Who Should Use Tamoxifen
Tamoxifen can help women and men with hormone receptor-positive breast cancer. The drug can lower the risk of breast cancer in:
- Women who are high-risk of breast cancer due to a family history of disease or mutated breast cancer genes.
- Women and men who have already been diagnosed with breast cancer to prevent recurrence of cancer, including:
- Development of breast cancer in the opposite, untreated breast.
- American Cancer Society. Breast Cancer Hormone Receptor Status. Accessed 11/18/2021.
- American Cancer Society. Hormone Therapy for Breast Cancer. Accessed 11/18/2021.
- American Cancer Society. Tamoxifen and Raloxifene for Lowering Breast Cancer Risk. Accessed 11/18/2021.
- BreastCancer.org. Low-Dose Tamoxifen May Be an Option to Reduce Risk of Recurrence, Invasive Disease After Non-Invasive Breast Cancer. Accessed 11/18/2021.
- BreastCancer.org. Tamoxifen . Accessed 11/18/2021.
- National Breast Cancer Foundation. Hormone Therapy. Accessed 11/18/2021.
- National Cancer Institute. Hormonal Therapy. Accessed 11/18/2021.
- Susan G. Komen. Side Effects of Tamoxifen. Accessed 11/18/2021.
- Susan G. Komen. Tamoxifen. Accessed 11/18/2021.
- Susan G. Komen. Tamoxifen and Raloxifene to Reduce Breast Cancer Risk. Accessed 11/18/2021.
- Susan G. Komen. Tumor Characteristics: Hormone Receptor Status. Accessed 11/18/2021.
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Hormone Therapy For Breast Cancer
Some types of breast cancer are affected by hormones, like estrogen and progesterone. The breast cancer cells have receptors that attach to estrogen and progesterone, which helps them grow. Treatments that stop these hormones from attaching to these receptors are called hormone or endocrine therapy.
Hormone therapy can reach cancer cells almost anywhere in the body and not just in the breast. It’s recommended for women with tumors that are hormone receptor-positive. It does not help women whose tumors don’t have hormone receptors .
Estrogen Balance For Reduced Breast Cancer Risk
Theres a strong association between estrogen and breast cancer. While there are no guarantees when it comes to cancer, keeping your estrogen balanced through smart lifestyle changes like those Ive listed above can reduce your risk and benefit your overall hormone health.
If you’re looking for a comprehensive approach that can help you achieve optimal hormonal balance, my free Hormone Starter Kit includes a 7 day meal plan, recipes, and other helpful info to get you on the right track.
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What Other Information Should I Know
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body’s response to anastrozole.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
What Are Hormones And Hormone Receptors
Hormones are substances that function as chemical messengers in the body. They affect the actions of cells and tissues at various locations in the body, often reaching their targets through the bloodstream.
The hormones estrogen and progesterone are produced by the ovaries in premenopausal women and by some other tissues, including fat and skin, in both premenopausal and postmenopausal women and in men. Estrogen promotes the development and maintenance of female sex characteristics and the growth of long bones. Progesterone plays a role in the menstrual cycle and pregnancy.
Estrogen and progesterone also promote the growth of some breast cancers, which are called hormone-sensitive breast cancers. Hormone-sensitive breast cancer cells contain proteins called hormone receptors that become activated when hormones bind to them. The activated receptors cause changes in the expression of specific genes, which can stimulate cell growth.
Breast cancers that lack ERs are called ER negative, and if they lack both ER and PR they may be called HR negative.
Approximately 67%80% of breast cancers in women are ER positive . Approximately 90% of breast cancers in men are ER positive and approximately 80% are PR positive .
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What Does Estrogen Do For Your Health
Before diving into its role in breast cancer, lets begin by looking at all the beautiful things estrogen does for us. Aside from all the ways it impacts reproductive health, from your monthly cycle to pregnancy, estrogen plays a positive role in functions like:
- Libido, fertility, and sexual health
- Healthy stress response
- Cognitive function
Turning Off The Ovaries With Medication
The ovaries can be shut down temporarily with medication. This is usually done by giving a course of monthly injections of goserelin . This gradually causes the levels of oestrogen to fall, which leads to temporary menopause.The menstrual periods stop and other symptoms of menopause may develop . These symptoms can be reversed. If the injections are stopped, the oestrogen levels and menstrual periods return to normal. Some women who are considering having their ovaries removed have these injections for a few months to test out the menopausal symptoms. They still have the choice of reversing the effect if the side effects are too intense. The use of goserelin is strictly controlled by the Australian Pharmaceutical Benefits Scheme and may not be available to all women.
Can You Reduce Your Risk Of Breast Cancer Related To Estrogen
The connection between estrogen and breast cancer is clear, so optimal levels are vital. I wish I could tell you exactly what to do to avoid a breast cancer diagnosis altogether, but of course, I cant because it’s an issue that’s too complex to offer that type of advice.
That said, there are things you can do to keep your estrogen in check:
Remember that estrogen helps us feel healthy and sexy. The key is maintaining balance with other hormones. Here are my top lifestyle habits that promote healthy estrogen metabolism.
- Maintain a healthy body weight. Remember that your fat tissue can make estrogen by converting androgens into estrogens. This means that as body fat increases, so does the amount of estrogen produced and circulated throughout your tissues.
Scientists estimatee that your risk for developing breast cancer jumps by 30% after menopause if your BMI is above 30. And being overweight appears to be linked to ER+ breast cancers, likely related to the increased estrogen production. While its much easier said than done to maintain body weight, the number one tip I advise for healthy weight is a healthy fiber intake. Try swapping your mindset from how many calories did I eat today to how much fiber from real, whole vibrant foods did I enjoy today?
- Keep xenoestrogens out of your kitchen. Chemicals like BPA, phthalates, and BHT all mimic estrogen in the body. They sneak into our kitchen via canned goods, plastic containers, and other food storage items.
Why Is This Medication Prescribed
Anastrozole is used with other treatments, such as surgery or radiation, to treat early breast cancer in women who have experienced menopause . This medication is also used in women, who have experienced menopause, as a first treatment of breast cancer that has spread within the breast or to other areas of the body. This medication is also used to treat breast cancer in women whose breast cancer has worsened after taking tamoxifen . Anastrozole is in a class of medications called nonsteroidal aromatase inhibitors. It works by decreasing the amount of estrogen the body makes. This can slow or stop the growth of many types of breast cancer cells that need estrogen to grow.
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Can Other Drugs Interfere With Hormone Therapy
Certain drugs, including several commonly prescribed antidepressants , inhibit an enzyme called CYP2D6. This enzyme plays a critical role in the body’s use of tamoxifen because CYP2D6 metabolizes, or breaks down, tamoxifen into molecules, or metabolites, that are much more active than tamoxifen itself.
The possibility that SSRIs might, by inhibiting CYP2D6, slow the metabolism of tamoxifen and reduce its effectiveness is a concern given that as many as one-fourth of breast cancer patients experience clinical depression and may be treated with SSRIs. In addition, SSRIs are sometimes used to treat hot flashes caused by hormone therapy.
Many experts suggest that patients who are taking antidepressants along with tamoxifen should discuss treatment options with their doctors, such as switching from an SSRI that is a potent inhibitor of CYP2D6, such as paroxetine hydrochloride , to one that is a weaker inhibitor, such as sertraline or citalopram , or to an antidepressant that does not inhibit CYP2D6, such as venlafaxine . Or doctors may suggest that their postmenopausal patients take an aromatase inhibitor instead of tamoxifen.
Other medications that inhibit CYP2D6 include the following:
- quinidine, which is used to treat abnormal heart rhythms
How Are Aromatase Inhibitors Taken
Aromatase inhibitors are pills. You take one pill every day.
Postmenopausal women with hormone receptor-positive breast cancer can:
- Begin hormone therapy with an aromatase inhibitor
- Begin hormone therapy with tamoxifen and then after a few years, switch to an aromatase inhibitor
When an aromatase inhibitor is the only hormone therapy given, its taken for 5-10 years.
When an aromatase inhibitor is taken after tamoxifen, the drugs are taken for a combined total of 5-10 years.
Talk with your health care provider about how long you should take an aromatase inhibitor.
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Hormone Therapy After Surgery For Breast Cancer
After surgery, hormone therapy can be given to reduce the risk of the cancer coming back. Taking an AI, either alone or after tamoxifen, has been shown to work better than taking just tamoxifen for 5 years.
These hormone therapy schedules are known to be helpful for women who are post-menopausal when diagnosed:
- Tamoxifen for 2 to 3 years, followed by an AI for 2 to 3 years
- Tamoxifen for 2 to 3 years, followed by an AI for 5 years
- Tamoxifen for 4Â½ to 6 years, followed by an AI for 5 years
- Tamoxifen for 5 to 10 years
- An AI for 5 to 10 years
- An AI for 2 to 3 years, followed by tamoxifen for 2 to 3 years
- For women who are unable to take an AI, tamoxifen for 5 to 10 years is an option
For most post-menopausal women whose cancers are hormone receptor-positive, most doctors recommend taking an AI at some point during adjuvant therapy. Standard treatment is to take these drugs for about 5 years, or to take in sequence with tamoxifen for 5 to 10 years. For women at a higher risk of recurrence, hormone treatment for longer than 5 years may be recommended. Tamoxifen is an option for some women who cannot take an AI. Taking tamoxifen for 10 years is considered more effective than taking it for 5 years, but you and your doctor will decide the best schedule of treatment for you.
These therapy schedules are known to be helpful forwomen who are pre-menopausal when diagnosedï»¿:
Benefits Of Hormone Therapies In Early And Locally Advanced Breast Cancer Treatment
Treatment with the hormone therapies tamoxifen and/or an aromatase inhibitor lowers the risk of :
- Breast cancer recurrence
- Breast cancer in the opposite breast
- Death from breast cancer
Premenopausal women who get ovarian suppression plus tamoxifen or an aromatase inhibitor may lower these risks more than premenopausal women who get tamoxifen or an aromatase inhibitor alone .
Learn more about tamoxifen.
Aromatase inhibitor plus androgen deprivation therapy
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How Should This Medicine Be Used
Anastrozole comes as a tablet to take by mouth. It is usually taken once a day with or without food. Take anastrozole at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take anastrozole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
You may need to take anastrozole for several years or longer. Continue to take anastrozole even if you feel well. Do not stop taking anastrozole without talking to your doctor.
Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.
If Cancer Has Come Back Or Spread
Hormone therapy can be used to treat breast cancer that has come back or that has spread to another part of the body .
Its given either alone or with other treatments, depending on what treatments you had before.
If your breast cancer came back during or after treatment with hormone therapy, you may be offered a different type of hormone therapy.
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How Hormone Therapy Works
Oestrogen and progesterone are hormones which are naturally produced in the human body. Before menopause, oestrogen is mostly produced by the ovaries. After menopause, when the ovaries are no longer active, a small amount continues to be produced in other tissues such as fat, muscle and adrenal glands.
Normal breast cells contain receptors that are able to recognise these hormones and allow them to access the cells, where they release signals encouraging growth and development. All breast cancers are tested for the presence of these oestrogen and progesterone receptors, using tissue taken at the time of biopsy or surgery. Approximately 70% of breast cancers retain these receptors, and rely on these hormones to grow. These hormone-sensitive cancers are described as oestrogen receptor positive and/or progesterone receptor positive .
Hormone therapy is also used to shrink or slow the growth of a breast cancer when surgery is not appropriate, for example in an older person with other major health issues. It is also used to help shrink advanced stage breast cancers or slow their growth.
Hormone therapy for breast cancer is not the same as HRT . HRT raises the level of oestrogen +/- progesterone in the body and is not used in the treatment of breast cancer.
Estrogen Receptor Blockers Estrogen Receptor Blocker Drugs Attach Directly To And Block The Estrogen Receptors On Cancer Cells So That The Cancer Cells Cant Use Estrogen They Do Not Affect The Level Of Estrogen In The Body Estrogen Receptor Blockers Are Also Called Selective Estrogen Receptor Modulators
Tamoxifen is the most commonly used anti-estrogen drug. It is used in post-menopausal and premenopausal women. Tamoxifen is given by mouth as a pill.
Tamoxifen is the hormonal therapy drug used most often to lower the risk that DCIS or LCIS will lead to an invasive breast cancer.
Tamoxifen very slightly increases the risk for uterine cancer, deep vein thrombosis and stroke. Doctors will carefully weigh these risks against the benefits of giving this drug before they offer it to women who have a personal or a strong family history of these conditions. Usually the benefits of taking tamoxifen outweigh these risks.
Fulvestrant is an anti-estrogen drug that reduces the number of estrogen receptors on breast cancer cells. It is given as an injection into the muscles of the buttocks.
Fulvestrant is used in post-menopausal women if the breast cancer has grown after they were treated with tamoxifen. It is also used in postmenopausal women with locally advanced or metastatic breast cancer that have never been treated with hormonal therapy.
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Is All Breast Cancer Related To Estrogen
Not all breast cancer is linked to estrogen, but estrogen receptor positive cancers are the most common type of breast cancer. And out of ER positive breast cancers, studies also show that around 65% of those cases also respond to progesterone.
Estrogen receptor positive breast cancer means that estrogen encourages the growth of the cancer cells . Part of the treatment plan for these types of cancers usually involves medications that lower estrogen levels in the body or help block the estrogen receptors .
Targeted Therapy For Breast Cancer
A drug can target or change the activity of a specific feature or substance on the cancer cell, leaving normal cells alone. Some targeted therapies for breast cancer include:
- Monoclonal antibodies: Drugs such as trastuzumab and pertuzumab use antibodies made in the laboratory from an immune cell. For women with HER2 positive breast cancer, these antibodies attach to substances on the cancer cell, killing it, blocking its growth, or preventing it from spreading. Monoclonal antibodies can also carry toxins, radioactive substances or other drugs directly to the cancer cells.
- Tyrosine kinase inhibitors: Drugs such as lapatinib block the signals needed for tumors to grow.
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Looking After Your Bones While Taking An Aromatase Inhibitor
Aromatase inhibitors can reduce bone density. This may increase the risk of breaks in the bones. To keep your bones healthy while you are taking this medication, your doctor may recommend that you:
- have a bone density test before and during treatment
- do regular weight-bearing exercise
- maintain a healthy intake of calcium
- ensure a healthy intake of vitamin D
- take other prescription medications to build up your bones if your bone density is already low
If you do show signs of bone thinning or weakening you may need to see your GP or specialist for special treatment for your bones.