Breast Cancer Hormone Therapy

Breast cancer hormone therapy is a treatment that halts the production of estrogen and progesterone, or interferes in the areas where they act, delaying or interrupting tumor growth. Find out more.
Breast Cancer Hormone Therapy

In some types of breast cancer, hormones such as estrogen and progesterone stimulate the tumor’s growth. These subtypes of cancer are called “luminal” and score positive for estrogen and/or progesterone receptors. 

Treatments to prevent this are called hormone therapy or endocrine therapy. When metastasis occurs, there is a possibility of malignant cell growth almost anywhere in the body, not just breast tissue.

Types of hormone therapy for breast cancer

Certain drugs, such as selective estrogen receptor modulators, are able to prevent hormones regularly produced by the body from bonding to cancerous cells. When this occurs, the tumor’s growth can be delayed and lead to these cells’ death.

As for aromatase inhibitors, they are a drug class that reduces the amount of estrogen in the body, by inhibiting the enzyme that produces the hormone. This way, this drug prevents cancerous cells from accessing the hormone they need to grow and multiply. They are only indicated for women who have already begun menopause. 

Women who haven’t yet entered menopause can receive a treatment that halts the production of hormones in the ovaries. The options are:

  • Surgical removal of the ovaries (oophorectomy)
  • Radiotherapy, and
  • Medication

Women who undergo one or more of these procedures are able to receive treatment with aromatase inhibitors, indicated for post-menopause patients.

Possible adverse reactions and complications

Since hormone therapy blocks the organisms from producing hormones, or interferes with how they act, they can cause some side effects. How these effects appear and how intense they are depend on the hormone therapy in use and how the body responds. 

  • In hormone therapy for breast cancer treatment, the most common side effects observed are:
  • Hot flashes;
  • Vaginal dryness;
  • Alterations in the menstrual cycle (for women that have not yet begun menopause);
  • Decreased libido;
  • Nausea;
  • Mood swings;
  • Difficulty falling asleep;
  • Fatigue;
  • Articular and muscular pain; and
  • Osteopenia or osteoporosis.

Other possible but infrequent adverse reactions include:

  • Presence of clots (thrombi) in veins;
  • Occurrence of endometrial or uterine cancer;
  • Cataract;
  • Stroke; and
  • Cardiovascular disease.
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