When it comes to treating breast cancer, hormone therapy is one option that doctors may prescribe. This treatment works by either stopping the production of hormones or blocking the effects of hormones on cancer cells. While hormone therapy can effectively treat breast cancer, there are also some potential risks and side effects associated with this type of treatment. In this article, we will look at some of the pros and cons of hormone therapy for breast cancer.
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What Is Hormone Therapy?
Hormone therapy for cancers works by blocking the hormones from attaching to their receptors on the cancer cells and preventing their growth.
It also decreases the production of specific hormones in the body.
Hormone therapy for breast cancer is effective only if it has receptors for estrogen or progesterone.
They are called ER-positive and PR-positive breast cancer, respectively.
These types of breast cancers rely on hormones for their growth.
Thus, lowering the production or preventing the attachment of hormones can help treat cancer.
Hormone therapy can be done before surgery to shrink the tumor for easy removal.
It can also be done after surgery to reduce the chances of recurrence.
Hormone therapy is available via pills, injections or surgery that removes hormone-producing organs, namely the ovaries in women and the testicles in men.
Types Of Hormone Therapy For Breast Cancer
Treatment That Blocks Estrogen Production: Aromatase Inhibitors
Aromatase inhibitors block the aromatase enzyme activity.
This enzyme helps produce estrogen in the body.
Aromatase inhibitor medications are typically given to postmenopausal women.
Premenopausal women have too much estrogen for aromatase inhibitors to be effective.
In this case, aromatase inhibitors may be used in combination with another drug that can suppress ovarian function.
Examples of aromatase inhibitors approved by the FDA are anastrozole (Arimidex) and letrozole (Femara), both of which temporarily inactivate aromatase, and exemestane (Aromasin), which permanently inactivates aromatase.
Treatment That Suppresses Ovarian Function
Before menopause, ovaries produce the majority of estrogen.
Breast cancer in these women can be treated by suppressing (or eliminating, if required) the ovarian function.
Surgery (removal of ovaries - oophorectomy) and radiation therapy are two options for this.
They both are permanent treatment options.
Ovarian function can also be temporarily suppressed with gonadotropin-releasing hormone (GnRH) agonists, also known as luteinizing hormone-releasing hormone (LHRH) agonists.
These medicines block and interfere with the signals that instruct the ovaries to produce estrogen.
Treatment That Blocks Estrogen’s Effects
ER+ breast cancers depend on estrogen’s attachment to cancer cells for growth.
Several drugs interfere with estrogen binding to stop or slow breast cancer growth.
Some of them are
- Selective estrogen receptor modulators (SERMs): Instead of estrogen, SERMs bind to the estrogen receptors on cancer cells, thereby hindering their growth. Examples of SERMs approved by the FDA for breast cancer treatment are tamoxifen (Nolvadex) and toremifene (Fareston). SERM mimics estrogen activity in other tissues, such as bone or the uterus.
- Fulvestrant: It works in a similar way as SERMs to halt cancer growth. However, fulvestrant doesn’t mimic estrogen.
Pros and Cons of Hormone Therapy for Breast Cancer
Aromatase Inhibitors
Pros
- Effective treatment options for postmenopausal women.
- Decreases the chance of breast cancer recurring by about 7 to 10 %.
Cons
- May not be effective for premenopausal women.
- Common side effects include vaginal dryness, hot flashes, changes in the menstrual cycle, and mood swings.
- Rare side effects include the risk of heart attack, angina, heart failure, hypercholesterolemia, bone loss, and joint pain.
SERMs and Fluvestrant
Pros
- Effective in premenopausal women.
- Lower risk for 5-year recurrence of ductal carcinoma (type of breast cancer).
- Lower risk of cancer developing in the other breast.
- Higher chances of longer survival.
Cons
- Risk of bone pain due to tumor flare.
- SERMs can increase the risk of developing endometrial cancer and uterine sarcoma in postmenopausal women.
- Small risk for deep vein thrombosis.
- Risks for eye problems like cataracts.
Gonadotropin-releasing Hormone (GnRH) Agonists
Pros
- Removal of ovaries can be avoided.
- Effective in premenopausal women.
Cons
- Risk of bone loss.
- May cause mood swings and depression.
- May result in loss of libido.
- Common side effects like hot flashes and night sweats.
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Other Treatment Options for Breast Cancer
Breast cancer treatment depends on a lot of factors like the stage of cancer, the type, how fast the tumor is growing, the tumor’s recurrence rate, and the age, health, and menopausal stage of the woman.
Other than hormone therapy, a few options for breast cancer treatment are:
- Chemotherapy: Uses a drug to shrink or kill cancer cells. The drugs can be in the form of a pill, intravenous drip, or both.
- Immune therapy: Works with the body’s immune system to help it fight and destroy cancer cells or control side effects from other treatments.
- Radiation therapy: Uses high-energy rays (like X-rays) to kill cancer cells.
- Surgery: Operation to cut out the cancer tissue.
Summary: Pros and Cons of Hormone Therapy for Breast Cancer
Hormone therapy works by lowering the levels or blocking the effects of hormones that help cancer cells thrive.
In breast cancer, hormone therapies can block estrogen production or prevent it from binding to the cancer cells.
Common side effects of hormone therapy include hot flashes, changes to the menstrual cycle, mood swings, night sweats, and lowered sexual drive.
Rarely, bone loss, blood clots, heart failure, and cataracts may occur.
Other treatment options for breast cancer include chemotherapy, radiation, immune therapy, and surgery.
References
- https://www.cancer.gov/types/breast/breast-hormone-therapy-fact-sheet
- https://newsnetwork.mayoclinic.org/discussion/consider-both-the-risks-and-benefits-of-taking-medication-to-prevent-cancer-recurrence/
- https://www.ncbi.nlm.nih.gov/books/NBK65969/
- https://www.mayoclinic.org/tests-procedures/hormone-therapy-for-breast-cancer/about/pac-20384943
- https://www.cancer.org/cancer/breast-cancer/risk-and-prevention/deciding-whether-to-use-medicine-to-reduce-breast-cancer-risk.html
