What to Expect After Taking Hormone Therapy Drugs for Breast Cancer

Hormone therapy with drug treatment can cause many side effects. These side effects depend on what kind of drug you’re given.

Potential Common Side Effects

Here are some of more common ones.

• Hot flashes

• Weight changes

• Vaginal discharge or irritation

• Nausea

• Irregular periods

Serious, But Rare Side Effects to Discuss With Your Doctor

Here’s a list of the more serious, but rare, side effects. In the long term, aromatase inhibitors are less likely to cause endometrial cancer or blood clots than tamoxifen. However, aromatase inhibitors increase the risk for bone thinning, which can develop from a lack of estrogen. This can make bones more brittle and likely to break. Talk with your doctor about what you can do to prevent or manage these problems, such as exercising and taking calcium. Drugs called bisphosphonates can prevent or reverse bone loss.   Talk with your doctor about whether you need them.

Signs of Endometrial Cancer

Most side effects of hormone therapy are not life-threatening. In very rare cases (less than or equal to 1%), tamoxifen can raise a woman's chance of getting endometrial cancer. That cancer occurs in the lining of the uterus, called the endometrium. If you are taking tamoxifen, get a pelvic exam each year to check for signs of cancer. Also, tell your doctor or nurse bout any of these problems.

• Unusual vaginal discharge

• Vaginal bleeding

• Menstrual irregularities

• Pain or pressure in your lower abdomen

Signs of Blood Clots

Some hormone therapies, such as tamoxifen, carry a slight risk (about 1% over 5 years) of blood clots forming in the deep blood vessels of the legs and groin. Clots can break off and spread to the lungs. Blood clots stop the flow of blood and can cause serious medical problems. Let your doctor know if you have a history of blood clots. Also, tell your doctor or nurse about any of these symptoms as soon as possible.

These are signs of a blood clot in the lungs.

• Shortness of breath

• Coughing up blood

These are symptoms of a blood clot in the legs.

• Pain

• Swelling

• Tenderness in the groin or legs

Effects on the Eye

Tamoxifen can cause cataracts or changes to parts of the eye such as the cornea or retina. Tell your doctor or nurse about any vision changes--including an inability to tell the difference between colors.

Signs of Stroke

Tamoxifen increases a woman's chance of having a stroke. Tell your doctor and get medical help right way if you have any of these symptoms.

• Weakness

• Difficulty walking or talking

• Numbness