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How Hormone Therapy Works in Stage 4 Breast Cancer

Breast Cancer and Hormones

When you hear the term “hormone therapy,” you might think of increasing hormones in a person’s body in order to treat their disease. But for breast cancer treatment, this isn’t the case. In some people with breast cancer, certain hormones actually increase the risk and spread of breast cancer cells.

Instead, hormone therapy is used in breast cancer to slow down tumor growth in cells that are sensitive to hormones. This treatment method won’t work for all tumors, but it may be an option to consider with stage 4 breast cancer.

Role of Estrogen and Progesterone in Breast Cancer

There are many different varieties of breast cancer tumor cells. Tumors that respond to hormones are called “hormone-sensitive.” Hormone-sensitive cancer cells have receptors that receive and respond to hormones. These hormones fuel the tumor’s growth. As the cancer progresses, the tumors may form in other areas of the body too.

Your body produces many types of hormones that control body functions, such as reproduction. Estrogen and progesterone — both female hormones — can contribute to the growth of tumor cells that are particularly sensitive to these hormones.

According to the National Cancer Institute, 70 percent of breast cancer patients have estrogen receptor-positive (ER-positive) cancer. Breast cancer that responds to progesterone is called progesterone receptor-positive (PR-positive). In some cases, a patient might be both ER- and PR-positive.

Blocking Female Hormones

The goal of hormone therapy in breast cancer is to reduce progesterone and/or estrogen levels in the body. This type of therapy only works if the cancer tumors are considered hormone-sensitive. Treatment consists of either blocking the ovaries from producing hormones or binding with hormones or their receptors to minimize their impact.

Hormone therapy is common in stage 1 and stage 2 breast cancers, where a wide range of options may be available. There are only certain hormone therapies available for use in stage 4. They include:

  • anastrozole
  • exemestane
  • fulvestrant
  • letrozole
  • tamoxifen
  • toremifene

Most of these drugs are exclusively used in postmenopausal women, with the exception of tamoxifen and toremifene. These two are used in both men and women of all reproductive stages.

When Hormone Therapy Is Used for Stage 4

Stage 4 breast cancer is difficult to treat because the tumors are no longer exclusive to the breast area and lymph nodes. In this stage, breast cancer has most likely metastasized (spread) to other organs, such as the bones or lungs. It can also spread to the brain or the eyes.

Hormone therapy is considered a systemic treatment most commonly used in earlier stages of breast cancer if hormone-sensitive tumors are detected. The goal of hormone therapy is to improve your symptoms while possibly shrinking the tumors.

Side Effects and Considerations

Due to the nature of this breast cancer treatment, you may experience a decrease in circulating hormones. It’s not uncommon for women to experience:

  • hot flashes
  • mood swings
  • night sweats
  • missed periods
  • vaginal dryness

Men undergoing hormone therapy for breast cancer might experience:

  • nausea or vomiting
  • severe headaches
  • lack of libido or impotence
  • skin rashes

Severe side effects of hormone therapy are rare. Some of the risks include:

  • blood clots
  • stroke
  • heart attacks
  • joint pain
  • bone loss

Hormone therapy also poses the risk of drug interactions. Tamoxifen carries the greatest risk. Talk to your doctor if you’re currently taking:

  • antidepressants
  • antihistamines (such as diphenhydramine) for allergies
  • cimetidine for acid reflux
  • quinidine for heart arrhythmias

Hope Through Hormone Therapy

Stage 4 is the most advanced, and most serious, stage of breast cancer. At this point, it’s understandable to try out all of the options available to treat the cancer.

Hormone therapy can offer the hope of a longer life to the right candidates. Remember that this treatment only works for certain patients who have hormone-sensitive tumors. Although hormone therapy can help increase longevity in stage 4 breast cancer patients, it’s not likely to completely cure the tumors.

Some patients experience recurring breast cancer after going through hormone therapy. In some cases, the cancer may have even advanced a stage. Rather than going through the same treatment, your oncologist will likely switch you to another hormone therapy.

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