Treatments for breast cancer can affect the ovaries in a number of ways. These effects can be temporary or permanent.
- Temporary or permanent menopause can occur in women receiving chemotherapy given to reduce the chance of the breast cancer coming back or spreading.
- Women with hormone sensitive cancers will usually be advised to take anti-oestrogen treatments such as tamoxifen, goserelin or aromatase inhibitors. These anti-oestrogen treatments will affect the ovaries and commonly cause menopausal symptoms for the duration of their use. When these anti-oestrogens are stopped, periods (and fertility) may return, but this is very difficult to predict.
- Temporary menopause is more common among women who are younger than 35 at the time of treatment. If menopause is temporary, menstrual periods may return within 1 year of stopping treatment. Permanent menopause is more common among women who are 40 or older at the time of treatment.
- There is no reliable test to predict whether menopause will be temporary or permanent. Although normal menstrual periods may return once treatment finishes, menopause may be permanent, regardless of age.
- Permanent menopause also occurs in women who have surgery to remove the ovaries, or radiotherapy to the ovaries.
Regardless of whether menopause is temporary or permanent, you may experience menopausal symptoms during treatment. Some women who have already gone through menopause also experience menopausal symptoms with certain treatments. For example, drugs such as tamoxifen, goserelin and aromatase inhibitors – anastrozole, letrozole and exemestane – can cause symptoms such as hot flushes. These symptoms usually stop once treatment finishes.
Which breast cancer treatments cause menopause?
The likelihood of breast cancer treatment causing menopause depends on the type of treatment and your age when treatment starts.
Surgical removal of the ovaries. As part of breast cancer treatment, you may be offered surgery to remove your ovaries (oophorectomy). If you are pre-menopausal, removal of the ovaries will bring on permanent menopause and will cause a sudden and permanent drop in your hormone levels.
Radiotherapy to the ovaries. You may be offered radiotherapy to your ovaries to stop your ovaries from working. This is different to having radiotherapy to the breast. Radiotherapy to the ovaries stops them from producing and releasing hormones and results in a permanent menopause.
Chemotherapy. Many different chemotherapy drugs are used in the treatment of breast cancer. Not all chemotherapy drugs cause early menopause or menopausal symptoms. Chemotherapy treatments change all the time – and so too does the risk of early menopause or menopausal symptoms.
Hormonal therapies. Hormonal therapies (also called endocrine therapies) may be given to women who have hormone receptors on their breast cancer cells. Hormonal therapies work by blocking the action of oestrogen. Some hormonal therapies can cause menopausal symptoms in younger women. Examples of hormonal therapies include goserelin, tamoxifen and aromatase inhibitors. Hormonal therapies can also cause menopausal symptoms even in women whose periods stopped some years before they were diagnosed with breast cancer.
Effects of breast cancer treatments on fertility
Some treatments for breast cancer can affect your fertility (your ability to have children).
Once your cancer treatment has finished there is no reliable test to find out if you can still become pregnant. If your periods stop for a year or more, it’s more likely that your menopause will be permanent. If your menopause is permanent, you will be unable to get pregnant naturally.
If being able to have children is important for you, speak to your treatment team about fertility and family planning before starting treatment for breast cancer. Your oncologist may suggest that you see a fertility specialist to discuss your options.
Contraception after breast cancer treatment
Treatments for breast cancer may reduce fertility temporarily or permanently. However, this does not mean it is impossible to become pregnant during or after treatment.
Contraception containing hormones, such as the oral contraceptive pill (‘the pill’), implants or injections, should generally not be used after breast cancer. Therefore it’s recommended that you use non-hormonal forms of contraception, such as condoms, diaphragms, intrauterine contraceptive devices (IUDs) or male or female sterilisation if you don’t want to become pregnant. It’s still possible to catch sexually transmitted infections (STIs) after menopause. Condoms are the most effective way of protecting against STIs.
If you were pre-menopausal before breast cancer and you are sexually active, talk to a member of your health care team about suitable methods of contraception for you.