For a woman of child bearing age, a diagnosis of breast cancer can cause a natural anxiety about the risk of infertility. A treatment regime of surgery and radiotherapy is unlikely to result in fertility issues, but if you need chemotherapy or certain hormone therapies, your fertility may be affected.
Speak to your oncologist about the potential impact on your fertility of the treatments offered. In addition, you may want to seek the advice of a fertility specialist to further discuss your options for fertility preservation. In New Zealand, women experiencing breast cancer are entitled to a funded consultation with a fertility specialist so it’s a good idea to take advantage of this if you are young and might want children in the future.
On this page we outline:
- the potential impacts of chemotherapy on fertility
- the fertility treatment options available to women who want to have children after breast cancer treatment
- getting pregnant after treatment
- the impact of hormonal therapies on fertility
The impact of chemotherapy on fertility
Chemotherapy combinations typically used for early breast cancer are likely to cause at least temporary amenorrhoea (cessation of periods) in most women under the age of 50. The likelihood of your normal periods returning after chemotherapy is affected directly by your age. For example, in women under 40 whose periods stop after treatment with the common breast cancer chemotherapy combination, FEC, this is reversible in more than 75 per cent of cases. However, amenorrhoea following the same treatment in an older woman is reversible in less than 20 per cent of cases.
So, the older you are, the more likely the ovarian shut-down is to be permanent. As a general rule, women 35 and over are more like to experience permanent ovarian shut-down and infertility.
If you have not had children and think this is something you would like to do in future, then these statistics can be worrying. Make sure you have a comprehensive discussion with your oncologist about fertility issues. Some chemotherapy drugs cause more damage to eggs than others, so you may be able to undertake a chemotherapy regime which has a lower-risk of egg damage.
Fertility treatment options available
There are a number of fertility preservation options open to younger women who have been diagnosed with breast cancer. Below, Dr Mary Birdsall, a fertility specialist with Fertility Associates, outlines the options currently available.
Women with breast cancer who are undergoing chemotherapy are able to have a funded consultation with a fertility expert in order to discuss their options.
The alkylating agents in chemotherapy such as cyclophosphamide will cause some or all of the eggs in the ovaries to be destroyed. Women are born with a fixed number of eggs and so there is no opportunity for regeneration of eggs. The impact that chemotherapy will have on an individual's eggs depends on the dose, the age of the woman and how many eggs she has. Even when a woman resumes menstruation post chemotherapy, her reproductive window is likely to considerably reduced. If a woman wants to have eggs, embryos or ovarian tissue frozen it is ideal to do this prior to chemotherapy being given.
Options for women in this situation include:
- do nothing except getting on with their breast cancer treatment
- consider using a donor egg after treatment if they are found to be menopausal
- have embryos frozen before treatment
- have eggs frozen before treatment
- have ovarian tissue frozen before treatment
Egg donation is where another woman goes through an in vitro fertilization (IVF) cycle, a batch of her eggs is collected, fertilised with the recipient's partner’s sperm and the consequent embryos are placed into the recipent's uterus. This may be funded for up to two cycles provided the recipient is aged less than 40. Success rates are related to the age of the egg donor but typically would sit at around a 40% live birth rate per cycle.
The second option is to undergo a cycle of embryo freezing prior to the start of chemotherapy. This option involves having ovarian stimulating drugs for about two weeks, then your own eggs are harvested, fertilised with your partner's or donor sperm and the embryos frozen. Embryo freezing may be funded but is not always an option for all because of time constraints, a partner is required and ideally the breast cancer should be oestrogen receptor negative.The chances of a pregnancy resulting from one cycle of embryo freezing are related to your age and if you are 36 or younger would be just under 50 per cent. If a woman has a hormone dependent breast cancer, there are some more experimental stimulation regimes which may be considered.
Option number three is egg freezing. This is not currently funded in New Zealand, although the Minister of Health has been asked to provide funding. Once again ovarian stimulating drugs are used for around two weeks, the eggs are collected and then frozen. This technology is new and there have been fewer than 1000 babies born worldwide using this technology so it is impossible to give success rates. This is also not always an option as some time is needed resulting in a delay in treatment of the cancer and the use of fertility drugs may be risky for women with hormone dependent cancers. The cost is around $9000 and then a further $2000 for thawing and replacement in the uterus.
We are also able to freeze ovarian tissue obtained via a laparoscopy. This tissue may then be reimplanted at a later date. This technique is very experimental with only 12 pregnancies reported to date. No funding is available. The advantage of this option is that it does not require ovarian stimulating drugs.
Finally, there is also interest in the concept of chemoprotection, which is when a medication called a Gonadotrophin Releasing Agonist is given at the same time as chemotherapy and may provide some protection to the eggs. Several large clinical trials are under way around the world to determine the efficacy and safety of this option. The drugs used in this technique are funded.
Any tissue frozen in the options listed above is stored in liquid nitrogen at minus 196 degrees centrigrade and may be frozen indefinitely. There is however legislation in New Zealand which limits storage to 10 years although an extension may be applied for.
It remains my aim that all women who have not completed their families and who are facing cancer treatments which may compromise their fertility options would have the opportunity to discuss their options with a fertility expert.
Getting pregnant after treatment
Women who get their period again after chemotherapy treatment need to be careful about birth control. Even though you are menstruating again, the chemotherapy treatment could have caused damage to eggs which may result in birth defects if you become pregnant. Doctors generally advise that you wait for a certain length of time after chemotherapy treatment before trying to get pregnant. Speak to your doctor for more information on this.
There is no higher risk of relapse for the breast cancer survivor who becomes pregnant at a later time, although many oncologists will recommend that pregnancy is delayed until after the period of highest risk of relapse (the first 2-2.5 years). This minimises the likelihood of being diagnosed with relapsed breast cancer during pregnancy, which is a very challenging situation for both the patient and their oncologist.
Hormone treatments after chemotherapy
Hormone treatments, such as tamoxifen, Arimidex, DP Anastrozole, Aromasin or Femara, aim to reduce the risk of breast cancer recurring by limiting the production of oestrogen in the body. These therapies are used for women who have breast cancer that is driven by the hormone oestrogen and are generally taken for a period of five years or more.
However, these treatments can result in your periods stopping temporarily or they may result in early menopause for young women. Not all women will experience early menopause with these treatments, but some will. If you think you may want to get pregnant after your primary treatment for breast cancer then you will need to discuss the option of hormone therapy carefully with your doctor.
It is not safe to become pregnant while taking any of these medications. They can cause damage to the developing foetus resulting in birth defects.
Hormone treatments can reduce the chance of breast cancer recurring so you will have to weigh the pros and cons of hormone therapy with the pros and cons of fertility preservation. Have an in-depth discussion with your oncologist and a fertility specialist. You may also benefit from talking with a counsellor to work through the issues that are most important to you.
You might also like to read the section on fertility preservation.
Hormone treatment during chemotherapy
There has been some exploration of the option of reversible ovarian suppression i.e. blocking ovarian function with luteinising hormone-releasing hormone (LHRH) agonists while receiving chemotherapy, in the hope of more effectively preserving fertility. However, there are some concerns with this approach:
- Some of the drugs used for chemotherapy in breast cancer still cause gene damage when cells are not growing and thus suppression will not completely protect the oocytes (eggs)
- The use of LHRH agonists to suppress ovary function e.g. using Zoladex, can result in a flare in hormones that might drive hormone-sensitive tumour cells
- Hormonal therapy using other agents, e.g. tamoxifen concurrently with chemotherapy has been shown to worsen outcomes
- The only randomised trial of this approach was negative and other reported trials have major design problems
Because of these concerns most authorities advise against the use of ovarian suppression as a means of preserving fertility when a young woman is receiving chemotherapy for early breast cancer.