A number of cells in the female body contain receptors for estrogen and estrogen-like substances. Examples of such organs are the breast, uterus, vagina, skin, ovaries and brain. Estrogen binds to receptors on breast cells and stimulates them to divide and replicate. This mechanism, with tamoxifen on the opposite side, turned to measure the estrogen receptors on the cell surface. Breast cancer cells contain estrogen receptors,Tamoxifen sends these cells into a cycle of programmed cell death called apoptosis.
Tamoxifen is an oral as well as other hormones administered. In addition to making the cancer cells to apoptosis, it also acts like estrogen in other tissues and has a positive effect on bone metabolism. compared with tamoxifen estrogen stimulates the uterine lining more and both compounds bind calcium effect of bone.
Several studies have shown thatTamoxifen increases the cure rate in women with invasive breast cancer is still controversial in clinical application. The dispute is a recent clinical study, the women, to determine whether tamoxifen was effective for primary prevention of breast cancer in asymptomatic patients at high risk. At the end of the study with tamoxifen and test a large amount of negative news has exaggerated its potential adverse effects for asymptomatic women treated.There is no doubt that tamoxifen is a highly potent drug for the treatment of patients with breast cancer. Based on the results of another study that the use of tamoxifen, duration of treatment plays an important role in the outcome of drug treatment . This clinical trial compared five years to ten years compared with tamoxifen after the diagnosis of breast cancer. The study showed that five years of tamoxifen significantlyreduce the systemic recurrence of breast cancer. On the other hand, has only another five years and cost the potential risk of uterine cancer with no additional benefit in cure rate. Not all breast cancers, but respond to treatment with tamoxifen. The response rate to tamoxifen varies depending on the abundance of estrogen and progesterone receptors in primary tumor.
Because breast cancer are heterogeneous, it is not in developmentthe same way. About 60 percent of breast cancers contain receptors for estrogen and progesterone, while others contain less. Tamoxifen appears to be more effective in women who have more of these hormone receptors in their tumors than those who do not. On the other hand, in a breast cancer cells have hormone receptors can do more than others. Therefore, the effect of tamoxifen in these changed conditions. It 'also possible that over time breast cancer cells that can develop hormone receptor-positive can not and must not contain more hormone receptors. This may explain why women receiving combination therapy with tamoxifen and chemotherapy, a better response to therapy and treatment have either given alone. In most cases, when chemotherapy and tamoxifen cancer patients are given in a sequence, where they are, first, the chemotherapy is given, hormone receptor negative destroy> Breast cancer cells and then followed by tamoxifen, hormone receptor-positive cells can then act on, the drug may be less sensitive to chemotherapeutic agents.
In some cases seem to perimenopausal women have a difficulty to use with tamoxifen. Most premenopausal women in their 30s and 40s, almost no adverse effects of tamoxifen and older women who have no problem with some hormone replacement therapy 'treatment with tamoxifen.
The main side effect of Tamoxifen is uterine toxicity. Some women, drugs have endometrial thickening, a stimulation of the glands of the uterus, cancer cells are, when it has not gone unnoticed. The possibility of developing cancer of the uterus due to tamoxifen use is quite small, only about one percent. However, the uterus is carefully with ultrasound or a biopsy of the endometrium, monitoring the patient during the annual gynecological exam, if this> Drugs.
Tamoxifen has been developed the first selective modulator of estrogen receptor and is used by more than 20 years. Recently, other drugs in this class have been issued and several more are currently under development. The goal is to develop the drug uterus "perfect" in this class of breast, which prevents cancer without stimulation is beneficial to the skeletal system and is good for the metabolism of fat with minimal side effects as possible.The perfect selective estrogen receptor modulator was also an excellent agent hormone replacement for women, menopause.
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