Hormonal therapies are usually recommended for women who have hormone receptors on their breast cancer cells. Your doctor will also consider the risk of your breast cancer coming back, and your general health. Some of the things that affect your risk of breast cancer coming back include its size, grade and whether it has spread to any lymph nodes. This information is listed in your pathology report. You can request a copy of your pathology report from your doctor.
The types of hormonal therapies recommended for an individual woman will depend on whether she has reached menopause. If you are not sure whether you have reached menopause, talk to your doctor.
If you have not yet reached menopause and your cancer cells have hormone receptors:
- It is usually recommended that you are treated with tamoxifen.
- If you are at very low risk of the breast cancer coming back (eg, if your breast cancer is very small and has not spread to your lymph nodes) your doctor may not recommend tamoxifen for you.
- Your doctor may discuss taking part in international trials comparing different combinations of chemotherapy, anti-ovarian treatment and anti-oestrogens.
- Your doctor may recommend an anti-ovarian treatment; additional treatment with tamoxifen may also be recommended for you.
If you have not yet reached menopause and having children is important to you, you should discuss your options with your doctor before starting hormonal therapy.
If you have reached menopause and your cancer cells have hormone receptors:
- It is usually recommended that you are treated with either tamoxifen or with an aromatase inhibitor.
- If the risk of breast cancer coming back is very low (for example, if your breast cancer is very small and has not spread to any lymph nodes) your doctor may not recommend hormonal therapy for you.
After menopause: which hormonal therapy?
When deciding which hormonal therapy to recommend for your individual situation, your doctor will consider its likely benefits and possible side effects (both known and unknown).
The long-term benefits and risks of taking tamoxifen are well established. Tamoxifen reduces the risk of breast cancer coming back and lowers the risk of dying from breast cancer.
Studies have shown that treatment with an aromatase inhibitor reduces the risk of breast cancer coming back more than tamoxifen. These studies have not been going long enough to say whether aromatase inhibitors improve survival more than tamoxifen. Also, the long term side effects of aromatase inhibitors are not yet known.
For women with a higher risk of their breast cancer coming back, the short-term benefits of treatment with an aromatase inhibitor are already sufficient to outweigh the risks of side effects (both known and unknown).
For women with a lower risk of their breast cancer coming back, it is still possible that long-term side effects of aromatase inhibitors (as yet unknown) will outweigh the short-term benefits of treatment compared with tamoxifen.
What if I am already receiving tamoxifen?
If you have reached menopause and started tamoxifen less than 5 years ago, then you may benefit from changing your treatment to an aromatase inhibitor. The decision about whether to change to an aromatase inhibitor will depend on your level of risk of breast cancer coming back – the higher your risk, the more likely it is that your doctor will recommend that you change treatments.
If you have reached menopause and have recently completed 5 years of treatment with tamoxifen, then you may benefit from receiving further treatment with an aromatase inhibitor. The decision about whether to have further treatment with an aromatase inhibitor will depend on your level of risk of breast cancer coming back – the higher your risk, the more likely it is that your doctor will recommend that you have further treatment.
Questions yet to be answered about aromatase inhibitors
As with many drugs available to treat breast cancer, there are important things that we still don’t know about aromatase inhibitors. Clinical trials to answer these questions are ongoing and more information will become available in the future.
Some of these questions include:
- the ideal length of time for which an aromatase inhibitor should be taken (at the moment aromatase inhibitors are usually prescribed for 5 years)
- whether it’s better to use tamoxifen and an aromatase inhibitor in sequence (one after the other) and if so, in which order
- the effects of aromatase inhibitors on memory, concentration and heart disease
- how best to manage the loss in bone strength caused by aromatase inhibitors
- whether hormonal therapies can be used to prevent breast cancer in women who have not been diagnosed with the disease.
Questions to ask your doctor about hormonal therapies
The following questions may be useful for you when discussing hormonal therapies with your oncologist, breast care nurse or general practitioner:
Before treatment
- How can I benefit from hormonal therapy?
- Which hormonal therapies are suitable for me? Why?
- What does the hormonal therapy you are recommending involve?
- How much will the hormonal therapy you are recommending cost?
- What are the most common and rarer side effects of the hormonal therapy you are recommending?
- Who should I contact if side effects happen?
- How can I manage side effects if they develop?
- Will the side effects stop when I finish treatment?
- When will I start hormonal therapy if I am having other treatments?
- Will hormonal therapy affect my ability to have children?
- Do I still need to use contraception if I am having hormonal therapy?
Once treatment has started
If you decide to take a hormonal therapy such as tamoxifen or an aromatase inhibitor, you will probably be advised to take it for 5 years. During this time, you may have questions about side effects. It is important that you discuss any questions or concerns you have with your oncologist or general practitioner – even if these questions arise several years after you start treatment. Listed below are some frequently asked questions that may be relevant for you in the coming years.
Question: If I experience side effects, can I lower my dose of hormonal therapy?
Answer: The recommended doses are the only ones tested – taking lower doses or less frequent doses is not a good idea. If you have side effects, it is important that you discuss them with your oncologist, surgeon or general practitioner.
Question: If I run out of my script, can my GP renew it?
Answer: Yes.
Question: If I am planning to have surgery (including dental surgery) can I continue to take my hormonal therapy?
Answer: Some hormonal therapies can increase the risk of blood clots. If you are likely to be confined to bed or have limited movement, your doctor may recommend that you stop taking your hormonal therapy for a period of time before surgery and that you do not start taking it again until you are fully mobile after surgery.
Question: If I miss a dose of my hormonal therapy, should I take a double dose?
Answer: No. Just take the next dose as normal.
Question: If I change from tamoxifen to an aromatase inhibitor, can I change back later if side effects worry me?
Answer: Yes.
