Breast cancer is a broad category that encompasses several different types of the disease. One specific type is hormone receptor-positive (HR+) breast cancer. When breast cancer is hormone-receptor-positive, the hormones estrogen, progesterone, or both, attach to the cancer cells, causing them to grow faster. 

Hormone therapy blocks the hormones from attaching to the receptors, slowing the growth of cancer cells. While hormone-blocking therapy can be an effective method for treating this type of breast cancer, there are also some considerations about how it might affect your quality of life. Let’s look at how it works, who can use it, and the pros and cons of using this type of cancer treatment.

How Hormone Therapy Works for Breast Cancer

Breast cancers that have receptors for estrogen are called ER-positive (ER+). If progesterone receptors are found on the cancer cells, the breast cancer is PR-positive (PR+). Hormone therapy is effective when the cancer cells are ER+, PR+, or both.

Learn more in our blog: How the Type of Breast Cancer Affects the Treatments You Receive.

These drugs block the hormones from attaching to their receptors on the cancer cells, which prevents growth. Additionally, some hormone therapies reduce the production of a specific hormone in the body. 

When is Hormone Therapy Given?

Hormone therapy can be included at various times during your breast cancer treatment, including:

• Before surgery to shrink the tumor for easy removal (called neoadjuvant therapy).
• After surgery, as part of a complete treatment plan (known as adjuvant therapy).
• To treat cancer that has recurred after treatment or spread to other parts of the body.
• To help reduce the risk of developing cancer in the same breast or in the other breast. 

Sometimes, doctors may also recommend hormone therapy for healthy women who have a family history of breast cancer or genetic mutations, such as BRCA1 and BRCA2, which increase their risk for the disease.

Types of Hormone Therapies for Breast Cancer

There are several approaches to breaking the connection between hormones and breast cancer cells. Here are the three most common categories of hormone therapy for breast cancer.

• Blocking the effect of estrogen on breast cancer cells. When the hormones are unable to access cancer cells, tumor growth slows, and the cancer cells may die. Medications that block hormones fall into two groups: selective estrogen receptor modulators (SERMs), such as Tamoxifen and Toremifene (Fareston), and selective estrogen receptor degraders (SERDs) such as Fulvestrant (Faslodex) and Elacestrant (Orserdu).
• Suppressing ovarian function in premenopausal women. For women who have not yet reached menopause, ovarian ablation can be performed to reduce or eliminate estrogen production. This can be done with surgery to remove the ovaries (oophorectomy) or by using drugs called luteinizing hormone-releasing hormone (LHRH) agonists. Common LHRH drugs include goserelin (Zoladex) and leuprolide (Lupron). These may be used alone or in combination with other hormone therapies.
• Lowering hormone production in women who have gone through menopause. After menopause, your ovaries do not produce estrogen, but body fat can produce estrogen through an enzyme called aromatase. Aromatase inhibitors (AIs) are drugs that reduce the level of post-menopausal estrogen, starving the cancer cells of the fuel they need. Examples of AIs include Letrozole (Femara), Anastrozole (Arimidex), and Exemestane (Aromasin).

Who is a Candidate for Hormone Therapy?

The primary indication for using hormone therapy is the presence of hormone-receptor-positive breast cancer. Your pre- or post-menopausal status will affect the specific set of therapies used.

If you are pre-menopausal, hormone therapy can be used to suppress the ovary’s ability to make estrogen as well as block hormones from attaching to the cancer cells. The specific hormone therapy treatments will be selected specifically for a pre-menopausal woman to avoid causing too much bone thinning or other unwanted side effects. Ovarian suppression, whether surgical or through medication, will essentially cause menopause. Your oncologist may also recommend taking hormone suppression therapy after treatment for up to 10 years to reduce the likelihood of recurrence. 

Compared to pre-menopausal women, there is less need for ovarian suppression, although blocking estrogen made in the fat cells is necessary. Some of the side effects may be more severe in post-menopausal women, but it’s not guaranteed that you will experience them. 

Breast Cancer Hormone Therapy: Pros vs Cons

There are side effects of hormone therapy. For most women, the pros outweigh the cons, making it worthwhile to use. However, the more information you have, the better prepared you'll be to make the best decision for yourself and to prepare for side effects. 

Pros of Hormone Therapy for Breast Cancer

• Improved survival rates. Hormone therapy has been shown to provide long-term treatment benefits over several years.
• Reduces the risk of recurrence. Hormone therapy is one of the most effective methods for preventing hormone-receptor-positive breast cancer from returning, reducing the likelihood of recurrence by at least 40% when used as prescribed.
• It is usually administered orally. Being able to take hormone therapy medications in a pill form at home is much more convenient than receiving infusion treatments.  
• Non-cytotoxic. Unlike chemotherapy, which can kill or damage cells, hormone therapy uses hormones to treat hormone-sensitive breast cancer without the same harmful effects.
• Effective for metastatic cancer. This treatment can help control cancer growth and symptoms in advanced hormone receptor-positive breast cancers.

Cons of Hormone Therapy for Breast Cancer

• Long-term use is required. The duration of hormone therapy varies among patients, but it can last anywhere from 5 to 10 years or longer, depending on individual circumstances.
• Side effects. Because many women use hormone therapies for 5-10 years, this means that side effects can last that long, or longer. Common issues include hot flashes, mood swings, joint pain, vaginal dryness, and fatigue, all of which can affect your quality of life. Talk to your oncologist if you’re having difficulty managing the side effects. They may be able to use a different drug or alter your dose.
  
  Learn more about the side effects of breast cancer hormone therapy. 

• Risk of serious complications. Some patients may experience severe side effects, including blood clots and stroke (especially with Tamoxifen) in post-menopausal women.
• Bone density loss. For pre-menopausal women, bone density is reduced when taking Tamoxifen. 
• Not effective for all breast cancers. Only certain subtypes are effectively treated with hormone therapy. Hormone receptor-negative cancers do not benefit from this type of treatment.  

Hormone Therapy for Breast Cancer at Rocky Mountain Breast Specialists

Each person's breast cancer is unique, and so is their experience with hormone therapy. With over 30 years of experience in delivering world-class cancer care to patients across Colorado, our breast cancer oncologists and surgeons are dedicated to helping you understand your diagnosis. We want you to have the information you need to make these important decisions about your cancer care team and the treatments included in your personalized plan. We are a dedicated, passionate team for our patients, and you are always at the center.

Request an appointment at one of our breast cancer centers throughout Colorado.