How Do Hormones Affect Breast Cancer Growth?
Hormones, such as oestrogen and progesterone, are chemicals produced by the body’s glands. Normally, these hormones aid in regulating body cycles such as menstruation. However, these same hormones can sometimes promote cancer growth.
The pathologist will examine the breast cancer cells to see if they have receptors that feed on oestrogen or progesterone, causing them to grow. If your cancer cells have these receptors, your doctor may advise you to take hormone therapy drugs, such as blockers or inhibitors—both types of drugs work by cutting off cancer cells’ supply of hormones.
What Role Do Hormone Blockers Play in Breast Cancer Treatment?
Tamoxifen is the most commonly used hormone therapy medication. It closes the estrogen-shaped openings in the cells, preventing the growth of estrogen-fueled cancers.
Tamoxifen can be taken daily as a pill for up to five years after surgery.
What exactly are hormone inhibitors, and how do they function?
Hormone inhibitors, like hormone blockers, target breast cancer cells with hormone receptors, but they work by reducing the body’s hormone production. When the ‘food supply’ (in this case, oestrogen) to breast cancer cells is cut off, the tumour begins to starve and die.
Combining hormone therapy and chemotherapy outweigh the benefits of either alone. If your tumour has hormone receptors, your doctor may recommend both treatments.
When Should Hormone Blockers Be Used?
The use of hormone inhibitors and blockers may differ depending on a person’s stage of life.
- Hormone blockers are only prescribed to postmenopausal women. They can be given to premenopausal women if the treatment team takes steps to put the ovaries to sleep by preventing them from producing oestrogen or progesterone.
- Hormonal therapy is also known as anti-hormone therapy. Consider it the inverse of hormone replacement therapy (HRT). Suppose pathology tests show that your breast tumour has hormone receptors (referred to in the pathology report as Estrogen receptor positive and progesterone receptor positive). In that case, hormonal therapy may be recommended after your acute treatment (surgery, chemo, and radiation). (See Breast Tissue Pathology Tests.)
- Hormonal therapy prevents breast cancer cells from receiving or using the natural female hormones (oestrogen and progesterone) found in your body, which they require to grow. Hormonal therapy also prevents healthy breast cells from receiving hormones that could stimulate breast cancer cells to regrow, resulting in breast cancer recurrence within the breast or elsewhere in the body.
Options Before Menopause
If you have not yet experienced menopause, your options include the following:
- Tamoxifen: This medication can help prevent the recurrence of the original breast cancer and the development of new cancers in the other breast or elsewhere in your body in the future. It comes in pill form and must be taken daily for at least five years.
- Tamoxifen’s side effects are similar to some menopausal symptoms in general. Hot flashes and vaginal discharge are the most common. Other symptoms include irregular menstrual cycles, bone thinning, headaches, fatigue, nausea, vomiting, vaginal dryness or itching, irritation of the skin around the vagina, and skin rash. Blood clots, strokes, uterine cancer, and cataracts are among the serious side effects.
- LH-RH agonists: These medications prevent the ovaries from producing oestrogen. The oestrogen level gradually decreases. Leuprolide and goserelin are two examples. This medication can be administered via injection under the skin in the stomach area. Hot flashes, headaches, weight gain, thinning bones, and bone pain are all possible side effects. This is known as chemical menopause. This allows the patient to take hormone inhibitor drugs more commonly prescribed to postmenopausal women.
- Surgery to remove your ovaries: Your ovaries are your body’s main source of oestrogen until menopause. When your ovaries are removed, this source of oestrogen is also removed. (A woman who has gone through menopause would not benefit from this type of surgery because her ovaries produce little to no oestrogen.) Menopause occurs immediately after the ovaries are removed. This is known as surgical menopause, and it allows the patient to take hormone-inhibiting medications. The side effects are frequently more severe than those associated with natural menopause but fade over time. Your oncology team can advise you on how to deal with these side effects.
It is important to note that if a patient receives LH-RH agonist treatment or has her ovaries surgically removed, she will most likely be put on an aromatase inhibitor rather than Tamoxifen, but both options remain.
Options Following Menopause
If you have gone through menopause, you have the following options:
- Aromatase inhibitors prevent the body from producing oestrogen (estradiol). Anastrazole, exemestane, and letrozole are a few examples. Hot flashes, nausea, vomiting, and painful bones or joints are all common side effects. Thinning bones and an increase in cholesterol are two serious side effects. This is also a daily pill.
- Tamoxifen: Hormone therapy is administered for at least five years. Tamoxifen is given to women who have gone through menopause for 2 to 5 years. If Tamoxifen is used for less than five years, an aromatase inhibitor is frequently used to complete the five years. Some women have been receiving hormone therapy for more than five years.
More research is being conducted to determine whether taking hormonal therapy for more than five years is beneficial. Some research studies have shown that switching from one hormonal therapy agent to another over five years may be beneficial. Based on your breast cancer pathology and age, your oncologist will discuss the best hormonal therapy regimen for you. It is critical to take these pills daily because you may not reap the benefits of these drugs if you do not adhere to the daily schedule and dosage as prescribed. Overall, hormonal therapy has been shown to reduce the risk of recurrence by 50%.
These medications can be costly. If you require financial assistance in paying for these medications, contact a medical oncology nurse practitioner or social worker for information on obtaining the prescription at a reduced price.
Sexual dysfunction is possible based on the side effects listed above. Make your oncologist aware if you are experiencing decreased libido or vaginal dryness resulting in pain during intercourse, as there may be some options for reducing these side effects.
