Combined tamoxifen and luteinizing hormone-releasing hormone (LHRH) agonist versus LHRH agonist alone in premenopausal advanced breast cancer: a meta-analysis of four randomized trials

Endocrine therapy for breast cancer: an overview

Endocrine therapy for breast cancer has been established in the adjuvant treatment for primary disease and in the treatment of advanced disease. The ER remains the best predictor of response although other factors exist and need to be identified. Pharmacological manipulation has been replacing ablative procedures. Tamoxifen used to be the most popular agent of choice and promising new agents include the pure anti-oestrogens and the third generation selective aromatase inhibitors. Ongoing and future studies will optimise treatment in established areas and will exploit its potential roles in preoperative use and chemoprevention.

The model-based cost-effectiveness analysis of 1-year adjuvant trastuzumab treatment: based on 2-year follow-up HERA trial data

BACKGROUND

Several randomized controlled trials have confirmed the usefulness of trastuzumab as an adjuvant therapy for HER2-overexpressed breast cancer patients; however, the costs for 1-year treatment are high. Therefore, we performed an economic analysis regarding the efficient distribution of medical resources.

METHODS

To analyze the cost-effectiveness for a 1-year adjuvant trastuzumab treatment group compared with the observation group, we constructed a Markov model adopting a 3% per year discount rate for costs and outcomes. The time horizon was 50 years. The perspective was that of health-care payers, as only direct medical costs were calculated. The outcome was measured as life-year gained (LYG) from 2-year follow-up HERA trial data.

RESULTS

The ICER of the standard setting (5 years efficacy and 50-60 kg patient weight) was JPY 2,600,000 (<euro>17,000) per LYG. The calculation results of other weight class ICER were JPY 2,200,000 (<euro>15,000) and JPY 3,300,000 (<euro>22,000) per LYG for the patients, respectively, who weighed less than 50 kg, and 60-75 kg. In the sensitivity analysis, the period of trastuzumab efficacy was the most influential parameter for the result of cost-effectiveness. However, even if the trastuzumab efficacy were to continue for only 2 years, at least, which is a conservative setting judging from the joint analysis (NSABP B-31 and NCCTG N9831 trials), the ICER remains acceptable for any weight class.

CONCLUSION

These results suggest that the 1-year adjuvant trastuzumab treatment is cost-effective. Both clinical and economic benefits were superior for the 1-year adjuvant trastuzumab treatment group compared with the observation group.

Adjuvant endocrine treatment of early breast cancer

Endocrine therapy plays a pivotal role in the early treatment of estrogen receptor (ER)-positive breast cancer. Although evidence suggests that chemotherapy may work partly through ovarian ablation in young women who have ER-positive tumors, combined chemotherapy and endocrine therapy are generally advocated. In postmenopausal women, aromatase inhibition has become the new "gold standard" of treatment. More research is needed to define optimal regimens (aromatase inhibitor monotherapy versus tamoxifen sequential application), optimal duration of therapy and potential advantages of particular compounds. The optimal use of estrogen suppression (ovarian ablation with or without aromatase inhibition) and tamoxifen (administered sequentially or in concert with ovarian ablation) in premenopausal women has yet to be defined.

Hormonal therapy for advanced breast cancer

Hormonal therapy for advanced breast cancer has evolved significantly in the more than 100 years since the first publications documenting the effect of ovarian ablation on advanced breast cancer in premenopausal women. Since that time, not only have we developed the methods to measure estrogen and progesterone receptors in cancer cells, but more recently we have understood that expression of these receptors determines response to hormone therapy. The availability of more selective antiestrogen therapies has changed and significantly improved the treatment options for women who have advanced hormone-responsive breast cancer. Current research is focusing on reversing resistance to hormone therapy with the addition of targeted biologic agents to standard hormonal treatment.

Breast Cancer Adjuvant Endocrine Therapy

Adjuvant endocrine therapy with the selective estrogen receptor modulator, tamoxifen, has significantly improved mortality from early-stage breast cancer for both pre- and postmenopausal women with hormone receptor-positive breast cancer. Recent large clinical trials have demonstrated a clear and consistent benefit for the incorporation of aromatase inhibitor (AI) therapy within adjuvant endocrine regimens for postmenopausal women. The AIs, which are associated with myalgias, arthralgias, and a reduction in bone mineral density, are generally well tolerated and have lower risks of endometrial carcinoma and thromboembolic events than tamoxifen. Data are awaited from ongoing trials to better define the optimal sequencing strategy, duration, and AI agent. Attempts to further optimize adjuvant endocrine therapy by identifying predictive biomarkers of response, as well as by developing strategies to overcome endocrine resistance are underway. In premenopausal women AI monotherapy is currently contraindicated and tamoxifen remains the standard of care. The role of ovarian function suppression in addition to tamoxifen or combined with AI therapy is being explored. The hope is that continued advances in endocrine therapy will translate into improved survival among both pre- and postmenopausal women with receptor-positive breast cancer.

Luteinizing hormone-releasing hormone agonists in premenopausal hormone receptor-positive breast cancer

Ovarian function suppression for the treatment of premenopausal breast cancer was first used in the late 19th century. Traditionally, ovarian function suppression had been accomplished irreversibly via irradiation or surgery, but analogues of the luteinizing hormone-releasing hormone (LH-RH) have emerged as reliable and reversible agents for this purpose, especially the LH-RH agonists. Luteinizing hormone-releasing hormone antagonists are in earlier stages of development in breast cancer and are not currently in clinical use. Luteinizing hormonereleasing hormone agonists act by pituitary desensitization and receptor downregulation, thereby suppressing gonadotrophin release. Limited information is available comparing the efficacies of the depot preparations of various agonists, but pharmacodynamic studies have shown comparable suppressive capabilities on estradiol and luteinizing hormone. At present, only monthly goserelin is Food and Drug Administration-approved for the treatment of estrogen receptor-positive, premenopausal metastatic breast cancer in the United States. Luteinizing hormone-releasing hormone agonists have proven to be as effective as surgical oophorectomy in premenopausal advanced breast cancer. They offer similar outcomes compared with tamoxifen, but the endocrine combination appears to be more effective than LH-RH agonists alone. In the adjuvant setting, LH-RH agonists versus no therapy reduce the annual odds of recurrence and death in women aged>50 years with estrogen receptor-positive tumors. Luteinizing hormone-releasing hormone agonists alone or in combination with tamoxifen have shown disease-free survival rates similar to chemotherapy with CMF (cyclophosphamide/methotrexate/5-fluorouracil). Outcomes of chemotherapy with or without LH-RH agonists are comparable, though a few trials favor the combination in young premenopausal women (aged<40 years). Adjuvant LH-RH agonists with or without tamoxifen might be as efficacious as tamoxifen alone, and the additional benefit from chemotherapy is unclear. Adequately powered studies are now studying the relative merits of combining adjuvant tamoxifen or aromatase inhibitors with ovarian function suppression, the additional benefits of adding ovarian function suppression to chemotherapy, and the need for adjuvant chemotherapy for women treated with combined ovarian function suppression and anti-estrogen therapy.

Controversies in preservation of ovary function and fertility in patients with breast cancer

Improved treatment of breast cancer in premenopausal patients increased survival rates, but the therapy may influence fertility and ovarian function. Currently there is a big public and individual interest of breast cancer affected women in preservation of ovarian function and fertility. Chemotherapy induced amenorrhea (CIA) has many objective (osteoporosis, cardiovascular, urogenital atrophy, cognitive etc.) and subjective (hot flushes, sleep disturbances, change of mood etc.) consequences. In patients with breast cancer who wish to avoid a CIA and to preserve their fertility ovarian protection by GnRH agonists, cryopreservation of operative sampled ovarian tissue or obtained fertilized or non-fertilized eggs after stimulation and puncture or embryos after in vitro fertilization are technically possible. However there are no evidence-based recommendations for preservation of fertility or ovarian function in breast cancer patients. Except the cryopreservation of embryos all other procedures are experimental. It is also undefined who is going to carry the costs. Moreover, there are recent data that the reappearance of ovarian hormones may stimulate occult tumor cells in hormone sensitive breast cancer. Therefore it seems necessary to inform breast cancer patients about the possible negative effects of preservation of ovarian function.

Bisphosphonates for Breast Cancer: Questions Answered, Questions Remaining

Bone is an important organ that is essential to adult hematopoiesis, electrolyte balance, and locomotion. Individuals who have metastatic breast cancer involving the bone are at increased risk for skeletal complications and those who have a history of early-stage breast cancer may be at increased risk for fragility fractures. Maintaining bone integrity is critical to control the morbidity and mortality associated with fractures and other skeletal complications. The bisphosphonates have been shown to be efficacious in decreasing the risk for skeletal complications in cancer and in osteoporosis. The article reviews the use of bisphosphonates in patients who have breast cancer.

Recent perspectives of endocrine therapy for breast cancer

The choice of endocrine therapy for breast cancer depends on the menopausal status and stage of disease. Endocrine therapy remains the first choice and most important component in the treatment of hormone sensitive non-life threatening advanced breast cancer. In premenopausal women with metastatic disease, the combination of a luteinizing hormone-releasing hormone (LH-RH) agonist plus tamoxifen is reasonable as first-line endocrine therapy. In postmenopausal patients with recurrent disease progressing after or during adjuvant tamoxifen, third-generation aromatase inhibitors (AIs) are the preferred first-line endocrine treatment. Many premenopausal and postmenopausal women with hormone responsive breast cancer benefit from sequential use of endocrine therapies at the time of disease progression. Recent clinical trials designs have been implemented, employing AIs as monotherapy in postmenopausal breast cancer patients, as first-line adjuvant therapy, and in sequence either 2-3 or 5 years, with initial tamoxifen. Emerging results from these trials indicate an advantage to patients for any of these strategies, and most international guidelines now suggest the use of an AI in the adjuvant setting in postmenopausal women. The use of endocrine treatment for metastatic and early breast cancer will be reviewed here.

Drug Insight: clinical use of agonists and antagonists of luteinizing-hormone-releasing hormone

This article reviews the clinical uses of agonists and antagonists of luteinizing-hormone-releasing hormone (LHRH), also known as gonadotropin-releasing hormone. In particular, the state of the art treatment of breast, ovarian and prostate cancer, reproductive disorders, uterine leiomyoma, endometriosis and benign prostatic hypertrophy is reported. Clinical applications of LHRH agonists are based on gradual downregulation of pituitary receptors for LHRH, which leads to inhibition of the secretion of gonadotropins and sex steroids. LHRH antagonists immediately block pituitary LHRH receptors and, therefore, achieve rapid therapeutic effects. LHRH agonists and antagonists can be used to treat uterine leiomyoma and endometriosis; furthermore, both types of LHRH analogs are used to block the secretion of endogenous gonadotropins in ovarian-stimulation programs for assisted reproduction. The preferred primary treatment of patients with advanced, androgen-dependent prostate cancer is based on the periodic administration of depot preparations of LHRH agonists; these agonists can be likewise used to treat estrogen-sensitive breast cancer in premenopausal women. LHRH antagonists have been successfully used to treat prostate cancer and benign prostatic hypertrophy. Since receptors for LHRH are present on a variety of human tumors, (notably breast, prostate, ovarian, endometrial and renal cancers), cytotoxic therapy that targets these tumors with hybrid molecules of LHRH might be possible in the near future. Analogs of LHRH are now a well-established means of treating sex-steroid-dependent, benign and malignant disorders.

Treatment of Premenopausal Women with Early Breast Cancer

Breast cancer occurring in women before the age of menopause continues to be a major medical and psychological challenge. Endocrine therapy has emerged as the mainstay of adjuvant treatment for women with estrogen receptor-positive tumours. Although the suppression of ovarian function (by oophorectomy, irradiation of the ovaries or gonadotropin releasing factor analogues) is effective as adjuvant therapy if used alone, its value has not been proven after chemotherapy. This is presumably because of the frequent occurrence of chemotherapy-induced amenorrhoea. Tamoxifen reduces the risk of recurrence by approximately 40%, irrespective of age and the ovarian production of estrogens. The worth of ovarian function suppression in combination with tamoxifen is unproven and is being investigated in an intergroup randomised clinical trial (SOFT [Suppression of Ovarian Function Trial]). Aromatase inhibitors are more effective than tamoxifen in postmenopausal women but are only being investigated in younger patients. The use of chemotherapies is identical in younger and older patients; however, at present the efficacy of chemotherapy in addition to ovarian function suppression plus tamoxifen is unknown in premenopausal patients with endocrine responsive disease. 'Targeted' therapies such as monoclonal antibodies to human epidermal growth factor receptor (HER)-2, HER1 and vascular endothelial growth factor, 'small molecule' inhibitors of tyrosine kinases and breast cancer vaccines are rapidly emerging. Their use depends on the function of the targeted pathways and is presently limited to clinical trials. Premenopausal patients are best treated in the framework of a clinical trial.

Antihormones in Prevention and Treatment of Breast Cancer

Breast cancer has the highest incidence of all types of cancer in women. Age and family history are the strongest risk factors, but sex hormones also play an important role, as demonstrated by epidemiological studies reporting a consistent association by reproductive personal history and breast cancer risk. The acceptability of preventive strategies by healthy women is closely related to their lifetime risk of developing breast cancer. Although surgical prevention may be considered in carriers of BRCA1/2 mutation, this option cannot be advocated for the majority of women whose risk is only moderately increased. In these women, chemoprevention with tamoxifen may reduce the incidence of estrogen receptor (ER)-positive breast carcinoma by 30-50%. Other drugs such as raloxifen and aromatase inhibitors (AIs) are currently being tested in this setting. Tamoxifen has been the most successful hormonal treatment over the last 30 years and, until recently, the most active drug in endocrine-sensitive breast cancer. In premenopausal breast cancer, tamoxifen still represents the therapy of choice, alone or in association with ovarian suppression. Conversely, in postmenopausal women it has been overtaken by third-generation AIs as first-choice drugs both in the adjuvant and metastatic settings. Many other issues, such as the optimal sequence between tamoxifen and AIs, the duration of AIs treatment, and the association of ovarian suppression and AIs in premenopausal patients still await the completion of randomized clinical trials. Furthermore, it is likely that treatment tailoring will be increased by the definition of patient subgroups that could derive larger benefits from AIs (progesterone receptor-negative, HER-2-overexpressing) or other new drugs.

Continuous versus intermittent tamoxifen versus intermittent/alternated tamoxifen and medroxyprogesterone acetate as first line endocrine treatment in advanced breast cancer: an EORTC phase III study (10863)

BACKGROUND

Continuous ligand depletion of endocrine responsive tumours may enhance resistance to therapy. Intermittent treatment with tamoxifen (T) was considered to mimic (incomplete) ligand depletion and reintroduction. Furthermore it was postulated that alternating tamoxifen with a non-cross resistant endocrine modality could (further) postpone hormone resistance.

PATIENTS AND METHODS

Postmenopausal patients with advanced breast cancer who did not progress after 4 months of first line T therapy were randomised to continue T (40 mg daily) or to 2 monthly intermittent T or intermittent/alternated T and medroxyprogesterone acetate (MPA, 300 mg daily). At progression during break or during MPA, T should be reintroduced. Endpoints of the study were progression free survival (PFS), time to resistance to tamoxifen and overall survival (OS).

RESULTS

Of 593 registered patients, 276 were randomised. After 8 years follow-up the median PFS for continuous T, intermittent T and intermittent/alternated T and MPA was 11.0 (8.1-15.2), 8.0 (6.2-12.4) and 10.8 (7.1-16.7) months, respectively (NS). Resistance to tamoxifen was established only in 84%, 70% and 55% of patients in the three treatment arms, respectively. The median times from randomisation to resistance to tamoxifen were 12.5 (9.1-21.1), 13.2 (8.8-19.8) and 24.0 (16.9-60.9) months, respectively (p<0.001), without translation in differences in survival times.

CONCLUSION

Intermittent T or intermittent/alternated T and MPA had no impact on PFS or OS as compared with classical continuous T in patients with advanced breast cancer. Intermittent/alternated T and MPA resulted in prolonged time to resistance to T, but this might partly be due to bias by omittance of the proof of tamoxifen resistance in a high proportion of the patients in this treatment arm.

Combined ovarian ablation and aromatase inhibition as first-line therapy for hormone receptor-positive metastatic breast cancer in premenopausal women: report of three cases

Aromatase inhibitors have become well established for the treatment of postmenopausal women with hormone receptor-positive metastatic breast cancer and for adjuvant hormonal therapy for primary breast cancer. Benefit of aromatase inhibition has not yet been extended to premenopausal women. Ovarian ablation by oophorectomy, ovarian radiation or hormonal suppression is the initial recommended treatment for hormone receptor-positive metastatic breast cancer in premenopausal women. The addition of tamoxifen improves the benefit of ovarian ablation/ovarian suppression. Addition of aromatase inhibitors to luteinizing hormone-releasing hormone analogs has been reported to significantly decrease circulating estrogens and produce tumor responses in only a very small number of patients over the last 15 years. We treated three premenopausal patients with hormone receptor-positive metastatic breast cancer with combined oophorectomy or ovarian irradiation and anastrozole. One patient remained free of progression for 4 years, while the other two remained free of progression for more than 5 and 3 years, respectively. We also note that monthly zoledronic acid for 4 years produced sclerosis of vertebral body metastasis. We conclude that combined ovarian ablation and aromatase inhibition is a feasible treatment modality that deserves more attention and further investigation for hormone receptor-positive metastatic breast cancer in premenopausal women.

Complete hormonal blockade versus epirubicin-based chemotherapy in premenopausal, one to three node-positive, and hormone-receptor positive, early breast cancer patients: 7-year follow-up results of French Adjuvant Study Group 06 randomised trial

BACKGROUND

The purpose of this study was to determine optimal adjuvant therapy between complete hormonal blockade in premenopausal patients with hormone receptor positive breast cancer and one to three positive nodes.

PATIENTS AND METHODS

We randomised 333 patients to receive either LHRH agonist (triptorelin 3.75 mg i.m., monthly) plus tamoxifen 30 mg/day for 3 years (TAM-LHRHa, n=164), or fluorouracil 500 mg/m2, epirubicin 50 mg/m2 and cyclophosphamide 500 mg/m2 every 21 days for six cycles, without any hormonal treatment (FEC50, n=169).

RESULTS

The 7-year disease-free survival (DFS) was 76% with TAM-LHRHa, and 72% with FEC50 (P=0.13). The 7-year overall survival (OS) was 91% and 88%, respectively (P=0.20). The multivariate analysis confirmed that both treatments were not different for DFS and OS (P=0.83 and P=0.41, respectively). Amenorrhoea occurred in 64% of patients treated with FEC50; it was temporary in 58% of cases after hormonotherapy and in 31% after chemotherapy.

CONCLUSION

In intermediate-risk breast cancer, complete hormonal blockade and chemotherapy provided similar outcomes. Hormonal treatment is an alternative to chemotherapy in hormone-sensitive patients, considering the preference of patients in terms of quality of life.

Second consensus on medical treatment of metastatic breast cancer

The present consensus manuscript defines evidence-based recommendations for state-of-the-art treatment of metastatic breast cancer depending on disease-associated and biologic variables.

Selection of optimal adjuvant endocrine therapy for early-stage breast cancer

Oophorectomy was found to cause regression of advanced breast cancer toward the end of the 19th century. Decades later, the discovery that estrogen plays a central role in this process eventually led to two important consequences: first, different modalities were developed to suppress or antagonize estrogen; and second, the ability to detect estrogen receptor in breast cancer tissue became a predictor of response to treatment--probably the best marker for response among all solid tumors. Tamoxifen, which works by competitively antagonizing hormonal receptors in breast cancer cells, has been for the past three decades the standard of care for adjuvant therapy for any woman with hormone receptor-positive early breast cancer, regardless of nodal status or menopausal setting. But as we strive to improve the utility of antagonizing or suppressing estrogen, new modalities are being developed. In the premenopausal setting, the advent of gonadotropin hormone-releasing hormone (also known as luteinizing hormone-releasing hormone) analogues has allowed for medical and reversible suppression of ovarian function. This method has already been proven as effective as chemotherapy in preventing recurrence, and ongoing trials are aiming to better define its role in the adjuvant setting. In the postmenopausal setting, aromatase inhibitors (AIs) have revolutionized the adjuvant treatment of hormone-responsive cancers of all stages. The current standard of care has come to include AIs, as an alternative, in sequence, of after 5 years of tamoxifen. Ongoing research continues to develop agents to overcome hormonal therapy resistance.

Quality of systematic reviews used in guidelines for oncology practice

BACKGROUND

Systematic reviews are an important tool for developing clinical recommendations. Those of high quality assure a good level of confidence on the strength of the recommendations.

METHODS

A QUOROM-based checklist was applied to the reviews cited in a sample of guidelines on breast and colon cancer prevention and therapy. The checklist provided a weight for each criterion and a total quality score. Each review was independently evaluated by two reviewers; disagreements were solved by consensus.

RESULTS

Eighty reviews (96%) were retrieved and evaluated; 36 focused on breast, and 44 on colorectal cancer. Twenty-three reviews (29%) did not match the definition of systematic review. In 17 (21%) the searching methods were unclear or described elsewhere. Forty (50%) were systematic. Not systematic, low and very low quality reviews accounted for 70% of the total. No review obtained the A+ class score; only 5 (6%) the A- and 7 (9%) the B+.

CONCLUSIONS

The results of this assessment provide a sober picture of the quality of the sources used to build guidelines. Oncologists should be aware that they could be relying on poor underlying documents. Writing groups should be aware of methodological problems, and should consult the existing manuals for the preparation of guidelines.

Trends in endocrine therapy and chemotherapy for early breast cancer: a focus on the premenopausal patient

PURPOSE

The majority of breast cancers are diagnosed at an early stage, and treatment is focused on cure and prolonging disease-free survival. Local therapy (surgery and/or radiation treatment) is standard, along with systemic adjuvant therapy that may effectively prevent or delay relapse and death in early-stage disease. In premenopausal women, adjuvant therapeutic approaches include combination cytotoxic chemotherapy and endocrine therapy. Cyclophosphamide, methotrexate and 5-fluorouracil (CMF) was the established chemotherapy regimen; however, newer regimens have more recently been introduced that may offer some benefit over CMF including anthracycline-containing regimens [e.g. cyclophosphamide, epirubicin and 5-fluorouracil (CEF)], and taxane-containing regimens. For women with oestrogen receptor (ER)-positive disease, a second option is endocrine therapy that aims to suppress mitogenic oestrogen signalling. Until recently, 5 years of tamoxifen was regarded as the standard adjuvant endocrine treatment in ER-positive disease. Ovarian ablation is also effective in premenopausal women, and can be achieved by surgery, radiotherapy, or via the use of a luteinising hormone-releasing hormone analogue such as goserelin. Combining tamoxifen and goserelin treatment provides more effective oestrogen blockade than either drug alone. However, as the third-generation aromatase inhibitors (AIs) have demonstrated improved efficacy over tamoxifen in postmenopausal women with early and advanced disease, combination treatment with goserelin plus an AI may provide optimal oestrogen blockade in premenopausal patients.

CONCLUSIONS

This review assesses the relative merits of chemotherapeutic and endocrine approaches for the treatment of early breast cancer, and summarises relevant ongoing clinical trials, with an emphasis on the premenopausal setting.

Aromatase inhibitors as adjuvant treatment of breast cancer

The development of the novel, third-generation aromatase inhibitors and inactivators represents a major improvement of endocrine therapy in breast cancer. Subsequent to phase III studies revealing clinical superiority of these drugs compared to conventional therapy as second- and first-line treatment for advanced disease, several randomised studies have found these compounds, administered either as monotherapy or in sequence with tamoxifen, to improve relapse-free survival compared to tamoxifen monotherapy in the adjuvant setting. Notably, we lack data on long-term follow-up with respect to efficacy as well as side effects, and there are currently no data on head to head comparisons between the different aromatase inhibitors. Several critical issues, like influences of treatment on bone and blood lipid profiles underline the need for long-term follow-up with respect to clinical events like bone fractures and cardiovascular events. Finally, we need data on cost-utility with respect to the different strategies as well as with respect to patient age and risk profile.

Adjuvant endocrine therapies for pre-/perimenopausal women

Endocrine therapy in the form of ovarian ablation was developed over a century ago. It remains nonetheless one of the most effective and most clearly targeted form of systemic therapy for breast cancer. Endocrine or hormonal therapy has an effect on virtually only those women whose tumors are positive for estrogen receptors (ER) and/or progesterone receptors (PgR). The presence of these steroid hormone receptors remains the most useful predictive factor in selecting therapy for breast cancer.

Adjuvant chemotherapy for breast cancer—“one fits all”?

Adjuvant breast cancer therapy and early diagnosis will improve breast cancer outcome. The Eurocare studies have demonstrated large differences in breast cancer incidence and mortality in different regions and countries and underlined the importance of access and quality in the management of early disease. So far, the very important survival gains by adjuvant therapy have been obtained by "one fits all"--like strategies, resulting in therapy in vain for many patients and unnecessary therapy for large cohorts. Present adjuvant strategies have focused on group statistical risk analysis, mainly using tumour stage, histological grade and receptor status. Five retrospective studies have revealed a worse outcome for patients receiving adjuvant chemotherapy without toxicity. In one of these studies the breast cancer survival was improved by 10% for patients who received grade 2/3 neutropenia; this is equivalent to the described survival gains by the addition of anthracyclines and taxanes to cyclophosphamide, methotrexate, 5-fluorouracil (CMF) combinations. Prospectively, this has been explored in the Scandinavian Breast Group (SBG) 9401-, SBG 2000-1- and presently in the SBG 2004-1 studies using tailored chemotherapy dosage strategies, aimed at avoiding under-dosage and diminishing acute side effects. For the future, we need several predictive factors for therapy, allowing better and more tailored therapy selections for individuals at risk. The present explorations of tumour RNA expression profiles are most likely to be useful in identifying therapy-predictive profiles for these individuals. Pharmacokinetic and pharmacodynamic data reveal marked differences in effect and tolerance of used drugs. The development of single nucleotide polymorphism technology are also likely to be important for optimising dosing strategies, aiming and increasing the effect, as well as decreasing toxicity. Taken together these strategies will be very different from the present "one fits all" concept.

Meta-analysis of individual patient data from randomized trials: a review of methods used in practice

BACKGROUND

Meta-analyses based on individual patient data (IPD) are regarded as the gold standard for systematic reviews. However, the methods used for analysing and presenting results from IPD meta-analyses have received little discussion.

METHODS

We review 44 IPD meta-analyses published during the years 1999-2001. We summarize whether they obtained all the data they sought, what types of approaches were used in the analysis, including assumptions of common or random effects, and how they examined the effects of covariates.

RESULTS

Twenty-four out of 44 analyses focused on time-to-event outcomes, and most analyses (28) estimated treatment effects within each trial and then combined the results assuming a common treatment effect across trials. Three analyses failed to stratify by trial, analysing the data is if they came from a single mega-trial. Only nine analyses used random effects methods. Covariate-treatment interactions were generally investigated by subgrouping patients. Seven of the meta-analyses included data from less than 80% of the randomized patients sought, but did not address the resulting potential biases.

CONCLUSIONS

Although IPD meta-analyses have many advantages in assessing the effects of health care, there are several aspects that could be further developed to make fuller use of the potential of these time-consuming projects. In particular, IPD could be used to more fully investigate the influence of covariates on heterogeneity of treatment effects, both within and between trials. The impact of heterogeneity, or use of random effects, are seldom discussed. There is thus considerable scope for enhancing the methods of analysis and presentation of IPD meta-analysis.

[GnRH agonists and breast pathology]

The discovery of hormone receptors and tamoxifen has revolutionized the management of breast cancer in women as the existence of oestrogen receptors has improved the response rate to hormone treatment from 30 to 50-70% with a further increase in this efficacy if there are also progesterone-positive receptors. LH-RH analogs induce medical castration. Their efficacy in combination with tamoxifen was demonstrated in terms of survival in pre-menopausal women with metastatic cancer. In the adjuvant situation, a meta-analysis of the 1980s demonstrated a benefit in terms of survival without relapse confirmed by more recent studies showing a reduction in the relative risk of relapse. On radiotherapy or ovariectomy, which are radical treatments, medical castration with LH-RH agonist analogs in combination with tamoxifen is therefore an alternative, reversible therapy for outpatients in particular now that a possible direct anti-tumor effect has been suggested by in vitro studies. Nevertheless, at present in France, Marketing Authorisation has not yet been granted for metastatic cancer.

The Role of Ovarian Ablation in the Management of Breast Cancer

In recent years the role of ovarian ablation as a therapeutic modality not only in the prevention but also in the treatment of breast cancer has reemerged after its initial use more than a century ago. BRCA-1 and BRCA-2 mutation carriers have an 85% lifetime risk of developing breast cancer. Bilateral salpingo-oophorectomy is effective in reducing the risk of developing breast cancer in both BRCA-1 and BRCA-2 mutation carriers by 50%. Tamoxifen reduces the risk of breast cancer in BRCA-2 mutation carriers, but not in BRCA-1 mutation carriers. Breast cancer arising in BRCA-1 mutation carriers is often estrogen receptor (ER) negative, unlike breast cancer developing in BRCA-2 mutation carriers. Sixty percent of premenopausal patients with breast cancer have ER-positive disease and 25% of breast cancer patients are premenopausal at diagnosis. The Early Breast Cancer Trialists' Collaborative Group review has shown ovarian ablation to be an effective adjuvant therapy for premenopausal breast cancer patients less than 50 years of age. But the Early Breast Cancer Trialists' overview also shows the benefit of ovarian ablation is uncertain if these patients also receive chemotherapy. Does the overview underestimate the efficacy of ovarian ablation? Some patients in these trials were ER negative. Most women less than 50 years of age who receive adjuvant chemotherapy become menopausal. So there is a need to test ovarian function suppression in the group who can benefit, or in other words, those that remain premenopausal after chemotherapy and have endocrine responsive breast cancer.

Analogues de la LHRH : leur utilisation dans le traitement du cancer du sein en situation métastatique et adjuvante☆

Breast cancer is often an estrogen-dependent disease. The primary goals of the treatment of breast carcinomas are multiple, depending on the situation in which the patients are treated. In adjuvant setting, the aims are to delete the time of relapse, to increase the overall survival, and to offer to the patients the best quality of life they may expect. Tamoxifen is the standard hormonal agent for premenopausal women with receptor-positive breast cancer. Recent data show an increasing role for aromatase inhibitors in postmenopausal women. In metastatic setting, the primary goals are improved quality of life and prolonged survival; effective therapies with minimal toxicity, such as endocrine therapy, are highly desirable and should be considered a primary option over chemotherapy for selected estrogen-receptor positive patients. Ovarian ablation has been worldwide used. Methods of irreversible ovarian ablation include surgical oophorectomy and ovarian irradiation. Potentially reversible castration can be medically accomplished using luteinizing hormone releasing hormone analogues (LHRH agonists). In the metastatic setting, ovarian ablation (induced by the use of LHRH agonists or by surgical ovarian ablation) and tamoxifen monotherapies produce comparable outcomes, and may be more effective when used together (combined estrogen blockade). In advanced breast cancer, the combination prolongs the progression-free survival and increases response rates and duration of response rate relative to the use of LHRH agonist alone. In the adjuvant setting, data suggest that ovarian ablation followed by tamoxifen produces similar results to those obtained with adjuvant chemotherapy in hormone-receptor positive breast cancer women. The value of combining these modalities remains unclear, but the addition of the LHRH analogue goserelin to standard treatment results in a significant benefit in terms of relapse-free and overall survival, especially for estrogen-receptor positive patients. Finally, considering the efficacy of the new aromatase inhibitors, the interest of combining these drugs with the LHRH analogues has yet to be defined, both for pre- and post-menopausal patients.

Meeting Highlights: International Expert Consensus on the Primary Therapy of Early Breast Cancer 2005

The ninth St Gallen (Switzerland) expert consensus meeting in January 2005 made a fundamental change in the algorithm for selection of adjuvant systemic therapy for early breast cancer. Rather than the earlier approach commencing with risk assessment, the Panel affirmed that the first consideration was endocrine responsiveness. Three categories were acknowledged: endocrine responsive, endocrine non-responsive and tumors of uncertain endocrine responsiveness. The three categories were further divided according to menopausal status. Only then did the Panel divide patients into low-, intermediate- and high-risk categories. It agreed that axillary lymph node involvement did not automatically define high risk. Intermediate risk included both node-negative disease (if some features of the primary tumor indicated elevated risk) and patients with one to three involved lymph nodes without additional high-risk features such as HER 2/neu gene overexpression. The Panel recommended that patients be offered chemotherapy for endocrine non-responsive disease; endocrine therapy as the primary therapy for endocrine responsive disease, adding chemotherapy for some intermediate- and all high-risk groups in this category; and both chemotherapy and endocrine therapy for all patients in the uncertain endocrine response category except those in the low-risk group.

Aromatase inhibition: translation into a successful therapeutic approach

The development of the novel third-generation aromatase inhibitors and inactivators for breast cancer treatment is one of the most successful contemporary achievements in cancer therapy. Parallel to studies evaluating toxicity and clinical efficacy in metastatic disease, the endocrine effects of multiple compounds were evaluated, leading to the identification of the highly potent third-generation aromatase inhibitors based on estrogen deprivation and aromatase inhibition in vivo. Thus, translational studies have been of vital importance identifying the unique characteristics of these compounds. Whereas first- and second-generation aromatase inhibitors inhibit estrogen synthesis in vivo by up to 90%, the third-generation compounds anastrozole, exemestane, and letrozole were found to cause > or =98% aromatase inhibition. This article summarizes and discusses the "translational research" that provided the background for the implementation of the third-generation aromatase inhibitors and inactivators into large clinical trials. The need for future translational research exploiting the mechanisms of resistance to these compounds for future improvement of endocrine therapy is emphasized.

The aromatase inhibitors in early breast cancer: who, when, and why?

The aromatase inhibitors deplete oestrogen by inhibiting aromatase, the enzyme that synthesises oestrogen from androgens. They are effective as therapies for breast cancer only in postmenopausal women whose tumours express oestrogen or progesterone receptors. As adjuvant therapy, tamoxifen and the aromatase inhibitors have similar efficacy in the first 5 years of treatment. Aromatase inhibitors can be used as an alternative to tamoxifen in women with symptomatic intolerance or a contraindication to tamoxifen. Early data suggest that switching to an aromatase inhibitor after 2-5 years of tamoxifen therapy is beneficial in women with high-risk disease. Aromatase inhibitors are associated with more hot flushes than placebo, but with fewer hot flushes, less endometrial toxicity and venous thromboembolism, and more arthralgia, myalgia and bone fracture than tamoxifen.

Systematic review of LHRH agonists for the adjuvant treatment of early breast cancer

There is increasing use of luteinising hormone-releasing hormone (LHRH) agonists in the adjuvant treatment of breast cancer (J. Clin. Oncol. 19(2) (2001) 343). However, few mature studies are available and there is uncertainty regarding the optimal use of these agents. We performed a systematic review to address the role of LHRH agonists in the adjuvant treatment of pre-menopausal women with early breast cancer. As ovarian suppression is unlikely to benefit women with ER-negative tumours, the review is limited to women with ER-positive disease. The objectives of this review were to address the following issues; the role of LHRH agonists compared to tamoxifen (TAM), LHRH agonists in place of chemotherapy and LHRH agonists integrated into chemo-hormonal regimens. We identified 11 randomised trials. In three trials, adjuvant suppression of ovarian function using LHRH agonists, with or without TAM, had similar benefits at 5-6 years follow-up in terms of disease-free survival (DFS) and overall survival (OS) to adjuvant CMF chemotherapy (J. Clin. Oncol 20(24) (2002) 4628; J. Natl. Cancer Inst. 95(24) (2003) 1833; Anticancer Res. 22 (2002) 2325; In: San Antonio Breast Cancer Symposium, San Antonio, TX, 2003, Abstr 40). These findings suggest that ovarian suppression using LHRH agonists (+/-TAM) is a reasonable alternative to CMF chemotherapy in women with oestrogen receptor (ER) positive tumours. The role of chemotherapy in addition to LHRH agonists is not clearly defined and mature results of four trials are awaited (J. Clin. Oncol. 20(24) (2002) 4621; J. Clin. Oncol. 18(14) (2000) 2718; Proc. Am. Soc. Clin. Oncol. 2000, Abstr 279; Proc. Am. Soc. Clin. Oncol. 20 (2001) Abstr 104; Proc. Am. Soc. Clin. Oncol. 2001, Abstr. 1777). Data is also inadequate at the time of publication to inform decisions about the efficacy of LHRH agonists in comparison with TAM for the treatment of ER-positive early breast cancer (Proc. Am. Soc. Clin. Oncol. 21 (2001) Abstr. 103; Eur. J. Surg. Oncol. 28(5) (2002) 505; Proc. Am. Soc. Clin. Oncol. 22 (2003), Abstr. 15).

Endocrinology and hormone therapy in breast cancer: endocrine therapy in premenopausal women

Endocrine therapy remains important in premenopausal women with hormone receptor positive breast cancer. Ovarian ablation, used alone, is effective in delaying recurrence and increasing survival in such women. When added to chemotherapy, it is less clear that it is effective perhaps because of the endocrine ablative effect of chemotherapy. Trials comparing ovarian ablation with or without tamoxifen to CMF-type chemotherapy suggest that the endocrine therapy is equivalent to or better than this chemotherapy in women whose tumors have estrogen and/or progesterone receptor. Tamoxifen is also effective in preventing recurrence and prolonging survival in the adjuvant setting in premenopausal women. While most of the available data deals with tamoxifen given alone, it appears to have a similar beneficial effect when added to chemotherapy in the premenopausal adjuvant setting. Adjuvant aromatase inhibitors should not be used in premenopausal women.

The choice of systemic adjuvant therapy in receptor-positive early breast cancer

Patients with endocrine-responsive breast cancer represent a distinct population for which tailored adjuvant treatments are needed. Endocrine therapy is mandatory for this population. For premenopausal patients, ovarian ablation or tamoxifen can be recommended; the combination of both, as well as the combination of ovarian ablation and aromatase inhibitors is under investigation. For postmenopausal patients, tamoxifen for 5 years is the 'standard of care'. Anastrozole can be recommended for patients with a contraindication to tamoxifen. The addition of 5 years of letrozole after 5 years of tamoxifen has yielded benefits in terms of disease-free survival. The sequential use of tamoxifen and exemestane was superior to tamoxifen for 5 years. However, in both studies, long-term toxicity is still not fully evaluated. The addition of chemotherapy to endocrine treatment can be recommended for patients at high risk of relapse and in young patients. Chemotherapy should consist of 3-6 cycles of cyclophosphamide, methotrexate, 5-fluorouracil or of an anthracycline-containing regimen. The addition of taxanes cannot be routinely recommended in this population. Endocrine treatment should start after completion of chemotherapy.

Bone mineral density among premenopausal women with early breast cancer in a randomized trial of adjuvant endocrine therapy

PURPOSE

To examine the effects on bone mineral density of 2 years of treatment with a luteinizing hormone-releasing hormone (LHRH) agonist alone or in combination with tamoxifen or tamoxifen alone in premenopausal breast cancer.

PATIENTS AND METHODS

We recruited 89 women from two centers in Stockholm participating in a randomized multicenter trial of three different endocrine approaches in the adjuvant setting (Zoladex in Premenopausal Patients Trial). The women were assigned to receive the LHRH agonist goserelin with or without tamoxifen, tamoxifen alone, or no endocrine therapy. The treatment was given for 2 years. We measured total-body bone density before start of treatment and at 12, 24, and 36 months.

RESULTS

After 2 years of treatment, there was a significant loss of bone mineral density (mean change, -5%; P <.001) in the women receiving goserelin alone. The combined goserelin and tamoxifen treatment, as well as tamoxifen alone, resulted in a lesser but statistically significant decline in bone mineral density (mean change, -1.4%; P =.02; and -1.5%; P <.001). One year after cessation of treatment, the goserelin group alone showed a partial recovery from bone loss (mean change, 1.5%; P =.02).

CONCLUSION

Two years of ovarian ablation from goserelin treatment caused a significant reduction in bone mineral density but there was a partial recovery from the bone loss 1 year after cessation of treatment. The addition of tamoxifen seems to partially counteract the demineralizing effects of goserelin.

What Is the Role of Ovarian Ablation in the Management of Primary and Metastatic Breast Cancer Today?

Ovarian ablation has been used for more than a century in the treatment of breast cancer. Methods of irreversible ovarian ablation include surgical oophorectomy and ovarian irradiation. Potentially reversible castration can be accomplished medically using luteinizing hormone releasing hormone (LHRH) analogues. In addition, cytotoxic chemotherapy unpredictably produces amenorrhea and primary ovarian failure in 10%-95% of premenopausal women as a function of patient age, cumulative dose, and the specific agents used. In the metastatic setting, ovarian ablation and tamoxifen monotherapies produce comparable outcomes and may be more effective when used together. While many early adjuvant trials of ovarian ablation were methodologically flawed, a more recent meta-analysis by the Early Breast Cancer Trialists' Collaborative Group of 12 properly designed randomized trials found significantly greater disease-free and overall survival rates for women under the age of 50, regardless of nodal status, receiving ovarian ablation as a single adjuvant therapy. Several important issues regarding the role of ovarian ablation in the treatment of breast cancer remain unresolved. Data suggest that ovarian ablation followed by some years of tamoxifen produces similar results to those seen with adjuvant chemotherapy in women with hormone-receptor positive breast cancer; however, the value of combining these modalities is still unclear. Other areas of ongoing investigation include the appropriate duration of therapy with LHRH analogues in the adjuvant setting, the long-term sequelae of ovarian suppression among young breast cancer survivors, and refinement of the population most likely to benefit from ovarian ablation or suppression.

LH-RH agonists offer very good protection against the adverse gynaecological effects induced by tamoxifen

This study was initiated to evaluate the efficacy of luteinizing hormone-releasing hormone (LH-RH) agonists in protecting premenopausal patients against the adverse gynaecological effects induced by tamoxifen. Between January 1998 and January 2000, 85 premenopausal breast cancer patients were included in this prospective study. All were to receive LH-RH agonists and tamoxifen for a minimum of two years. All patients underwent a pretreatment gynaecological evaluation and annual follow-up. Bone density was also measured at the start of treatment and then after 2, 3 and 4 years. Pretreatment evaluation revealed 2 polyps. At one and two years of follow-up, no abnormal symptoms were noted and echographic findings were normal. At three years of follow-up, a polyp associated with adnexal masses was discovered. Histology revealed ovarian and endometrial metastases of infiltrating lobular breast carcinoma. Bone density evaluation after 2, 3 and 4 years of treatment showed no significant bone loss. LH-RH agonists offer safe protection against the gynaecological side-effects of tamoxifen in premenopausal breast cancer patients.

The curability of breast cancer and the treatment of advanced disease

Breast cancer represents a major health problem, with more than 1,000,000 new cases and 370,000 deaths yearly worldwide. In the last decade, in spite of an increasing incidence, breast cancer mortality has been declining in the majority of developed countries. This is the combined result of better education, widespread screening programmes and more efficacious adjuvant treatments. Better knowledge of breast cancer biology now allows the cosmetic, physical and psychological consequences of radical mastectomy to be spared in the majority of breast cancer patients. Use of the sentinel node technique is rapidly expanding and this will further reduce the extent and the consequences of surgery. Several clinico-pathological factors are used to discriminate between patients at low (<10%), average (10-40%) and high risk of relapse. Nodal status, tumour size, tumour grade and age are accepted universally as important factors to define risk categories. Newer factors such as uPA/PAI-1, HERer2-neu, proliferative indices and gene expression profile are promising and will allow better discrimination between patients at different risk. Endocrine manipulation with tamoxifen, ovarian ablation or both is the preferred option in the case of endocrine-responsive tumours. Tamoxifen administered for 5 years is the standard treatment for postmenopausal patients; tamoxifen plus ovarian ablation is more effective than tamoxifen alone for premenopausal women. Recent data demonstrate that, for postmenopausal patients, the aromatase inhibitors are superior to tamoxifen, with a different safety profile. At present, anastrozole can be used in the adjuvant setting in cases of tamoxifen intolerance or toxicity. Chemotherapy is the treatment of choice for steroid receptor-negative tumours. Polychemotherapy is superior to single agents and anthracycline-containing regimens are superior to CMF. Six courses of FEC or FAC or the sequential administration of four doses of anthracycline followed by four of CMF are the recommended regimens. New regimens including the taxanes have produced a further improvement in risk reduction and are reasonable therapeutic options. The taxanes have been approved for adjuvant therapy in the USA, while European approval is pending. Combined endocrine-chemotherapy is the standard adjuvant treatment in high-risk patients with endocrine-responsive tumours. Endocrine manipulation is usually administered after completion of the chemotherapy programme. For HER2-neu overexpressing tumours, several rapidly accruing trials are exploring the potential additive effect of trastuzumab, a monoclonal antibody directed against the extramembrane portion of the HER2 receptor. Primary chemotherapy is increasingly used in the treatment of locally advanced and operable breast cancer, with increased rates of breast-conserving surgery. A proportion of patients achieve a pathological complete response and these patients have significantly better long-term outcomes. Twenty-five to forty percent of breast cancer patients develop distant metastases. At this stage the disease is incurable; however, treatments can assure a significant prolongation of survival, symptomatic control and maintenance of quality of life. In the case of hormone receptor positivity and in the absence of visceral, life-threatening disease, endocrine manipulation is the treatment of choice. Active treatments include tamoxifen, ovarian ablation, aromatase inhibitors, pure anti-oestrogens and progestins. Aromatase inhibitors are the most active agents, but the choice and the sequence of endocrine therapies are also dictated by prior adjuvant treatment. Chemotherapy has to be preferred in cases of receptor-negative tumours, acquired resistance to hormones and aggressive visceral disease. Combination regimens are usually associated with higher response rates and sometimes survival prolongation, and this approach should be recommended in young patients with good performance status and visceral disease. On the other hand, single agents have a better tolerability profile and should be tand should be the treatment of choice when a careful balance between activity and tolerability is needed. For HER2-neu positive tumours, the combination of trastuzumab and chemotherapy is significantly superior to chemotherapy alone in terms of both response rates and survival. Other useful palliative treatments include bisphosphonates for the control of metastatic bone disease and radiotherapy for painful bone lesions or local relapses.

Clinical and endocrine data for goserelin plus anastrozole as second-line endocrine therapy for premenopausal advanced breast cancer

A total of 16 premenopausal women with metastatic breast cancer (N=13) or locally advanced primary breast cancer (N=3) were treated with a combination of a gonadotropin-releasing hormone agonist goserelin, and a selective aromatase inhibitor anastrozole. All had previously been treated with goserelin and tamoxifen. In all, 12 patients (75%) achieved objective response or durable stable disease at 6 months, with a median duration of remission of 17+ months (range 6–47 months). Four patients still have clinical benefit. Introduction of goserelin and tamoxifen resulted in an 89% reduction in mean oestradiol levels (pretreatment vs 6 months=224 vs 24 pmol l⁻¹) (P<0.0001). Substitution of tamoxifen by anastrozole on progression resulted in a further 76% fall (to 6 pmol l⁻¹ at 3 months) (P<0.0001). Treatment with goserelin and tamoxifen led to a 90% fall in the mean follicle-stimulating hormone (P<0.001). This was reversed once therapy was changed to goserelin and anastrozole. A similar initial reduction was seen in the mean luteinising hormone levels, but substitution of tamoxifen by anastrozole on progression resulted in no significant change. Goserelin and tamoxifen did not lead to any significant change in testosterone and androstenedione levels. The combined use of goserelin and anastrozole as second-line endocrine therapy produces a significant clinical response of worthwhile duration, with demonstrable endocrine changes, in premenopausal women with advanced breast cancer, and offers them another therapeutic option. Further studies involving more patients and longer follow-up are indicated.

Oestrogen suppression--lessons from clinical studies

In few, if any, areas of cancer research has "translational research" played a role such as the one it has played in the development of endocrine therapy. Thus, much of the understanding of the mechanisms of action of different therapies has been achieved by developing novel hypotheses based on clinical observations. Ovarian ablation was developed as an empirical therapy long before characterization of oestrogen disposition or detection of the oestrogen receptor. The first-generation aromatase inhibitor, aminoglutethimide, was implemented as a strategy to achieve a 'medical adrenalectomy' and was discovered as an aromatase inhibitor subsequent to clinical observations. Currently, observations such as the lack of cross-resistance between aromatase inhibitors and inactivators and the diverse effects from combined therapy using tamoxifen in concert with hormonal suppression in pre- and post-menopausals are provoking interesting questions for further research.