The use of Tamoxifen for the treatment of breast cancer

As indicated by Morrow and Gradishar (2002), breast cancer affects women in the ratio of one to eight in their lives that is approximately 12 of all women. It is the second major cause of cancer deaths among women in the world exceeded only by cancer of the lungs. The chance that the death of a woman will result from breast cancer is about 3. Though one cannot clearly tell why some women get breast cancer there are some risk factors associated with its development. Age, genetics and personal factors, such as early adolescence and late menopause, are all linked to breast cancer development. Breast cancer also affects males though not at a high level as compared to women. Breast cancer develops in men who have attained the age of 60 years. It is estimated that around 2,000 new cases of invasive breast cancer are diagnosed in men and that about 450 of them die annually. Breast cancer cases in men comprise about 1 of all cases of breast cancer.

Breast cancers can be treated through various ways. One of them is through drugs.  Tamoxifen is a medication taken through the mouth as a tablet, which works through interference of the activity of estrogen a female hormone that promotes development of breast cancer. This drug has been in use for treatment of breast cancer for both men and women for more than 30 years. It has been used for treating both early-stage and breast cancer that has metastasized.

Tamoxifen is also used as an adjuvant therapy to avoid initial breast cancer from recurring and also help reduce cases of emergence of new cancers in the breast. When used for treatment of metastasized breast cancer, Tamoxifen impedes the growth of cancerous cells that may be present in the body. For the past one decade, Tamoxifen has been used to lower the risk of breast cancer among women. Women with ductal carcinoma in situ (DCIS), a condition that leads to the development of breast cancer are treated using Tamoxifen. The advantages of using Tamoxifen in the treatment of breast cancer outweigh its disadvantages by far. The period through which patients with breast cancer should take Tamoxifen varies from one patient to another. This variation occurs as a result of the cancer cells response to treatment and also other factors.

Estrogen is one of the major factors that promote the development of breast cancer cells. Some breast cancers are referred to as estrogen-receptor positive because they have a biding site for estrogen. Breast cancer cells require estrogen so as to grow. The effect of estrogen on breast cancer cells is greatly impeded by Tamoxifen making it to be referred to as anti-estrogen.  Tamoxifen competitively binds to estrogen receptors on breast cancer cells, thereby developing a nuclear complex that lowers the synthesis of DNA. As a result it hinders the expression of estrogen-regulated genes, which include the growth as well as angiogenic factors produced by the cancer cells that may activate growth by autocrine mechanisms. This leads to a blockage in the G1 phase of the cell cycle thereby slowing down proliferation of the cells. Tamoxifen makes caner cells accumulate in the G0 and G1 stages. Tamoxifen is therefore cytostatic. As a result breast cancer regresses due to altered balance between cell loss and cell proliferation. The drug may also directly bring about programmed cell death. Tamoxifen is effectively absorbed in the mouth. It is then distributed in the body through the blood. High concentrations of the drug are found in the uterus, breast, and the ovary. Its metabolism occurs through the hepatic microsomal oxidation system.

The rate of death due to breast cancer, according to Klinik, et al (1998), has been declining since 1990 due to increased awareness and screening. Chemotherapy is one of the novel techniques used in the treatment of breast cancer. During the last few years hormonal treatment of breast cancer has been revisited. Future research trends are aimed at treating breast cancer based on endocrine perspective.


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