March 2016 Ask the Expert: Hormonal Therapy

March 1, 2016

Hormonal therapyinfo-icon is medicineinfo-icon or surgeryinfo-icon that lowers the amount of estrogeninfo-icon in the body. Your doctor may also call this type of treatment endocrineinfo-icon or anti-estrogen therapyinfo-icon. It is used for cancers that are hormone receptorinfo-icon-positive, meaning they depend on estrogen or progesteroneinfo-icon to grow. Hormonal therapy is used to lower the risk of recurrenceinfo-icon in early-stage breast cancerinfo-icon and to slow growth in 
metastaticinfo-icon breast cancer.

In March, Living Beyond Breast Cancer expert Jennifer L.A. Armstrong, MD, answered your questions about hormonal therapy, including what treatments may be used, who may get it, why it may be offered and how it could affect the rest of your treatment and your risk of recurrence.

Remember: we cannot provide diagnoses, medical consultations or specific treatment recommendations. This service is designed for educational and informational purposes only. The information is general in nature. For specific healthcare questions or concerns, consult your healthcare providerinfo-icon because treatment varies with individual circumstances. The content is not intended in any way to substitute for professional counselinginfo-icon or medical advice.

If I’m able to take tamoxifen or an aromatase inhibitor, how am I supposed to choose which to take? Do tamoxifen and aromatase inhibitors work equally well? Is one likely to have worse side effects than the other?

Aromatase inhibitors (AIs) only work in postmenopausalinfo-icon women. Tamoxifeninfo-icon works in postmenopausal and premenopausalinfo-icon women. So it is postmenopausal women who have the option between tamoxifen and AIs.

There is data that suggests AIs work better than 5 years of tamoxifen. But now that there is data to support 10 years of tamoxifen, we do not know if 5 years of AI or 10 years of tamoxifen is better. Those trials have not yet been done.

For some women, the decision comes down to side effects. Tamoxifen protects the bones from osteoporosisinfo-icon. The AIs cause mild to severe joint aches in 30 to 70 percent of patients. (This varies depending on the study and method of reporting.) Because of this, many women with severe osteoporosis or arthritis opt for tamoxifen over AIs. But, because tamoxifen causes twice as many blood clots as AIs (4 percent vs. 1 to 2 percent), many women with a personal or family history of blood clots choose AIs. And tamoxifen slightly increases the risk of uterine cancer, so patients with concerns about this may opt for AIs.  

Some women start with one and wind up switching to the other due to side effects (and this is OK)!

Are there long-term side effects or problems that can happen from limiting the amount of estrogen in my body?

There is concern that risk of stroke or heart attack may be increased slightly but studies are ongoing to look into this further. Similarly, there may or may not be an increased risk of cataracts, a cloudiness that forms in the lens of the eye and affects vision. For this reason, it’s recommended that patients on hormonal therapyinfo-icon have an annual eye exam with an ophthalmologist.

Can the aromatase inhibitor anastrozole (Arimidex) or other hormonal therapies cause side effects related to memory, thinking or the way the brain works?

We are not entirely sure. While patients often report this, studies have failed to show a cause-and-effect relationship. But this is being intensely investigated, and the data is evolving. Stay tuned… 

I am coming up on 5 years of tamoxifen. How do I know if I should continue it for another 5 years, if I should switch to an aromatase inhibitor, or if it’s OK for me to stop getting hormonal therapy treatment?

It can be very hard to know the answer to this, because we do not yet have randomized studies comparing these options to each other. Often when a patient has a higher risk of recurrenceinfo-icon, a more aggressiveinfo-icon (and longer) course of anti-estrogeninfo-icon therapyinfo-icon is recommended. How strongly hormoneinfo-icon-receptorinfo-icon positive a tumorinfo-icon is may also be taken into the equation.

In other words, a discussion with your team is needed to understand how the details of your tumor, and your health, may affect this decision.

How would taking an aromatase inhibitor for 5 years affect my risk of recurrence? Do different aromatase inhibitors affect risk of recurrence differently?

AIs reduce the risk of recurrenceinfo-icon by about a third to one half, in general. Age and specifics of the tumorinfo-icon affect this as well, and should be discussed with your team.

There has not been one AI that has been shown to be best in overall survival (helping people live longer), compared to another AI.

I had been taking hormone replacement therapy, but I was taken off of that after I was diagnosed with breast cancer. I now have 10-15 hot flashes a day and do not sleep because of them. Some make me nauseous and light headed and I have gained 25 pounds. What can I do to help lessen these effects?

There is a lot that can be done to reduce hot flashes. Reducing or avoiding  caffeine and increasing exercise (to walking or running 10 miles a week, or another form of and amount of exercise that is equally challenging) can work quite well.

Patients are often surprised that one cup of coffee in the morning can lead to hot flashes that awaken them from sleep in the middle of the night, but this can happen.

There are also drugs that can help with hot flashes, especially SSRIs (such as venlavaxine, citalopram, or escitalopram). These medicines are most often used for depressioninfo-icon and anxietyinfo-icon, but you don’t have to have those conditions to take them. Your medical team may be able to suggest other medicines that can also help, so talk to them about how you’re feeling.

I was premenopausal when I started taking tamoxifen at age 45. I'm now 50. How do I know if I can still get pregnant?

It can be very hard to know. On the one hand, it is recommended that people in this situation still use contraception if they do NOT want to get pregnant. On the other hand, for patients who wish to become pregnant, referralinfo-icon to a gynecologist, an infertilityinfo-icon specialistinfo-icon, or both, can be very helpful.

While there are hormonal levels that can be measured, recent studies have shown these hormonal levels (FSH and LH especially) are less predictive in this setting than in patients without a history of treatment for breast cancer.

Can the amount of estrogen in my body be measured with blood tests? What should my level of estrogen be if I’m taking hormonal therapy?

At this time, there is not data to support testing of estrogeninfo-icon levels in the body as a guide for dosing or other monitoring of anti-estrogen therapyinfo-icon.

I’m considering removing my ovaries to lower my estrogen levels. Should I have my uterus and fallopian tubes removed too? What are the pros and cons?

It is not standard to remove the uterus and fallopian tubes when considering oophorectomyinfo-icon (removing the ovaries to reduce estrogeninfo-icon levels). Unless there are other medical issues unrelated to breast cancer, the risks of this kind of extensive surgeryinfo-icon are felt to outweigh the benefits. But discussing this further with your medical team is recommended.

Is it better to suppress the ovaries with medicine, or to remove them with surgery?

We are not entirely sure, but it is important to note that shutting down the ovaries with medicineinfo-icon (called chemical ovarian suppressioninfo-icon) is reversible. Shutting down the ovaries with surgeryinfo-icon is not reversible. That concern may be more relevant to patients with early-stageinfo-icon disease than those with metastaticinfo-icon disease.

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