How Does Hormone Therapy For Breast Cancer Work
Hormones control nearly all of our bodily functions, from growth and development to emotions, sexual function and even sleep. But hormones, which occur naturally in our bodies, can also fuel the growth of certain breast cancers. We talked with breast medical oncologist Rachel Layman, M.D., to learn about hormone therapy for breast cancer, which can stop or slow the cancer-fueling action of hormones.
What is hormone therapy for breast cancer?
Hormone therapy is a form of treatment that deprives breast cancer of estrogen and progesterone, the two main female hormones that it needs to survive and grow.
Estrogen and progesterone are carried along in the bloodstream. When they encounter a breast cancer cell, they stick to proteins called hormone receptors on the cells surface. This connection acts as an on switch and triggers the cancer cell to grow. The goal of hormone therapy is to prevent hormones from attaching to cancer cells, which deprives the cancer cells of the fuel they need to grow.
Are all breast cancers fueled by hormones?
No, but most are. About 70% of all breast cancers depend on estrogen or progesterone for growth.
How do hormone therapies for breast cancer work?
Hormone therapies reduce or eliminate contact between hormones and breast cancer cells in several different ways:
How and when are hormone therapy medications delivered?
Most hormone therapy drugs are taken as a daily oral pill, though a few are given as injections in the clinic.
Hormones And Breast Cancer
The hormones estrogen and progesterone make some breast cancers grow. They are called hormone-sensitive breast cancers. Most breast cancers are sensitive to hormones.
Estrogen and progesterone are produced in the ovaries and other tissues such as fat and skin. After menopause, the ovaries stop producing these hormones. But the body continues to make a small amount.
Hormone therapy only works on hormone-sensitive cancers. To see if hormone therapy may work, doctors test a sample of the tumor that has been removed during surgery to see if the cancer might be sensitive to hormones.
Hormone therapy can work in two ways:
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
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Can Goserelin Preserve Fertility During Chemotherapy
Chemotherapy can cause damage to the ovaries, reducing the number and quality of eggs and affecting a womans ability to become pregnant. Some studies have shown that goserelin may protect the ovaries during chemotherapy as it temporarily shuts them down . However, the effectiveness of goserelin as a method of preserving fertility is still debated and further research is needed.
Goserelin cannot replace other fertility preservation methods like egg and embryo freezing and even if your periods do return after treatment, this doesnt necessarily mean you have preserved your fertility.
If you want to try to preserve fertility during chemotherapy discuss this with your treatment team before starting treatment.
Goserelin is not suitable during pregnancy or while breastfeeding.
Will The Nhs Fund An Unlicensed Medicine
It’s possible for your doctor to prescribe a medicine outside the uses it’s licensed for if they’re willing to take personal responsibility for this ‘off-licence’ use of treatment.
Your local integrated care board may need to be involved, as it would have to decide whether to support your doctor’s decision and pay for the medicine from NHS budgets.
Page last reviewed: 28 October 2019 Next review due: 28 October 2022
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Hormone Therapy Available At Willamette Valley Cancer Institute
Some cancers grow because of hormones present in the body. Usually, there is too much of a hormone that is fueling the cancers growth. A cancer treatment that slows or stops the growth of cancers that use hormones to grow is called hormone therapy. Prostate and breast cancers are commonly treated with hormone therapies.
Hormone therapy, also called hormonal therapy or endocrine therapy, is commonly used in addition to other cancer treatments. The types of treatment you are prescribed are based on the type of cancer, if it has spread, and how far, if it uses hormones to grow, and if you have other health problems.
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Summary Of Treatment Options For Metastatic Breast Cancer
Hormone receptor-positive, HER2-negative breast cancer
Hormonal therapy is considered the standard initial treatment for HER2-negative metastatic breast cancer that is also hormone receptor-positive. It is often given in combination with targeted therapy. However, chemotherapy may also be given. A clinical trial may also be an option for treatment at any stage.
Hormone receptor-negative, HER2-negative breast cancer
In general, chemotherapy or targeted therapy is given for treatment of triple-negative breast cancer. A clinical trial may also be an option for treatment at any stage.
HER2-positive breast cancer that has spread to parts of the body other than the brain
In general, HER2-targeted therapy is regularly added to treatment for HER2-positive breast cancer that has spread. The drugs used depend on the treatments already given and whether the cancer is hormone receptor-positive. The treatment recommendations for first-line, second-line, and third-line or higher treatment are described below. A clinical trial may also be an option for treatment at any stage.
First-line treatment
Second-line treatment
-
For people with advanced breast cancer that has grown during or after first-line treatment with a HER2-targeted therapy, ASCO recommends trastuzumab deruxtecan as a second-line treatment.
Third-line or higher treatment
HER2-positive breast cancer that has spread to the brain
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Will Taking Goserelin Affect My Periods
During early treatment with goserelin some women may have some vaginal bleeding. If your periods continue, tell your treatment team as your ovaries may not be suppressed.
Within three weeks of the first injection, your oestrogen will be lowered to a level similar to that of a post-menopausal woman and your periods will normally stop. This effect is temporary and will only last for as long as youre having goserelin.
When you stop having goserelin, your ovaries will usually start to produce oestrogen again. Most womens periods will start again within three to twelve months after finishing treatment. However, if youre approaching the age of natural menopause, your ovaries may not start working again.
If youre concerned about going through an early menopause or would like to have children, you can discuss with your treatment team how long to continue goserelin.
If Cancer Comes Back Or Has Spread
AIs, tamoxifen, and fulvestrant can be used to treat more advanced hormone-positive breast cancers, especially in post-menopausal women. They are often continued for as long as they are helpful. Pre-menopausal women might be offered tamoxifen alone or an AI in combination with an LHRH agonist for advanced disease.
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Hormone Therapies For Prostate Cancer Treatment
Male hormones cause prostate cancer cells to grow. Androgens support a healthy prostate gland however, they can also promote the growth of cancerous prostate cells.
When using hormone therapy for prostate cancer, the treatment can block the production or use of androgens in one of the following ways:
What Cyclical Changes Happen To The Breasts During The Menstrual Cycle
Each month, women go through changes in the hormones that make up the normal menstrual cycle. The hormone estrogen is produced by the ovaries in the first half of the menstrual cycle. It stimulates the growth of milk ducts in the breasts. The increasing level of estrogen leads to ovulation halfway through the cycle. Next, the hormone progesterone takes over in the second half of the cycle. It stimulates the formation of the milk glands. These hormones are believed to be responsible for the cyclical changes that many women feel in their breasts just before menstruation. These include swelling, pain, and soreness.
During menstruation, many women also have changes in breast texture. Their breasts may feel very lumpy. This is because the glands in the breast are enlarging to get ready for a possible pregnancy. If pregnancy does not happen, the breasts go back to normal size. Once menstruation starts, the cycle begins again.
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How Do Hormone Therapies Work
Hormone therapy drugs slow or stop the growth of hormone receptor-positive breast cancers in a couple of ways:
- Some hormone therapies, such as tamoxifen, attach to the hormone receptor in the cancer cell and block estrogen from attaching to the receptor.
- Others, such as aromatase inhibitors and ovarian suppression, lower the level of estrogen in the body so the cancer cells cant get the estrogen they need to grow.
Hormonal Therapy For Endometrial Cancer
Cancer of the uterus or its lining, the endometrium, may respond to hormone therapy with progestins. Other types of hormone therapy for endometrial cancer include:
- Aromatase inhibitors
When and why theyre used: Hormone therapy is typically reserved for advanced uterine or endometrial cancer, or for cancer that has returned after treatment. Its often combined with chemotherapy.
Risks: Side effects are similar to those seen with hormone treatment for other types of cancer.
Expert cancer care
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Ovarian Ablation Or Suppression
For women who havent gone through menopause, ovarian ablation may be an option. This can be done medically or surgically. Either method stops estrogen production, which can help inhibit the growth of cancer.
Surgical ablation is done by removing the ovaries. Without production of estrogen from the ovaries, you will enter permanent menopause.
Symptoms of menopause may include:
- vaginal dryness
- changes in sex drive
Serious complications after surgical ablation are rare, but you may be more prone to complications if you have diabetes or obesity, or smoke cigarettes.
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 4½ 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 diagnosed:
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How Is Hormone Therapy Used To Treat Breast Cancer
There are three main ways that hormone therapy is used to treat hormone-sensitive breast cancer:
Adjuvant therapy for early-stage breast cancer:Tamoxifen is FDA approved for adjuvant hormone treatment of premenopausal and postmenopausal women with ER-positive early-stage breast cancer, and the aromatase inhibitorsanastrozole, letrozole, and exemestane are approved for this use in postmenopausal women.
Research has shown that women who receive at least 5 years of adjuvant therapy with tamoxifen after having surgery for early-stage ER-positive breast cancer have reduced risks of breast cancer recurrence, including a new breast cancer in the other breast, and reduced risk of death at 15 years .
Until recently, most women who received adjuvant hormone therapy to reduce the chance of a breast cancer recurrence took tamoxifen every day for 5 years. However, with the introduction of newer hormone therapies , some of which have been compared with tamoxifen in clinical trials, additional approaches to hormone therapy have become common .
Some premenopausal women with early-stage ER-positive breast cancer may have ovarian suppression plus an aromatase inhibitor, which was found to have higher rates of freedom from recurrence than ovarian suppression plus tamoxifen or tamoxifen alone .
Men with early-stage ER-positive breast cancer who receive adjuvant therapy are usually treated first with tamoxifen. Those treated with an aromatase inhibitor usually also take a GnRH agonist.
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 .
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How To Treat Hormone Sensitive Breast Cancer
Several strategies are used to treat hormone-sensitive breast cancer: Blocking ovarian function: Because the ovaries are the main source of estrogen in premenopausal women, estrogen levels in these women can be reduced by eliminating or suppressing ovarian function. Blocking ovarian function is called ovarian ablation.
What The Researchers Did
Dr. Crawfords team reviewed clinical data from nearly 23,000 men who were given ADT injections between 2007 and 2016. Each mans treatment varied by how their ADT was formulated. Some types of ADT are given once a month, and others are given at three-, four-, or six-month intervals. The researchers wanted to know how many men were late on their ADT treatments, and how that would affect the amounts of testosterone in their blood.
During this research, the investigators defined month in two ways: either as one lasting 28 days, which is how months were defined during the clinical trials that set dosing schedules for ADT, or as a calendar month lasting 31 days. ADT was deemed late if it was given after day 28 by the first definition or after day 32 by the second definition.
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Hormone Therapies For Breast Cancer Treatment
Several treatment options are available for treating hormone-sensitive breast cancers. Some drugs block the effects of estrogen on the cancer cells in the breast, while others prevent estrogen production altogether.
Common hormone therapy drugs include Tamoxifen , Arimidex® , and Femara® , along with Faslodex® for recurrent breast cancer.
Breast cancer in males may also be treated with tamoxifen. Tamoxifen is currently being studied as hormone therapy for the treatment of other types of cancer.
Surgery To Stop The Ovaries From Working
This is also a type of ovarian ablation. You might choose to have an operation to remove your ovaries instead of having drug treatment to stop them working. You have this operation as keyhole surgery. It is called laparoscopic oophorectomy and you have it under general anaesthetic . You usually stay in hospital overnight.
The surgeon makes a number of small cuts into your tummy . They put a long bendy tube called a laparoscope into one of the cuts. The laparoscope connects to a video screen.
The surgeon puts small instruments through the other cuts to carry out the operation and remove the ovaries. They close the cuts with stitches and cover them with small dressings.
Removing your ovaries causes you to have a sudden menopause. The symptoms include hot flushes, sweating and mood swings.
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What Are The Side Effects Of Hormone Therapy For Prostate Cancer
Because androgens affect many other organs besides the prostate, ADT can have a wide range of side effects , including:
- loss of interest in sex
Studer UE, Whelan P, Albrecht W, et al. Immediate or deferred androgen deprivation for patients with prostate cancer not suitable for local treatment with curative intent: European Organisation for Research and Treatment of Cancer Trial 30891. Journal of Clinical Oncology 2006 24:18681876.
Zelefsky MJ, Eastham JA, Sartor AO. Castration-Resistant Prostate Cancer. In: Vincent T. DeVita J, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology, 9e. Philadelphia, PA: Lippincott Williams & Wilkins 2011.
Smith MR, Saad F, Chowdhury S, et al. Apalutamide and overall survival in prostate cancer. European Urology 2021 79:150158.