinical trials in postmenopausal women with hormone receptor-positive or unknown metastatic breast cancer, whereas letrozole demonstrated superiority. The steroidal AI exemestane is currently under evaluation. Letrozole is the only AI to have been studied in a randomized, phase III trial in the neoadjuvant setting. In this trial, more patients underwent breast-conserving surgery with letrozole than with tamoxifen. Smaller phase II studies also suggest that both anastrozole and exemestane are active in the neoadjuvant setting. Because neoadjuvant trials permit temporal sampling of breast tissue, substudies in the phase III trial with letrozole have examined the impact of such biomarkers as estrogen receptor, progesterone receptor and epidermal growth factor receptor family members, HER-1 and HER-2, on patient response. AIs are currently under evaluation in the adjuvant setting, and preliminary results of the Arimidex, Tamoxifen Alone or in Combination (ATAC) trial have been reported. AIs have proven as safe as tamoxifen in trials in patients with metastatic breast cancer. Ongoing clinical trials in the adjuvant setting include companion studies of end-organ effects, particularly bone metabolism and lipid metabolism evaluations. Quality-of-life assessments are also parts of major clinical trials. A head-to-head quality-of-life assessment of anastrozole compared with letrozole demonstrated patient preference for letrozole. These assessments also clearly indicated the eagerness of patients to participate actively in treatment decisions
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PMID:Challenges in the endocrine management of breast cancer. 1465 38

This commentary article provides an overview of recent clinical research trials involving anastrozole and its evolving role in the management of breast cancer. Anti-aromatase agents inhibit the cytochrome P-450 component of the aromatase enzyme complex responsible for the final step of estrogen biosynthesis in peripheral tissues which are the main source of estrogen in postmenopausal women. Anastrozole is a third-generation non-steroidal aromatase inhibitor. It has been shown to be superior to megestrol acetate, in terms of survival and adverse effects, as a second-line therapy in postmenopausal women with estrogen receptor (ER)- and/or progesterone receptor (PgR)-positive advanced breast cancer. Phase III clinical trials have also demonstrated that anastrozole significantly prolongs the time to tumour progression compared with tamoxifen as a first-line therapy for ER- and/or PgR-positive advanced breast cancer in postmenopausal women. Furthermore, the preliminary results of the Arimidex, Tamoxifen, Alone and in Combination (ATAC) study have shown that adjuvant anastrozole is superior to tamoxifen in terms of disease-free survival (DFS), non-musculoskeletal adverse effects and prevention of contralateral breast cancer in postmenopausal women with early, ER-positive breast cancer. Although longer follow-up is required to assess the long-term effects of anastrozole on bone mineral density, cognitive function and overall survival, the drug has been recently approved for adjuvant use in postmenopausal women with early, ER-positive breast cancer who are unable to tolerate tamoxifen or at an increased risk of developing thromboembolism or endometrial cancer. The potential role of anastrozole in the neoadjuvant setting, the management of DCIS, premenopausal breast cancer and breast cancer prevention is currently being investigated.
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PMID:Focus on anastrozole and breast cancer. 1468 37

Tamoxifen has become the standard of care in relation to hormonal therapy for women with hormone-sensitive tumors. However, recently completed and ongoing studies indicate that third-generation aromatase inhibitors may be more effective than tamoxifen for a wide range of patients with breast cancer. Drugs in this class currently are approved as first-line endocrine therapy for postmenopausal women with metastatic hormone-dependent breast cancer, and as second-line endocrine therapy after failure of antiestrogen therapy alone or multiple hormonal therapies. The interim results from the Arimidex, Tamoxifen Alone or in Combination Trial support the use of an aromatase inhibitor as an alternative to tamoxifen for adjuvant therapy in postmenopausal women with operable breast cancer that is hormone positive. In this trial, anastrozole had a favorable side effect profile, with fewer cases of endometrial cancer and fewer thromboembolic events than tamoxifen. Other recent studies have indicated that an aromatase inhibitor may be superior to tamoxifen as preoperative treatment for women with hormone-sensitive, primary breast cancer. Numerous clinical trials currently are comparing the efficacy of aromatase inhibitors with that of tamoxifen used as adjuvant therapy for postmenopausal women who have early-stage breast cancer. The results of these trials will provide additional information about the best ways to use these powerful agents for patients with breast cancer.
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PMID:New developments in endocrine therapy: role of adjuvant therapy for early breast cancer. 1502 6

Until recently, tamoxifen was the only adjuvant endocrine therapy for postmenopausal women with hormone receptor-positive, early-stage breast cancer. However, the first efficacy update from the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial has introduced a choice of adjuvant therapy in this setting. After a median follow-up of 47 months, these data indicated that anastrozole continued to show superior efficacy compared with tamoxifen, including significantly greater disease-free survival, a longer median time to recurrence, and a reduced incidence of contralateral breast cancer. Anastrozole also exhibited a number of important tolerability benefits compared with tamoxifen, including reduced incidences of thromboembolic events, vaginal bleeding, and endometrial cancer. Additional ATAC subprotocols included the examination of bone mineral density and its associated sequelae, endometrial abnormalities, and quality of life. The results of these studies support the primary conclusions of the main efficacy and safety analyses: the efficacy benefits of anastrozole were not at the expense of quality of life, anastrozole was associated with reduced endometrial stimulation compared with tamoxifen, and only patients receiving tamoxifen had endometrial atypical hyperplasia. Anastrozole was associated with a modest loss of bone mineral density and an initial increase of fractures compared with tamoxifen. However, the fracture rate with anastrozole stabilizes after 2 years, and indirect comparison suggests that any increased fracture risk with anastrozole is modest. This review concludes that, based on the overall risk-benefit profile from the ATAC study, anastrozole is a rational alternative to tamoxifen for the adjuvant treatment of women with hormone-sensitive early-stage breast cancer.
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PMID:The ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial: an update. 1534 33

Adjuvant hormonal therapy in the treatment of women with early-stage, hormone receptor (HR)-positive breast cancer is now considered the standard of care. Adjuvant tamoxifen decreases the risk of breast cancer recurrence and death in women with early-stage breast cancer when taken for 5 years. The benefits of tamoxifen are counterbalanced by toxicities including an increased risk of endometrial cancer and thromboembolic events. The selective aromatase inhibitors (AIs)--including anastrozole, letrozole, and exemestane--are challenging the role of tamoxifen as the adjuvant hormonal therapy of choice in postmenopausal women. Results of the Arimidex and Tamoxifen Alone or in Combination trial favor the use of anastrozole over tamoxifen as initial adjuvant hormonal therapy, with improvement in disease-free survival (DFS) and a favorable toxicity profile. The results of 2 large adjuvant trials using AIs sequentially with tamoxifen in postmenopausal women with early-stage, HR-positive breast cancer have been reported. The MA-17 study randomized women to placebo or letrozole for 5 years after completion of 4.5-6 years of initial tamoxifen. The Intergroup Exemestane Study (IES) randomized women following 2-3 years of adjuvant tamoxifen to continue to receive tamoxifen or switch to exemestane for a total of 5 years of adjuvant hormonal therapy. The MA-17 and IES trials demonstrated superior DFS with the AI and corroborated the smaller GROCTA-4B and Italian Tamoxifen Arimidex trials, which studied sequential therapy with aminoglutethamide or anastrozole. There is now substantial medical evidence supporting the use of AIs in postmenopausal women with early-stage, HR-positive breast cancer.
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PMID:Adjuvant aromatase inhibitors following tamoxifen for early-stage breast cancer in postmenopausal women: what do we really know? 1534 35


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