Hormone Therapy for Breast Cancer

Overview

Hormone therapy, also called endocrine therapy, is a common option for people with breast cancer that responds to hormones like estrogen or progesterone. Doctors use it only when breast cancer cells have specific hormone receptors.

This treatment helps in two main ways: it blocks hormones from attaching to the cancer cells or reduces how much hormone the body makes. Below are key points about hormone therapy for breast cancer:

Doctors use it after surgery to lower the risk of recurrence.
Sometimes, they give it before surgery to shrink the tumor.
It can control cancer when it has spread to other areas of the body.
Treatments depend on the hormone receptor status of the tumor.

Method	Purpose
Blocks hormone receptors	Stops hormone signals to cancer
Lowers hormone levels	Reduces cancer cell growth signals

Reasons for Hormone Therapy Use

Doctors use hormone therapy in breast cancer treatment when the cancer is hormone-sensitive. This means the tumor grows in response to hormones such as estrogen or progesterone. Cancers include invasive breast cancer, lobular carcinoma, advanced breast cancer, and metastatic breast cancer.

If testing shows that cancer cells have hormone receptors, doctors may recommend hormone therapy. Even if only a small portion of cells test positive, treatment can help lower risks. Healthcare teams use test results to decide if this kind of therapy could benefit the patient. Hormone therapy supports patients in several important ways:

Stops or slows the spread of cancer that depends on hormones.
Reduces the risk that cancer will return after other treatments.
May shrink tumors before surgery.
Can help prevent cancer from forming in other areas.

Possible Negative Effects

Hormone therapy for breast cancer can cause a range of side effects. Common issues include hot flashes, night sweats, and vaginal dryness. Patients also report joint pain, muscle pain, fatigue, and mood changes. Some people experience headaches, bone pain, or nausea. Less frequent but more severe risks include:

Serious Side Effects	Type
Blood clots, pulmonary embolism	Circulatory issues
Stroke	Neurological
Endometrial cancer	Cancer-related
Heart disease	Cardiovascular
Osteoporosis (thinning bones)	Bone health
Cataracts	Vision

These issues depend on the specific hormone therapy used. Some medicines also affect menstrual cycles in premenopausal women or cause impotence in male patients.

What You Can Expect

Some treatments work by stopping hormones from attaching to the cancer cells. These hormones—mainly estrogen and sometimes progesterone—can help breast cancer cells grow. Blocking these hormones may slow or stop the cancer’s growth.

Selective Estrogen Receptor Modulators (SERMs)

This class of medication works by blocking estrogen receptors on breast cancer cells. It is typically taken as a daily pill for 5 to 10 years. These medications are effective for both early and advanced hormone receptor-positive breast cancer and can be used before or after menopause.

One type of SERM is primarily used in people who have already reached menopause. Like others in its class, it is taken once a day and works by preventing estrogen from attaching to tumor cells.

Selective Estrogen Receptor Degraders (SERDs)

This class is administered as an injection, usually every month after a loading period. SERDs are prescribed for individuals after menopause, particularly when the cancer has spread to other parts of the body.

They work by degrading estrogen receptors, stopping the cancer cells from using estrogen to grow. These medications prevent estrogen from linking to its receptor on the tumor cell. Blocking this connection stops the cancer cell from using the hormone to grow.

Drugs That Lower Estrogen Production in the Body

Aromatase inhibitors help by lowering the body’s estrogen levels. Doctors use them only in women who have gone through menopause or in those whose ovaries have been shut down by medicines or surgery. By dropping estrogen amounts, these drugs help stop hormone receptor-positive breast cancer from growing.

Patients take these pills once a day, often for at least five years. In some cases, therapy continues for up to ten years.
In men, doctors may use these medications along with other hormonal drugs to lower hormone levels even more.

Ways to Reduce Ovarian Hormone Production in Younger Women

Premenopausal women may need treatments to turn off or reduce hormone production from their ovaries. This can help make other hormone therapies possible or more effective. Options include:

Medication: Certain injectable medications classified as gonadotropin-releasing hormone (GnRH) agonists temporarily stop the ovaries from making hormones.
Surgery: Surgeons perform an oophorectomy to remove the ovaries so they cannot make estrogen or progesterone at all.
Radiation: Targeted radiation can destroy the hormone-producing ability of the ovaries.

Doctors may use these steps alone or together with other hormone therapies. They are especially useful for women who have not yet gone through menopause naturally or due to other treatments.

Using Targeted Treatments Along with Hormone Medicines

Doctors sometimes combine targeted medicines with hormone therapies. Targeted therapy attacks certain features of cancer cells, like specific proteins, to help hormone therapy work better.

Doctors may prescribe these medicines together with hormone-blocking drugs to help slow cancer growth or keep the cancer from coming back.
Your medical team will help decide if this approach is right for your type of hormone receptor-positive breast cancer.

List of Combined Therapy Benefits

May improve how well hormone therapies work.
Can be considered for advanced or recurring cancer.
Addresses cancers that have become harder to treat through hormone therapy alone.

Doctors usually recommend these combined treatments for those with hormone receptor-positive breast cancer that has not responded to other treatments or has advanced. The specific plan often depends on prior treatments and the exact features of the cancer.

Study Findings

People receiving hormone therapy for breast cancer visit their cancer care team often. The oncologist checks on treatment progress and manages any side effects. Many side effects from hormone therapy can be controlled with changes in medication or supportive care.

Key Points

Hormone therapy after surgery, chemotherapy, or radiation may:
- Lower the chance of cancer returning in those with hormone-sensitive tumors
- Slow or stop the growth of cancer cells in metastatic cases
Testing during therapy helps the care team:
- Track the presence or return of tumor cells
- Decide if the treatment works or needs to be changed

Step	Purpose
Regular check-ups	Monitor treatment effects and side effects.
Lab tests and scans	Detect cancer recurrence or progression.
Care plan adjustment	Improve outcomes based on response.