Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278488 (metastatic breast cancer)
 7,812 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tamoxifen (TAM) is widely used as therapy in early breast cancer and first-line endocrine therapy in metastatic disease. Despite this therapy, many patients relapse and an important question is: What is the preferred sequence of endocrine therapies in metastatic breast cancer (MBC). While treatment with oophorectomy, aminoglutethimide or progestins have been a logical choice after failure to Tamoxifen recent research has extended the options for endocrine therapy of MBC. New selective aromatase inhibitors (AI) are now in clinical use. The first commercially available of these inhibitors is LENTARON. The active ingredient of LENTARON is a steroidal compound 4-OH-androstenedione: Formestane. It is presented as a depot formulation and applied as an i.m. injection of 250 mg every second week. Previous findings from phase II trials have indicated similar activity as other endocrine treatment modalities. Clinical investigations in properly conducted phase III trials have revealed that the efficacy of LENTARON matches the results which can be obtained with TAM and Megace in trials of first and second-line endocrine therapy. Fifty-four and 51% of MBC patients, respectively, did benefit from therapy with LENTARON in these phase III trials by achieving objective responses or stable disease. Moreover, similar overall survival was seen. The systemic tolerability of LENTARON is comparable to that of TAM, and LENTARON seems less systemically toxic than Megace. Local side effects occured in approximately 7% of the patients giving rise mainly to pain or inflammation at the injection site. In elderly patients, LENTARON therapy assures compliance and no interference with other oral medications has been observed. In conclusion, since the endocrine treatment modalities are comparable in terms of efficacy the optimal sequence of these treatments is based upon differences in tolerability. Patients previously treated with Tamoxifen and with a high probability of a further endocrine response could preferably be treated with a selective AI like LENTARON as second-line endocrine therapy followed by a progestin upon progression in responders.
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PMID:Proper sequence of endocrine therapies in advanced breast cancer. 914 64

The introduction of new drugs may offer significant hope for improvement in the treatment of breast cancer. They include new cytotoxic agents such as Taxanes, Topoisomerase inhibitor, MDR modulator, new hormone such as 3rd generation nonsteroidal aromatase inhibitor, pure antiestrogen for patients with refractory metastatic breast cancer and new bisphosphonates for those who have metastases to bone. Therefore, some reports evaluating such new drugs were reviewed. Japanese studies revealed response rate of Taxanes in the treatment of metastatic breast cancer as follows; Six out of 22 (27%) with 1 CR for 24 hours infusion, 21 out of 52 (34%) with 2 CR for 3 hours infusion of paclitaxel respectively, 21 out of 31 (41%) with 2 CR for 1 hour infusion, and 32 out of 72 (44%) with 5 CR for 1 hour infusion of Docetaxel, In addition, the MTD of the combination was reached at dose level with 60 mg/sqm of Docetaxel and 400 mg/sqm of cyclophosphamide. As regards hormone therapy, thirty four out of 176 (19%) with 5 CR were observed in phase II study of Fadrozol but results from the phase II study of 3rd generation aromatase inhibitor is not yet accomplished in Japan. However, any european reports did not show a difference in response rate in patients with tamoxifen refractory breast cancer between newer aromatase inhibitor and megasterol, and a good choice of hormones in the treatment of metastatic breast cancer appears to be difficult.
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PMID:[New drugs in metastatic breast cancer--1997]. 935 Feb 35

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.
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PMID:Use of aromatase inhibitors in postmenopausal women with advanced breast cancer. 936 69

Hormonotherapy in metastatic breast cancer is actually performed using 3 therapeutic classes: antiestrogen as tamoxifen (TAM), progestins, megestrol acetate (MA) and medroxyprogesterone acetate (MPA), aromatase-inhibitors as aminoglutethimide (AG). We investigated therapeutic efficacy of progestins compared to other hormonotherapies in case of breast cancer with bone metastasis. In a literature review, we found ten randomized trials comparing: MPA versus AG, MPA versus MA, MPA versus TAM, MA versus AG versus TAM. The results show an advantage on the response rate using MPA; the usual dose was 900-2,000 mg daily. MPA mode of action can explain these results since they combine gestagenic, androgenics and glucocorticoid effects.
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PMID:[Progestational agents and bone metastasis in breast cancer]. 943 12

The role of anastrozole, a new selective aromatase inhibitor, in treating hormone-responsive metastatic breast cancer is discussed. Treatment options for hormone-dependent breast cancer focus on interfering with the endocrine system in an attempt to modify the effects of estrogen. Tamoxifen is the drug of choice for primary endocrine therapy, but there is a need for agents with similar or greater efficacy and better tolerability. Anastrozole inhibits the conversion of androgens to estrogens by aromatase. Bioavailability studies have demonstrated almost complete absorption of anastrozole after oral administration. The drug's terminal half-life after multiple doses is 50 hours. Anastrozole is cleared principally by the liver. Clinical trials comparing anastrozole with megestrol acetate demonstrated no significant differences in clinical efficacy, although a follow-up study revealed a longer median overall survival rate in patients receiving anastrozole. The drug is well tolerated. Among the most frequently reported adverse effects are asthenia, hot flashes, headache, and back pain. The recommended dosage is 1 mg daily. The average wholesale cost of month's supply of anastrozole is $187.20, compared with approximately $100 for generic megestrol acetate or aminoglutethimide plus hydrocortisone. Although anastrozole will likely become the preferred second-line agent in the treatment of postmenopausal breast cancer in patients with disease progression after tamoxifen therapy, it is not a therapeutic alternative to aminoglutethimide on the basis of approved indications. Anastrozole and other aromatase inhibitors may have multiple applications in treating hormone-responsive breast cancer.
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PMID:Anastrozole: a selective aromatase inhibitor for the treatment of breast cancer. 952 27

The new generation of potent steroidal and nonsteroidal inhibitors of the enzyme aromatase act by decreasing estrogen production throughout the body in postmenopausal women. The most potent of these agents may also inhibit estrogen synthesis within metastatic breast cancer tissue. The newly developed, orally administered, nonsteroidal competitive inhibitors, such as anastrozole (Arimidex), letrozole (Femara), and vorozole (Rizivor), are a thousand times more potent inhibitors of aromatase than is aminoglutethimide. Furthermore, these agents are highly selective. In several large randomized trials, the new inhibitors produced similar response rates as megestrol acetate (160 mg/d) in postmenopausal women with hormone-dependent breast cancer, but showed a trend toward improved response duration and survival. They also produced less weight gain and fewer cardiovascular and thromboembolic side effects. In addition, letrozole proved superior to aminoglutethimide in another randomized trial. Both anastrozole (1.0 mg/d) and letrozole (2.5 mg/d) have now been approved as second-line treatment for hormone-dependent breast cancer in postmenopausal women in whom disease has progressed following tamoxifen treatment. Either drug should replace the routine use of megestrol acetate in this setting. Ongoing clinical studies are comparing anastrozole and letrozole to antiestrogens as first-line endocrine therapy for metastatic breast cancer. Other trials will study the possible roles of these compounds as adjuvant therapy and chemoprevention for breast cancer.
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PMID:Emerging role of aromatase inhibitors in the treatment of breast cancer. 955 89

Letrozole (Femara) is a nonsteroidal aromatase inhibitor that is approximately 10,000 times as potent as aminoglutethimide in vivo. Two pivotal multinational phase III trials have compared letrozole (0.5 and 2.5 mg/d) against megestrol acetate and aminoglutethimide, respectively, in patients with locally advanced or metastatic breast cancer. The letrozole vs megestrol acetate trial showed the superiority of letrozole (2.5 mg/d) over megestrol acetate with respect to response rate, response duration, duration of overall clinical benefit (complete response plus partial response plus stable disease > or = 6 months), time to progression, and time to treatment failure. The letrozole-treated patients also showed a nonsignificant trend toward better survival. In the letrozole vs aminoglutethimide trial, letrozole (2.5 mg/d) was significantly superior in terms of duration of overall clinical benefit and survival. There were also strong trends favoring letrozole with regard to objective response rate and duration of response. Unexpectedly, both trials demonstrated a dose-response effect for 2.5 mg of letrozole over 0.5 mg in terms of response and overall survival. This finding raises the possibility that intratumoral aromatase suppression may be more relevant in breast cancer therapy than are plasma estrogen levels.
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PMID:Pivotal trials of letrozole: a new aromatase inhibitor. 955 91

Recent trials comparing single-agent vs combination therapy in metastatic breast cancer suggest that it may be time to reconsider the belief that combination chemotherapy is the gold standard of treatment. Based on the limited randomized trial data available to date, high-dose chemotherapy with stem-cell rescue should not be viewed as "state-of-the art" treatment for metastatic disease and should be used only in the context of clinical trials. Recent trials have explored the optimal dosing and scheduling of the taxanes, as well as the possible role of these agents in combination regimens. Capecitabine (Xeloda), a new oral fluoropyrimidine, appears to be comparable in efficacy to CMF (cyclophosphamide, methotrexate, and fluorouracil), and preclinical data suggest possible synergy between this agent and the taxanes. Other promising agents under study include liposome-encapsulated doxorubicin (TLCD-99), an immunoconjugate linking a chimeric human/mouse monoclonal antibody to doxorubicin molecules; MTA (LY231514), a multitargeted antifolate; and marimistat, a broad-spectrum matrix metalloproteinase inhibitor. Tamoxifen (Nolvadex) remains the most important hormonal agent, but new antiestrogens and selective estrogen receptor modulators (SERMs) may provide alternatives. The potential role of new aromatase inhibitors as first-line hormonal agents requires further study. Finally, the possible synergy between trastuzumab (Herceptin), a recombinant humanized monoclonal antibody to the HER-2/neu protein, and paclitaxel (Taxol) is being studied in two clinical trials.
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PMID:Update on the management of advanced breast cancer. 1035 85

Three new aromatase inhibitors have recently completed phase III evaluation as treatment of metastatic breast cancer in post-menopausal women whose disease has progressed despite tamoxifen therapy: anastrozole (ARIMIDEX, Zeneca), letrozole (FEMARA, Novartis) and vorozole (RIVIZOR, Janssen). All belong to the third generation of non-steroidal aromatase inhibitors, and each is superior to previous generations in terms of potency and selectivity. The trials that have been performed compare each agent to megestrol acetate, and letrozole and vorozole to aminoglutethimide. Although the studies are not directly comparable due to differing study designs and patient populations, it has been demonstrated each of these drugs provides single agent, once-daily, oral palliation of hormone-responsive, post-menopausal metastatic breast cancer. Letrozole is clearly more effective than megestrol acetate, and anastrozole and vorozole are possibly so. All three are better tolerated than the progestin, particularly in terms of weight gain. Both letrozole and vorozole are significantly more effective, and better tolerated than aminoglutethimide. Overall, this most recent generation of aromatase inhibitors is a clear improvement on our current standard second-line therapies. In 1999, tamoxifen remains the first choice in the hormonal therapy of breast cancer. Following tamoxifen failure, the optimal second-line hormonal therapy remains undefined, but aminoglutethimide and megestrol acetate are no longer optimal therapy in this setting. The third-generation non-steroidal aromatase inhibitors must now be compared to each other, to the steroidal aromatase inhibitors, to the pure anti-oestrogens, and to tamoxifen.
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PMID:The third-generation non-steroidal aromatase inhibitors: a review of their clinical benefits in the second-line hormonal treatment of advanced breast cancer. 1037 Jul 78

The goals of this clinical trial involving postmenopausal women with metastatic breast cancer were to: (a) examine the effects of letrozole on tamoxifen (TAM) pharmacokinetics; (b) examine estrogen suppression in patients receiving TAM plus letrozole; and (c) evaluate tolerability, toxicity, objective response, and time to progression for the combination. Postmenopausal women with measurable or evaluable metastatic breast cancer received TAM (20 mg daily) for 6 weeks, and then letrozole (2.5 mg daily) was added. To examine for any effect of letrozole on the levels of TAM and two metabolites [N-desmethyl-TAM and 4-hydroxy-TAM], serum samples were obtained at 6, 12, 18, and 24 weeks. To examine for aromatase inhibition, serum samples were obtained before treatment and at 6, 12, 18, and 24 weeks for estradiol, estrone (E1) E1 sulfate, and sex hormone-binding globulin. A total of 34 patients were entered on this trial, and 23 patients were still on study at week 24, 18 of whom had blood samples available at both week 6 and week 24. The 95% confidence interval for the mean difference between levels at week 24 and levels at week 6 was -34 to 15 ng/ml for TAM, -35 to 45 ng/ml for N-desmethyl-TAM, and -1 to 2 for 4-hydroxy-TAM. For estradiol, a significant decrease (median, 88.5%; range, 73.7-95.2%) was identified after 6 weeks of letrozole, which was maintained for an additional 12 weeks. Similar significant reductions were identified for E1. E1 sulfate levels increased after 6 weeks of TAM alone but then decreased significantly after the addition of letrozole. Sex hormone-binding globulin levels were significantly elevated after 6 weeks of TAM alone and remained elevated after the addition of letrozole. Six of the 34 patients (17.6%) achieved an objective response (95% confidence interval, 6.8-34.5%), with a median time to disease progression of 7.6 months. There was no indication of a systematic decrease in TAM, N-desmethyl-TAM, or 4-hydroxy-TAM after the additional of letrozole. Estrogen suppression induced by letrozole was substantial despite the concomitant administration of TAM. The antitumor effect of TAM plus letrozole was less than expected.
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PMID:Evaluation of tamoxifen plus letrozole with assessment of pharmacokinetic interaction in postmenopausal women with metastatic breast cancer. 1043 63


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