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Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonist/antagonists (ERAAs), are a class of drugs that act on the estrogen receptor (ER). A characteristic that distinguishes these substances from pure ER agonists and antagonists is that their action is different in various tissues, thereby granting the possibility to selectively inhibit or stimulate estrogen-like action in various tissues.
Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. It is also being studied for other types of cancer. It has been used for Albright syndrome. Tamoxifen is typically taken daily by mouth for five years for breast cancer.
Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exogenously. They may also be used for chemoprevention in women at high risk for breast cancer.
Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers.
Toremifene, sold under the brand name Fareston among others, is a medication which is used in the treatment of advanced breast cancer in postmenopausal women. It is taken by mouth.
Virgil Craig Jordan,, is a scientist with American and British citizenship specializing in drugs for breast cancer treatment and prevention. Currently, he is Professor of Breast Medical Oncology, and Professor of Molecular and Cellular Oncology at the University of Texas MD Anderson Cancer Center, Houston, Texas. Previously, he was Scientific Director and Vice Chairman of Oncology at the Lombardi Comprehensive Cancer Center of Georgetown University. Jordan was the first to discover the breast cancer prevention properties of tamoxifen and the scientific principles for adjuvant therapy with antihormones. More recently his work has branched out into the prevention of multiple diseases in women with the discovery of the drug group, selective estrogen receptor modulator (SERMs). Currently, he plans to develop a new Hormone Replacement Therapy (HRT) for post-menopausal women that prevents breast cancer and does not increase the risk of breast cancer.
Hormonal therapy in oncology is hormone therapy for cancer and is one of the major modalities of medical oncology, others being cytotoxic chemotherapy and targeted therapy (biotherapeutics). It involves the manipulation of the endocrine system through exogenous or external administration of specific hormones, particularly steroid hormones, or drugs which inhibit the production or activity of such hormones. Because steroid hormones are powerful drivers of gene expression in certain cancer cells, changing the levels or activity of certain hormones can cause certain cancers to cease growing, or even undergo cell death. Surgical removal of endocrine organs, such as orchiectomy and oophorectomy can also be employed as a form of hormonal therapy.
Breast cancer management takes different approaches depending on physical and biological characteristics of the disease, as well as the age, over-all health and personal preferences of the patient. Treatment types can be classified into local therapy and systemic treatment. Local therapy is most efficacious in early stage breast cancer, while systemic therapy is generally justified in advanced and metastatic disease, or in diseases with specific phenotypes.
Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inhibiting or suppressing estrogen production. Antiestrogens are one of three types of sex hormone antagonists, the others being antiandrogens and antiprogestogens. Antiestrogens are commonly used to stop steroid hormones, estrogen, from binding to the estrogen receptors leading to the decrease of estrogen levels. Decreased levels of estrogen can lead to complications in sexual development. Antiandrogens are sex hormone antagonists which are able to lower the production and the effects that testosterone can have on female bodies.
The estrogen receptor test (ERT) is a laboratory test to determine whether cancer cells have estrogen receptors. This information can guide treatment of the cancer.
Antihormone therapy is a type of hormone therapy that suppresses selected hormones or their effects, in contrast with hormone replacement therapy, which encourages hormone activity.
A hormone-receptor-positive (HR+) tumor is a tumor which consists of cells that express receptors for certain hormones. The term most commonly refers to estrogen receptor positive tumors, but can also include progesterone receptor positive tumors. Estrogen-receptor-positive tumors depend on the presence of estrogen for ongoing proliferation.
Nafoxidine or nafoxidine hydrochloride is a nonsteroidal selective estrogen receptor modulator (SERM) or partial antiestrogen of the triphenylethylene group that was developed for the treatment of advanced breast cancer by Upjohn in the 1970s but was never marketed. It was developed at around the same time as tamoxifen and clomifene, which are also triphenylethylene derivatives. The drug was originally synthesized by the fertility control program at Upjohn as a postcoital contraceptive, but was subsequently repurposed for the treatment of breast cancer. Nafoxidine was assessed in clinical trials in the treatment of breast cancer and was found to be effective. However, it produced side effects including ichthyosis, partial hair loss, and phototoxicity of the skin in almost all patients, and this resulted in the discontinuation of its development.
Kathleen I. Pritchard, is the head of oncology at Sunnybrook Health Sciences Centre in Toronto, Canada, specializing in breast cancer therapies, and leading the clinical trials division of the centre. She has authored numerous studies on women's health, breast cancer, hormone replacement therapy, public health, and research methodology. According to Thomson Reuters, Pritchard was one of the most cited researchers in the world in 2014 and 2015.
Ethamoxytriphetol is a synthetic nonsteroidal antiestrogen that was studied clinically in the late 1950s and early 1960s but was never marketed. MER-25 was first reported in 1958, and was the first antiestrogen to be discovered. It has been described as "essentially devoid of estrogenic activity" and as having "very low estrogenic activity in all species tested". However, some estrogenic effects in the uterus have been observed, so it is not a pure antiestrogen but is, instead, technically a selective estrogen receptor modulator (SERM). For all intents and purposes, it is a nearly pure antiestrogen, however.
Elacestrant, sold under the brand name Orserdu, is an anticancer medication which is used in the treatment of breast cancer. It is taken by mouth.
A hormone-sensitive cancer, or hormone-dependent cancer, is a type of cancer that is dependent on a hormone for growth and/or survival. Examples include breast cancer, which is dependent on estrogens like estradiol, and prostate cancer, which is dependent on androgens like testosterone.
A sex-hormonal agent, also known as a sex-hormone receptor modulator, is a type of hormonal agent which specifically modulates the effects of sex hormones and of their biological targets, the sex hormone receptors. The sex hormones include androgens such as testosterone, estrogens such as estradiol, and progestogens such as progesterone. Sex-hormonal agents may be either steroidal or nonsteroidal in chemical structure and may serve to either enhance, inhibit, or have mixed effects on the function of the sex hormone systems.
Endocrine therapy is a common treatment for estrogen receptor positive breast cancer. However, resistance to this therapy can develop, leading to relapse and progression of disease. This highlights the need for new strategies to combat this resistance.
Breast and ovarian cancer does not necessarily imply that both cancers occur at the same time, but rather that getting one cancer would lead to the development of the other within a few years. Women with a history of breast cancer have a higher chance of developing ovarian cancer, vice versa.
References
- ↑ Kohler BA, Sherman RL, Howlader N, Jemal A, Ryerson AB, Henry KA, Boscoe FP, Cronin KA, Lake A, Noone AM, Henley SJ, Eheman CR, Anderson RN, Penberthy L (June 2015). "Annual Report to the Nation on the Status of Cancer, 1975-2011, Featuring Incidence of Breast Cancer Subtypes by Race/Ethnicity, Poverty, and State". Journal of the National Cancer Institute. 107 (6): djv048. doi:10.1093/jnci/djv048. PMC 4603551 . PMID 25825511.
- 1 2 3 4 "Hormone Therapy for Breast Cancer". National Cancer Institute. 2017-03-03. Retrieved 2018-11-07.
- ↑ Davies C, Godwin J, Gray R, Clarke M, Cutter D, Darby S, McGale P, Pan HC, Taylor C, Wang YC, Dowsett M, Ingle J, Peto R (August 2011). "Relevance of breast cancer hormone receptors and other factors to the efficacy of adjuvant tamoxifen: patient-level meta-analysis of randomised trials". Lancet. 378 (9793): 771–84. doi:10.1016/S0140-6736(11)60993-8. PMC 3163848 . PMID 21802721.