Hormone Therapy For Breast Cancer

“I laughed more in the hospital than I ever have in my life, making fun of all the weird things that were mining to me.” -Christina Applegate, a breast cancer survivor.

To understand hormonal therapy for breast cancer, let us learn the basic insights of hormones and their impact on breast cancer. Hormones function as chemical messengers in your body, directing the actions of cells and tissues at various locations, typically reaching their targets through the bloodstream. Estrogen and progesterone are two hormones produced by ovaries in pre-menopausal women and various tissues in both women and men. They influence female sex characteristics, bone growth, menstrual cycles, and pregnancy. 

However, in the context of breast cancer, these two specific hormones can also fuel certain types of breast cancer by triggering the growth and spread of cancer cells. These are called hormone-sensitive (HR-positive) breast cancers activated through estrogen and progesterone receptors (ERs and PRs) on cancer cells, stimulating gene expression and cell growth. Doctors determine hormone receptor status (ER positive, PR positive) by testing cancer tissue samples. HR-positive breast cancers are often both ER and PR-positive.

Breast cancers without ERs are termed ER-negative. If they lack both ER and PR, they may be called HR-negative. Around 67%–80% of women's breast cancers are ER-positive. In comparison, about 90% of men's breast cancers are ER-positive, and 80% are PR-positive.

Decoding Hormonal Therapy For Breast Cancer

What is hormone therapy for breast cancer? Hormone therapy, also called endocrine therapy, is a specialized treatment designed to slow down or halt the growth of hormone-sensitive breast cancers. This is accomplished by inhibiting the body's ability to manufacture hormones or interfering with hormone effects on breast cancer cells. Note that tumors lacking hormone receptors, referred to as hormone insensitive, do not respond to hormone therapy.

Types Of Hormone Therapy Used In Breast Cancer

1. Drugs that are used to block ovary function:

Blocking ovary function can be done either surgically by removing the ovaries (called oophorectomy) or through hormonal therapy medications like ovarian suppression drugs such as goserelin and leuprolide.

2. Drugs that block estrogen production:

Estrogen production is blocked by using aromatase inhibitors. These drugs halt the activity of the enzyme called aromatase, which the body uses to produce estrogen in the ovaries. Some of the aromatase inhibitors approved by the FDA are anastrozole and letrozole, which temporarily inactivate aromatase, and exemestane, which permanently inactivates aromatase.

3. Drugs that block the effect of estrogen:

The effect of estrogen can be blocked by using drugs that interfere with estrogen's ability to stimulate the growth of breast cancer cells. These are selective estrogen receptor modulators (SERMs) that bind to estrogen receptors, preventing estrogen from binding. An example of SERMs approved by the FDA for treating breast cancer is tamoxifen.

Who Gets Hormone Therapy For Breast Cancer?

When you are diagnosed with breast cancer, your medical team examines whether your cancer cells possess estrogen or progesterone receptors, identifying whether they rely on these hormones for proliferation. If they do, hormone therapy is likely to be recommended as a crucial part of your treatment. If you have previously undergone breast cancer treatment, this therapy can significantly reduce the chances of a recurrence and lower the risk of new cancers forming in your other breast. Furthermore, if you have a family history of the disease or genetic predisposition, your doctor might advise hormone therapy to decrease your likelihood of developing breast cancer.

Moreover, if you are diagnosed directly with hormone-sensitive breast cancer, then your doctor might recommend hormone therapy for you. For early-stage cancer, medications like tamoxifen or aromatase inhibitors are used after surgery, reducing the risk of recurrence. The choice and duration of therapy are tailored to your specific case. In the advanced stage, hormone therapy, often combined with targeted therapies for breast cancer like palbociclib or abemaciclib, can manage cancer that has spread. In some cases, hormone therapy is used before surgery to shrink tumors. Your treatment decisions will be personalized and made in consultation with your healthcare provider.

The Efficacy Of Breast Cancer Hormone Therapy

How effective is breast cancer hormonal therapy? The survival rate in both females and males has significantly reduced over the years.

• The overall 5-year survival rate is 90.3% for all female breast cancer.

• The 5-year survival rate for hormone-sensitive breast cancer in females is slightly higher than in HR-negative cases.

• The 5-year survival rate for male breast cancer is 84.7% (2007–2016).

• Tamoxifen and aromatase inhibitors like anastrozole have significantly reduced cancer deaths.

• Research indicates that taking hormone therapy for less than two years results in lower survival rates.

• Extending the duration of hormone therapy is crucial for increasing survival rates.

Pros And Cons Of Breast Cancer Hormone Therapy

Pros of Hormone Therapy:

1. Reduced risk of recurrence

2. Improved survival rates

3. Tumor shrinkage

4. Prevention in high-risk individuals

5. Combination therapies for enhanced effectiveness

Cons of Hormone Therapy:

1. Side effects

2. Resistance development

3. Not suitable for all breast cancers

4. Interaction with other medications

5. Individual variability

Side Effects Of Hormone Therapy For Breast Cancer

Common Side Effects:

• Hot flashes

• Night sweats

• Vaginal dryness

• Disrupted menstrual cycle

 Serious Side Effects:

• Blood clots

• Stroke

• Cataracts

• Uterus cancer

• Bone loss (Pre-menopausal Women)

• Mood swings,  depression, and loss of libido (sex drive)

• For men:  Headaches, nausea, vomiting, skin rash, impotence, and loss of libido (sex drive).

Darlaine's Breast Cancer Journey 

Are you worried about being diagnosed with HR-positive breast cancer? Here is a story of hope and courage from survivor Darlaine that might inspire you. In 2016, at the age of 55, Darlaine faced invasive lobular breast cancer. Despite facing several challenges, she underwent surgeries and hormonal therapy, found support in online communities, and dedicated herself to a project helping other survivors. Throughout this journey, she unearthed her inner strength, which restored her confidence. You can read her inspiring story [here].

FAQs: Hormonal Therapy Demystified

Q: What is the difference between hormone therapy for breast cancer and menopausal hormone therapy (MHT)?

A: Hormone therapy for breast cancer and menopausal hormone therapy (MHT), also referred to as hormone replacement therapy (HRT), may sound similar, but they serve completely different purposes. Hormone therapy for breast cancer acts as a shield, blocking the growth of HR-positive breast cancer cells. Conversely, MHT can unintentionally stimulate the growth of HR-positive breast cancer.

Q: Can women continue MHT or HRT if diagnosed with HR-positive breast cancer?

A: Unfortunately, no. If someone taking MHT or HRT is diagnosed with HR-positive breast cancer, it is usually advised to stop the therapy. Continuing MHT in such a scenario can unintentionally encourage the growth of cancer cells.

Q: Can hormone therapy be used to prevent breast cancer?

A: Yes. The majority of breast cancers are ER-positive, and clinical trials have been conducted to determine whether hormone therapy can be used to prevent breast cancer in women who are predisposed to the disease. As a result of these trials, the FDA has approved tamoxifen and raloxifene to lower the chance of developing breast cancer in women at high risk of the illness. Tamoxifen is safe to use regardless of menopause. Raloxifene is exclusively approved for postmenopausal women.

The Bottom Line

In summary, hormone therapy marks a significant advancement in breast cancer treatment. Its personalized approach, backed by extensive research, offers hope and improved patient outcomes. Moving forward, continued support for research and accessibility to these treatments are vital. With these efforts, we can empower more individuals, ensuring a brighter and healthier tomorrow for everyone affected by breast cancer.

Disclaimer

This blog is for general awareness purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Hormone therapy for breast cancer is a specialised medical treatment and its suitability, dosage, and duration vary significantly depending on each patient's individual condition, hormone receptor status, and overall health. The information shared here should not be used to self-diagnose or make independent treatment decisions. Always consult a qualified oncologist or breast cancer specialist before starting, changing, or stopping any hormone therapy.