American Society of Clinical Oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for women with hormone receptor-positive breast cancer: status report 2002.

OBJECTIVE: To conduct an evidence-based technology assessment to determine whether the routine use of anastrozole or any of the aromatase inhibitors in the adjuvant breast cancer setting is appropriate for broad-based conventional use in clinical practice. POTENTIAL INTERVENTIONS: Anastrozole, letrozole, and exemestane. OUTCOMES: Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefit. EVIDENCE: A comprehensive, formal literature review was conducted for relevant topics and is detailed in the text. Testimony was collected from invited experts and interested parties. The American Society of Clinical Oncology (ASCO)-prescribed technology assessment procedure was followed. BENEFITS/HARMS: The ASCO panel recognizes that a woman and her physician's decision regarding adjuvant hormonal therapy is complex and will depend on the importance and weight attributed to information regarding both cancer and non-cancer-related risks and benefits. CONCLUSION: The panel was influenced by the compelling, extensive, and long-term data available on tamoxifen. Overall, the panel considers the results of the Arimidex (anastrozole) or Tamoxifen Alone or in Combination (ATAC) trial and the extensive supporting data to be very promising but insufficient to change the standard practice at this time (May 2002). A 5-year course of adjuvant tamoxifen remains the standard therapy for women with hormone receptor-positive breast cancer. The panel recommends that physicians discuss the available information with patients, and, in making a decision, acknowledge that treatment approaches can change over time. Individual health care providers and their patients will need to come to their own conclusions, with careful consideration of all of the available data. (Specific questions addressed by the panel are summarized in Appendix 3.) VALIDATION: The conclusions of the panel were endorsed by the ASCO Health Services Research Committee and the ASCO Board of Directors.     

A practical overview of aromatase inhibitors in postmenopausal women with hormone receptor-positive breast cancer

Tamoxifen has been the standard adjuvant therapy for patients with breast cancer for the last several decades. Several recently completed adjuvant trials using aromatase inhibitors have shown the superiority of these agents over Tamoxifen or placebo, when used in postmenopausal women. The results from these trials present a challenging situation for practicing oncologists with regards to the choice, duration, sequence of therapy, follow up and side effects of aromatase inhibitors. We have discussed various management issues from a practical angle for oncologists to effectively use these agents, with an evidence-based approach.     

The role of aromatase inhibitors as adjuvant therapy for early breast cancer in postmenopausal women

For endocrine therapy of hormone-sensitive advanced breast cancer in postmenopausal women, the third-generation aromatase inhibitors, letrozole, anastrozole, and exemestane, are effective both as alternatives to tamoxifen in first-line treatment and following first-line tamoxifen failure. These three agents are currently being evaluated as adjuvant therapy of early breast cancer, again relative to the standard, tamoxifen. Three treatment strategies are under investigation: replacement of tamoxifen as adjuvant therapy for 5 years (early adjuvant therapy); sequencing of tamoxifen before or after an aromatase inhibitor during the first 5 years (early sequential adjuvant therapy); or following 5 years of tamoxifen (extended adjuvant therapy). Results of the first early adjuvant trial (Arimidex, Tamoxifen Alone or in Combination [ATAC]) demonstrated that anastrozole was significantly more effective than tamoxifen in reducing the risk of disease recurrence. Two trials sequencing 2-3 years of an aromatase inhibitor after 2-3 years of tamoxifen have also reported results. A large trial (International Collaborative Cancer Group [ICCG] trial 96) found switching to exemestane to be significantly superior to continuing on tamoxifen in disease-free survival, and in a small study (Italian Tamoxifen Arimidex [ITA] trial), similarly sequencing anastrozole after tamoxifen significantly reduced the hazard of recurrence compared with remaining on tamoxifen. Extended adjuvant therapy with 5 years of letrozole versus placebo following 5 years of tamoxifen was evaluated in the MA.17 trial. Compared with placebo, letrozole resulted in a significant improvement in disease-free survival that was irrespective of whether patients had lymph node-positive or -negative tumours. Results of these four trials emphasise the important role of aromatase inhibitors in the adjuvant setting, yet the optimal approach still needs to be defined. A number of trials further evaluating the three adjuvant treatment strategies are ongoing.     

第三代芳香化酶抑制剂在乳腺癌术后辅助治疗中的应用进展

近年来,第三代芳香化酶抑制剂应用于绝经后乳腺癌的辅助治疗,取得了令人鼓舞的结果,从而对他莫昔芬在乳腺癌辅助治疗中的地位提出了挑战。第三代芳香化酶抑制剂,特别是阿那曲唑有可能首先代替他莫昔芬成为绝经后妇女乳腺癌的新的标准辅助治疗药物。本文就近年来芳香化酶抑制剂的研究进展作一介绍和评述。     

Early switch with aromatase inhibitors as adjuvant hormonal therapy for postmenopausal breast cancer: pooled-analysis of 8794 patients

BACKGROUND: The magnitude of the survival benefit of aromatase inhibitors (AIs) after 2-3 years of tamoxifen as adjuvant hormonal therapy for early breast cancer is still unclear. We performed a literature-based meta-analysis, to look how much advantages adjuvant the "early switch" strategy add over standard tamoxifen for 5 years. METHODS: A pooled analysis of all phase-III trials was accomplished, and event-based relative risk ratios (RR) with 95% confidence interval (CI) were derived. Significant differences in primary outcome (EFS and RFS, event- and relapse-free survival), and secondary outcomes (OS, overall survival, deaths without progression, other cancers and toxicities), were explored. Magnitude outcome measures were absolute benefits and number of patients needed to treat. Heterogeneity test was applied as well. RESULTS: Five trials (8794 patients) were gathered. The risk of any event is reduced with AIs of 23%, with an absolute benefit of 3.8% (RR 0.67, 95% CI 0.59, 0.76). Again, RFS (RR 0.68, 95% CI 0.59, 0.79) or both LRFS and DFRS, were significantly improved with AIs. OS was significantly prolonged with AIs, with an absolute benefit of 1.2% (RR 0.76, 95% CI 0.62, 0.93), without significant heterogeneity. Bone fractures were significantly higher in patients receiving AIs (RR 1.50, 95% CI 1.12, 2.02), and endometrial cancer in patients who continued to receive tamoxifen (RR 0.32, 95% CI 0.13, 0.77), without significant heterogeneity. CONCLUSIONS: The early switch strategy improves survival over standard tamoxifen for 5 years, with a different toxicity profile. The lack of significant heterogeneity in the analysis underscores the homogenous effect across all trials.     

Do adjuvant aromatase inhibitors increase the cardiovascular risk in postmenopausal women with early breast cancer

BACKGROUND: Despite the advantages from using aromatase inhibitors (AIs) compared with tamoxifen for early breast cancer, an unexpectedly greater number of grade 3 and 4 cardiovascular events (CVAE) (as defined by National Cancer Institute of Canada-Common Toxicity Criteria [version 2.0] was demonstrated. METHODS: Phase 3 randomized clinical trials (RCTs) comparing AI with tamoxifen in early breast cancer were considered eligible for this review. The event-based risk ratios (RRs) with 95% confidence intervals (95% CIs) were derived, and a test of heterogeneity was applied. Finally, absolute differences (ADs) in event rates and the number of patients needed to harm 1 patient (NNH) were determined. RESULTS: Seven eligible RCTs (19,818 patients) reported CVAE results. When considering all RCTs, the AD of the primary endpoint (CVAE) between the 2 arms (0.52%), tamoxifen versus AI, was statistically significant (RR, 1.31; 95% CI, 1.07-1.60; P= .007). This translated into an NNH value of 189 patients; when only third-generation AIs were considered, the difference (0.57%) remained significant (RR, 1.34; 95% CI, 1.09-1.63; P= .0038). Thromboembolic events were significantly more frequent in the tamoxifen arm, regardless of the strategy adopted (RR, 0.53; 95% CI, 0.42-0.65; P< .0001), without significant heterogeneity (P= .21). An AD of 1.17% and an NNH value of 85 patients were observed. CONCLUSIONS: According to the results from this meta-analysis, the risk of grade 3 and 4 CVAEs in patients who were receiving AIs was higher compared with the risk in patients who were receiving tamoxifen, and the difference reached statistical significance. However, the AD was relatively low, and from 160 to 180 patients had to be treated to produce 1 event.     

Letrozole as adjuvant endocrine therapy in postmenopausal women with breast cancer

The third-generation aromatase inhibitor letrozole offers a promising approach to treating hormone-sensitive breast cancer for postmenopausal women, through potent and specific inhibition of estrogen synthesis. In neoadjuvant and first-line treatment, letrozole demonstrated superior efficacy compared with tamoxifen in randomized Phase III trials. Initial results of Breast InterGroup 1-98, a large ongoing randomized trial investigating primary adjuvant endocrine treatment with either letrozole or tamoxifen, have recently been presented. Patients treated with letrozole demonstrated a 19% improvement in disease-free survival and a significant reduced risk of distant recurrences, holding out the prospect of a survival advantage over tamoxifen treatment with further maturation of the trial. For patients who have already completed 5 years of tamoxifen, extended endocrine therapy with letrozole is a new therapeutic option based on the results of the MA-17 trial. The optimal use of aromatase inhibitors remains an open question, at least until results from randomized trials (BIG 1-98, TEAM) investigating the sequential use of an aromatase inhibitor and tamoxifen in comparison with continuous monotherapy become available.     

The use of aromatase inhibitors in adjuvant therapy for early breast cancer

Clinical evidence supporting the use of aromatase inhibitors (AIs) in adjuvant therapy for hormone-sensitive early breast cancer (EBC) has grown rapidly over the past few years and is reviewed in this article. The results of two studies-the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial and the Breast International Group (BIG) 1-98 trial-support the use of AIs as primary adjuvant therapy for EBC, with significantly prolonged disease-free survival, time to recurrence, and time to distant recurrence for both anastrozole and letrozole over tamoxifen. Furthermore, anastrozole has an established beneficial risk:benefit ratio compared with tamoxifen with mature data over the full 5-year recommended treatment period. For women who have already received 2-3 years of tamoxifen, switching studies with anastrozole [the Italian Tamoxifen Anastrozole (ITA) trial and the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 8/Arimidex-Nolvadex (ARNO 95) trial] and exemestane [the Intergroup Exemestane Study (IES)] have also shown that 5 years of primary adjuvant tamoxifen therapy is not optimal and that switching to an AI should be considered. Finally, for those women who have completed 5 years of tamoxifen, based on the results of the MA 17 trial, extended adjuvant treatment with letrozole should be considered. Although no sequencing data are available yet, current evidence suggests that an AI should be the adjuvant treatment of choice over tamoxifen, and anastrozole is the only AI with mature adjuvant data to date.     

Efficacy of adjuvant aromatase inhibitor in hormone receptor-positive postmenopausal breast cancer patients according to the body mass index

Background:

Increased adiposity may trigger signalling pathways that induce aromatase expression. As aromatase inhibitors exert their effects by blocking the aromatase enzyme, higher body mass index (BMI) can reduce the effect of aromatase inhibitors. Thus, we aimed to investigate retrospectively the effect of BMI on the efficacy of aromatase inhibitors in hormone receptor-positive postmenopausal patients with breast cancer.

Methods:

Newly diagnosed hormone receptor-positive breast cancer patients who were postmenopausal and non-metastatic were enrolled to the study. Patients with BMI ranging between 18.5 and 24.9 kg m⁻² were considered as normal weight patients (Arm A, n=102), and patients with a BMI ranging ⩾25 kg m⁻² were grouped as overweight and obese patients (Arm B, n=399).

Results:

In both normal weight and overweight patients, the baseline clinico-pathologic properties and the treatment history with radiotherapy and chemotherapy were similar, and with no statistically significant difference. In normal weight patients disease-free survival (DFS) rate was 93.7% and 77.6%, whereas in overweight and obese patients DFS rate was 96.8% and 85.5% in the first and third years, respectively, (P=0.08). Three year survival rate in Arm A patients was 98.3%, whereas in Arm B was 98.0% (P=0.57). When anastrozole was compared with letrozole in the subgroup analysis no difference with regard to DFS and overall survival was detected.

Conclusion:

These results, contradictory to the prior results, show that BMI has no worse effect on outcomes of aromatase inhibitors in postmenopausal hormone receptor-positive breast cancer patients. In the subgroup analysis, letrozole and anastrozole had similar survival outcomes.     

Use of aromatase inhibitors in postmenopausal women with advanced breast cancer

Surgeons have been involved in the management of metastatic breast cancer since the technique of ovarian ablation was introduced in 1896. However, as newer hormonal and chemotherapeutic regimens were developed, drug therapy gradually replaced surgery as the preferred treatment for metastatic breast cancer. Thus, management of metastatic breast cancer has largely shifted from surgeons to medical oncologists. Advances in hormonal pharmacology have placed hormonal therapy alongside surgery and radiation therapy as a standard treatment option for women with advanced breast cancer. The purpose of this article is to update surgeons on the current use of hormonal agents for treatment of advanced breast cancer in postmenopausal women, and to review the aromatase inhibitors, a new line of hormonal agents for the treatment of advanced breast cancer. J. Surg. Oncol. 1997;66:215–220. © 1997 Wiley-Liss, Inc.     

Meta-analysis of pre-operative aromatase inhibitor versus tamoxifen in postmenopausal woman with hormone receptor-positive breast cancer

Purpose  Clinical trials have reported conflicting results as to whether pre-operative aromatase inhibitors (AIs) improve outcome over pre-operative tamoxifen in postmenopausal women with hormone receptor-positive breast cancer. Methods  We performed a meta-analysis comparing primary and secondary end points of pre-operative AI and pre-operative tamoxifen. The event-based risk ratio (RR) with 95% confidence intervals (95% Cis) were derived, and a test of heterogeneity was applied. Results  Four studies (1,160 patients) met the inclusion criteria for the analysis. Meta-analysis showed that pre-operative AI was more effective than pre-operative tamoxifen. Pooled results of clinical efficacy were as follows: clinical objective response rate (RR, 1.29; 95% CI, 1.14–1.47; P < 0.001), ultrasound objective response rate (RR, 1.29; 95% CI, 1.10–1.51; P = 0.002), and breast conserving surgery (BCS) rate (RR, 1.36; 95% CI, 1.16–1.59; P < 0.001). Hot flashes, nausea, and fatigue were not different between the pre-operative AI and pre-operative tamoxifen groups. Although headache was more frequent in the pre-operative AI group (P = 0.011), it was a manageable toxicity and was not clinically relevant. Conclusion  Pre-operative AI has better BCS rate than tamoxifen and in terms of toxicities, is not inferior to tamoxifen; therefore, we could suggest pre-operative AI instead of tamoxifen for those postmenopausal patients with hormone receptor positive breast cancer, not eligible for chemotherapy.     

American Society of Clinical Oncology technology assessment on breast cancer risk reduction strategies: tamoxifen and raloxifene.

OBJECTIVE: To conduct an evidence-based technology assessment to determine whether tamoxifen and raloxifene as breast cancer risk-reduction strategies are appropriate for broad-based conventional use in clinical practice. POTENTIAL INTERVENTION: Tamoxifen and raloxifene. OUTCOME: Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefits. EVIDENCE: A comprehensive, formal literature review was conducted for tamoxifen and raloxifene on the following topics: breast cancer risk reduction; tamoxifen side effects and toxicity, including endometrial cancer risk; tamoxifen influences on nonmalignant diseases, including coronary heart disease and osteoporosis; and decision making by women at risk for breast cancer. Testimony was collected from invited experts and interested parties. VALUES: More weight was given to publications that described randomized trials. BENEFITS/HARMS/COSTS: The American Society of Clinical Oncology (ASCO) Working Group acknowledges that a woman's decision regarding breast cancer risk-reduction strategies will depend on the importance and weight attributed to the information provided regarding both cancer and non-cancer-related risks. CONCLUSIONS: For women with a defined 5-year projected risk of breast cancer of >/= 1.66%, tamoxifen (at 20 mg/d for up to 5 years) may be offered to reduce their risk. It is premature to recommend raloxifene use to lower the risk of developing breast cancer outside of a clinical trial setting. On the basis of available information, use of raloxifene should currently be reserved for its approved indication to prevent bone loss in postmenopausal women. Conclusions are based on single-agent use of the drugs. At the present time, the effect of using tamoxifen or raloxifene with other medications (such as hormone replacement therapy), or using tamoxifen and raloxifene in combination or sequentially, has not been studied adequately. The continuing use of placebo-controlled trials in other risk-reduction trials highlights the current unanswered issues concerning the use of such interventions, especially when the influence on net health benefit remains to be determined. Breast cancer risk reduction is a rapidly evolving area. This technology assessment represents an ongoing process with existing plans to monitor and review data and to update recommendations in a timely matter. (See VALIDATION: The conclusions of the Working Group were evaluated by the ASCO Health Services Research Committee and by the ASCO Board of Directors. SPONSOR: American Society of Clinical Oncology.     

Adjuvant therapy with aromatase inhibitors for postmenopausal women with early breast cancer: evidence and ongoing controversy

Results of five major randomized trials have increased our understanding of the role of aromatase inhibitors in the adjuvant setting. Two of these trials, the Anastrozole or Tamoxifen Alone or in Combination (ATAC) trial and the International Breast Cancer Study Group's BIG 1-98 trial compared an aromatase inhibitor versus tamoxifen as initial hormonal therapy. Three other trial were designed as cross-over studies; the Intergroup Exemestane Study (IES) and the Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 8/German ARNO 95 trial compared a crossover from tamoxifen to an aromatase inhibitor versus continued tamoxifen in women who had completed 2 to 3 years of tamoxifen. The MA-17 trial compared the use of letrozole with placebo for 5 years, following 5 years of tamoxifen. Based on the results of these studies, the use of an aromatase inhibitor for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer has largely replaced the previous standard of 5 years of tamoxifen. Still unanswered, however, are questions regarding optimal sequencing, selection of aromatase inhibitor, and duration of treatment. This review will provide an overview of the major studies with an emphasis on these important questions.     

Effectiveness and tolerability of fulvestrant in postmenopausal women with hormone receptor-positive breast cancer

Fulvestrant, an estrogen receptor antagonist that downregulates the estrogen receptor but has no known agonist effects, has been evaluated in 2 randomized trials involving postmenopausal women with hormone receptor-positive, progressive advanced-stage breast cancer after disease progression with antiestrogen therapy. These phase III studies, from which data were reported separately and in a planned combined analysis, showed that fulvestrant 250 mg per month intramuscularly was at least as effective as anastrozole 1 mg per day orally with respect to the primary endpoint of time to progression as well as secondary efficacy endpoints, which included objective response, clinical benefit, and survival. Both trials showed that patients treated with fulvestrant had a significantly longer duration of response, and a retrospective analysis found that pretreatment with fulvestrant did not preclude response to third-line hormonal therapy. More recently, fulvestrant was shown to be active as first-line hormonal therapy for advanced-stage breast cancer, with overall efficacy similar to that of tamoxifen in patients with hormone receptor-positive disease. Fulvestrant has been well tolerated in comparative trials published to date, translating into low study withdrawal rates and maintenance of quality of life. The incidence of adverse events was similar between the treatment arms in both trials of fulvestrant versus anastrozole, but it was notably lower for fulvestrant relative to tamoxifen in the first-line setting. In light of the results of comparative phase III trials, fulvestrant is effective and well tolerated in the treatment of postmenopausal women with hormone receptor-positive advanced-stage breast cancer.     

Aromatase inhibitors as adjuvant therapy for postmenopausal patients with early stage breast cancer

Endocrine therapy of hormone receptor-positive breast tumors is widely used as palliative therapy for metastatic breast cancer and as adjuvant therapy for early stage breast cancer. Tamoxifen has been the definitive standard of hormonal therapies for the last 30 years because of its documented efficacy and reasonable safety profile. Based on encouraging results from trials utilizing the selective, third generation aromatase inhibitors (AIs) in metastatic breast cancer, a number of trials were designed to examine these agents as adjuvant therapies. Trials directly comparing AIs with tamoxifen have, to date, demonstrated superior disease-free-survival with AIs. Likewise, trials examining the use of AIs after tamoxifen have demonstrated better outcomes compared with tamoxifen alone. Additionally, letrozole has been demonstrated to result in superior disease-free-survival after 5 years of adjuvant tamoxifen, compared with no further therapy. In general, the AIs are tolerated at least as well as tamoxifen but decrease bone mineral density and increase osteoporosis due to their lack of estrogenic effects on bone. Based on the fact that AIs appear more effective at preventing contralateral breast cancers than tamoxifen, they are being examined as breast cancer preventives. Despite available data using the AIs as adjuvant therapies, many questions remain unanswered, and further trials will be needed to address these important issues.     

American Society of Clinical Oncology technology assessment of pharmacologic interventions for breast cancer risk reduction including tamoxifen, raloxifene, and aromatase inhibition.

OBJECTIVE: To update an evidence-based technology assessment of chemoprevention strategies for breast cancer risk reduction. POTENTIAL INTERVENTIONS: Tamoxifen, raloxifene, aromatase inhibition, and fenretinide. OUTCOMES: Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefit. EVIDENCE: A comprehensive, formal literature review was conducted for relevant topics. Testimony was collected from invited experts and interested parties. The American Society of Clinical Oncology (ASCO) prescribed technology assessment procedure was followed. VALUES: More weight was given to published randomized trials. BENEFITS/HARMS: A woman's decision regarding breast cancer risk reduction strategies is complex and will depend on the importance and weight attributed to information regarding both cancer- and noncancer-related risks and benefits. CONCLUSIONS: For women with a defined 5-year projected breast cancer risk of > or= 1.66%, tamoxifen (at 20 mg/d for 5 years) may be offered to reduce their risk. Risk/benefit models suggest that greatest clinical benefit with least side effects is derived from use of tamoxifen in younger (premenopausal) women (who are less likely to have thromboembolic sequelae and uterine cancer), women without a uterus, and women at higher breast cancer risk. Data do not as yet suggest that tamoxifen provides an overall health benefit or increases survival. In all circumstances, tamoxifen use should be discussed as part of an informed decision-making process with careful consideration of individually calculated risks and benefits. Use of tamoxifen combined with hormone replacement therapy or use of raloxifene, any aromatase inhibitor or inactivator, or fenretinide to lower the risk of developing breast cancer is not recommended outside of a clinical trial setting. This technology assessment represents an ongoing process and recommendations will be updated in a timely matter. VALIDATION: The conclusions were endorsed by the ASCO Health Services Research Committee and the ASCO Board of Directors.