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Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tamoxifen is commonly used in the management of patients with breast cancer. Clinical trials of tamoxifen involving over 75,000 patients demonstrate an improved recurrence-free and overall survival benefit in both pre- and post-menopausal women. Large-scale trials also are evaluating the role of tamoxifen as a chemopreventive agent in women considered to be at high risk for developing breast cancer based on family history. Endometrial cancer is an uncommon complication of tamoxifen therapy. Since the majority of these cancers will be detected at an early stage when they are highly curable, however, the overall benefit of tamoxifen treatment in breast cancer patients outweighs this risk. All women receiving tamoxifen who have a uterus should undergo regular gynecologic examinations.
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PMID:Tamoxifen and Endometrial Cancer. 1079 70

Antioestrogen therapy is currently receiving renewed interest for several reasons. Tamoxifen was introduced in the treatment of metastatic breast cancer more than three decades ago. The drug significantly reduces long term mortality and also reduces the risk of contralateral tumours when administered in early breast cancer. Five years of tamoxifen is now standard in adjuvant endocrine therapy, and the drug is currently being evaluated for breast cancer prevention. Despite this, several aspects regarding the pharmacology of the drug are still unclear, and the scientific rationale for dose selection has recently been challenged. Several novel antioestrogen compounds, called selective oestrogen receptor modifiers (SERMs), express selective oestrogen agonistic or antagonistic properties depending on the organ or test system evaluated. Some of these drugs, like raloxifene, do not seem to promote the development of endometrial cancer, although they still have selected oestrogen-like beneficial effects. This paper reviews the pharmacologic and the pharmacokinetic aspects of the different SERMs with particular emphasis on their potential use in therapy and prevention of breast cancer.
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PMID:Selective oestrogen receptor modifiers (SERMs) and breast cancer therapy. 1081 62

Tamoxifen has been used for the treatment of breast cancer since the 1970s, but is considered a carcinogen because it has been linked to liver cancer in rats and an increased risk of endometrial cancer in patients. In rats, DNA adducts appear to be responsible for carcinogenesis, but their contribution to carcinogenesis in humans is not clear. FC-1271a and toremifene are mixed antiestrogens similar to tamoxifen. In order to compare the genotoxicity of these different triphenylethylenes, we treated mice for 28 days with 50 mg/kg of either tamoxifen, toremifene, FC- 1271 a or vehicle control. DNA from liver and uterus was assayed by standard 32P-postlabeling and thin layer chromatography for the presence of DNA adducts. Two methods of drug administration (oral and subcutaneous) and two strains of mice were compared and the plasma and tissue concentrations of the drugs and three metabolites of tamoxifen and toremifene were determined. Regardless of the conditions, only tamoxifen-treated mice showed DNA adducts in the liver. Adduct levels did not correlate with drug or metabolite levels and adducts were present even when drug was not detectable. Mice were also treated orally with either 50, 100, or 200 mg/kg of drug for 7 days. Again, adducts were found only in liver tissue of mice treated with tamoxifen, and adduct levels were dose-dependent. In conclusion, the chlorinated triphenylethylene FC-1271a did not cause DNA adducts under various conditions in mice, suggesting a low carcinogenic potential.
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PMID:Genotoxic effects of the novel mixed antiestrogen FC-1271a in comparison to tamoxifen and toremifene. 1084 10

Selective oestrogen receptor modulators (SERMs) are structurally diverse non-steroidal compounds that bind to oestrogen receptors and produce oestrogen agonist effects in some tissues and oestrogen antagonist effects in others. SERMs are being evaluated for a number of oestrogen-related diseases, including post-menopausal osteoporosis, hormone-dependent cancers, and cardiovascular disease. Several compounds that exhibit a SERM profile are currently available for clinical use, including clomiphene, tamoxifen, and toremifene (which are triphenylethylenes) and raloxifene (a benzothiophene). Clomiphene is used for the induction of ovulation in sub-fertile women attempting pregnancy. Tamoxifen and toremifene are both used to treat breast cancer. Tamoxifen may have beneficial effects on bone mineral density and serum lipids. The effects of toremifene on serum lipids are similar to that of tamoxifen. Both compounds have stimulatory effects on the endometrium. Raloxifene, indicated for the treatment and prevention of post-menopausal osteoporosis, has beneficial effects on bone mineral density and serum lipids, but does not increase the risk of endometrial hyperplasia or endometrial cancer. Recently, raloxifene was shown to reduce the incidence of vertebral fractures in otherwise healthy women with osteoporosis; in the same study, a reduced incidence of breast cancer was also observed. Similar to oestrogens, SERMs increase the incidence of venous thromboembolism. Several newer compounds that exhibit a SERM profile are also in clinical development, including other triphenylethylenes (droloxifene, idoxifene) and benzothiophenes (LY353381.HCl), benzopyrans (EM-800), and naphthalenes (CP-336,156).
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PMID:A pharmacological review of selective oestrogen receptor modulators. 1087 66

Tamoxifen is a nonsteroidal antiestrogen that has become the frontline endocrine therapy for all stages of breast cancer. The drug is the only single-agent therapy that, when used in an adjuvant fashion, produces a survival advantage in postmenopausal women. Survival is longer when the estrogen receptor content of the primary tumor is higher, although receptor-poor patients still have a survival advantage from adjuvant tamoxifen equivalent to that noted with combination chemotherapy. The added advantages of tamoxifen are a maintenance of bone density and a decrease in fatal myocardial infarction. Although side effects from tamoxifen are few, patients must be examined for preexisting endometrial carcinoma before beginning drug use. Tamoxifen does not prevent the growth of endometrial tumors. Spotting and vaginal bleeding in postmenopausal patients taking tamoxifen should be followed up with a thorough gynecological examination. The incidence rate of endometrial cancer for tamoxifen-treated patients is 2 per 1000 patients per year. More than 80% of detected endometrial tumors are stage 1 disease and can be cured by hysterectomy.
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PMID:Long-term Tamoxifen Therapy for the Treatment of Breast Cancer. 1088 88

The rationale for clinical trials of antiestrogens for prevention of breast cancer, potential concerns with antiestrogens, and clinical trials of antiestrogens for breast cancer prevention are discussed. Extensive preclinical evidence supports clinical investigation and use of tamoxifen for preventing breast cancer. The efficacy of tamoxifen in the treatment of advanced breast cancer and as adjuvant therapy has further strengthened the rationale for use in prevention. Tamoxifen is well tolerated and, like raloxifene, has been associated with non-cancer-related benefits. The major concerns with tamoxifen are an increased risk of thromboembolic events and endometrial cancer and an association with ocular disorders. Little is known about the long-term safety of raloxifene. Three randomized, double-blind, placebo-controlled clinical trials of tamoxifen 20 mg (as the citrate) daily for the prevention of breast cancer and one post hoc analysis and a literature review examining the effect of raloxifene on breast cancer risk (as a secondary endpoint) have been published. In one of the three trials of tamoxifen, the rate of invasive breast cancer was reduced 49%; in the other two trials, no reduction in breast cancer was found. Raloxifene apparently reduced the frequency of breast cancer. On the basis of the positive tamoxifen trial, tamoxifen can be offered to women with a five-year projected risk of breast cancer of > or = 1.67%, as determined by the Gail model. Risks and benefits should be evaluated for each patient. Tamoxifen may offer some women protection against breast cancer. Raloxifene may also have a preventive role, but more study is needed.
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PMID:Safety and efficacy of antiestrogens for prevention of breast cancer. 1091 21

Tamoxifen is the endocrine treatment of choice for all stages of estrogen receptor (ER)-positive breast cancer, and it is the first drug approved to reduce the incidence of breast cancer in high-risk women. Unfortunately, tamoxifen also possesses some estrogen-like effects in the uterus that cause a modest increase in the risk of endometrial cancer. GW5638 is a tamoxifen derivative with a novel carboxylic acid side chain with no uterotropic activity in the rat (Willson et al., J Med Chem, 1994, 37:1550-1552). We have compared and contrasted the actions of 4-hydroxytamoxifen (4-OHT, the active metabolite of tamoxifen) with GW7604 [the presumed metabolite of GW5638 in breast (MCF-7) and endometrial (ECC-1) cell lines in vitro]. GW7604 did not cause the growth of ECC-1 cells at any concentration (10(-11)-10(-6) M), but 4-OHT was weakly estrogen-like at low concentrations (10(-11)-10(-10) M). Compounds (10(-7) M) blocked the growth promoting action of estradiol (10(-10) M) in both ECC-1 and MCF-7 cells. Western blotting was used to show that GW7604 and raloxifene did not affect ER levels significantly, compared with controls, in MCF-7 cells; whereas the pure antiestrogen ICI182,780 decreased ER levels (P < 0.05). An assay system was used that can classify compounds into tamoxifen-like, raloxifene-like, or pure antiestrogens. The assay depends on the activation of the transforming growth factor alpha (TGFalpha) gene in situ by wild-type or D351Y mutant ER stably transfected into MDA-MB-231 cells (MacGregor-Schafer et al., Cancer Res, 1999, 59:4308-4313). GW7604 inhibited both estradiol (10(-9) M) and 4-OHT (10(-8), 10(-7) M) induction of TGFalpha in a concentration related manner (10(-9)-10(-6) M). GW7604 and raloxifene stimulated TGFalpha with the D351Y ER. In contrast, ICI 182,780 (10(-6) M) did not initiate TGFalpha and blocked the induction of TGFalpha with GW7604, raloxifene, and 4-OHT in D351Y-transfected cells. Using computer-assisted molecular models of ER complexes, we found that the antiestrogenic side chain of 4-OHT weakly interacted with the surface amino acid 351 (aspartate), but the carboxylic acid of GW7604 caused a strong repulsion of aspartate 351. We propose that GW7604 is less estrogen-like than 4-OHT, because it disrupts the surface charge around aa351 required for coactivator docking in the 4-OHT:ER complex. This charge is restored in the D351Y ER, thus converting GW7604 from an antiestrogen to an estrogen-like molecule.
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PMID:Molecular mechanism of action at estrogen receptor alpha of a new clinically relevant antiestrogen (GW7604) related to tamoxifen. 1115 57

Tamoxifen (TAM) is the endocrine treatment of choice in the first-line therapy for all stages of breast cancer, in both pre- and postmenopausal women. Some clinical studies indicated a small but significant increase in the risk of subsequent endometrial carcinoma in breast cancer women who take TAM as an adjuvant therapy. In this study, we present two cases of breast cancer patients in whom endometrial cancer was diagnosed during TAM treatment; the current status of knowledge on the relationship between TAM use and the risk of endometrial cancer is reviewed.
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PMID:Endometrial cancer in patients with breast carcinoma treated with tamoxifen: report of two cases and the literature overview. 1120 46

We critically examined the literature regarding tamoxifen and raloxifene for breast cancer chemoprevention, a controversial topic of interest to all providers of health care services for women. The National Surgical Adjuvant Breast and Bowel Project showed that tamoxifen decreased the incidence of breast cancer in women at increased risk. Two European studies did not confirm this benefit. Although well-tolerated, tamoxifen chemoprevention continues to be associated with an increased risk of endometrial cancer. Raloxifene is a promising agent that has not been established to reduce the incidence of breast cancer in women at increased risk and currently should not be considered an alternative to tamoxifen outside of clinical trials. Tamoxifen results in a decreased risk of causing breast cancer in women at increased risk for having the disease. Women at increased risk are encouraged to participate in the ongoing clinical trial comparing tamoxifen and raloxifene for breast cancer prevention.
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PMID:Chemoprevention of breast cancer. 1121 47

Tamoxifen's agonist effect on the endometrium has been associated with an increased incidence of endometrial carcinoma. It has been suggested that this agonist effect may be averted by the concomitant use of a progestational agent. We report two patients with breast cancer receiving tamoxifen who developed endometrial carcinoma and atypical endometrial hyperplasia, respectively. In one patient, this occurred despite the use of concomitant megestrol acetate. In the other patient, tamoxifen-associated endometrial hyperplasia persisted and progressed despite cessation of tamoxifen and initiation of megestrol acetate therapy. These cases may have implications for strategies to avert tamoxifen induced endometrial neoplasia.
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PMID:Failure of megestrol acetate to reverse tamoxifen induced endometrial neoplasia: two case reports. 1124 Jul 94


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