Professor Hamish Wallace is a Consultant Paediatric Oncologist at the Royal Hospital for Children & Young People in Edinburgh and honorary professor at The University of Edinburgh. He explains what fertility preservation options are available for young cancer patients.
For children, young people and their families, a diagnosis of cancer is both devastating and frightening. The future is uncertain and there is so much to quickly learn and understand. Most young people with cancer will start a treatment plan with a combination of chemotherapy, surgery and sometimes radiotherapy. Doctors will explain the nature of their cancer and, if it is a solid tumour, will investigate whether the tumour has spread elsewhere throughout the body. This involves tests, scans and assessments as part of diagnosis which can take time and and can be an anxious wait for families. There is lots of information to take in at once and it can be difficult to think ahead to the future when a young person may want to start a family of their own. However, families are asked to consider this possibility before treatment even starts.
Talking about fertility preservation with families.
As we expect most young people with cancer to be successfully treated and go on to lead a healthy life, it is important that a discussion takes places as soon as possible about how the intended treatment might affect their future chances of either fathering a child or having a baby.
While many cancer treatments are unlikely to affect fertility, there are some treatments that can cause long-term or permanent damage to fertility. As such, it is important for all young people with cancer and their families to have the opportunity to discuss their future fertility prospects with their doctors and nurses before treatment begins.
This discussion is seen as a positive one because the doctors and nurses believe it is important to the child or young person’s future, and that the opportunity to either father a child or have a baby will matter to them in later life.
What can be offered to girls and young women to preserve their future fertility?
Fertility preservation means storing one of the following before treatment:
- eggs
- embryos (eggs fertilised with sperm)
- ovarian tissue
If there is a high risk of infertility and premature ovarian insufficiency (POI, or premature menopause), there are both established and experimental options.
For older girls who have undergone puberty and have a partner, they can be referred to an infertility unit to start hormone treatment to mature an egg.This egg can be taken out and fertilised with their partner’s sperm to create an embryo which can then be frozen and stored. 'Embryo freezing' is very successful; they can survive for many years, and after thawing placed back inside of the uterus for fertility long after cancer treatment is completed. This fertility option can only happen if enough time is available before treatment starts.
For older girls who have undergone puberty and do not have a partner which is more common, there is the option of 'egg freezing'. New egg freezing techniques (vitrification) are improving the chances of a frozen then thawed mature egg of being successfully fertilised to create an embryo, which can then be placed back in the uterus in the hope of successfully achieving pregnancy. However, there needs to be time to delay the start of the cancer treatment so the patient can receive hormone stimulation and egg collection in the infertility unit. This can take at least two weeks.
For younger girls who have not started puberty but are at a high risk of infertility and POI ovarian tissue, 'cryopreservation' can be considered, though this remains experimental. It is an additional keyhole surgery procedure under general anaesthetic. Either samples of ovarian tissue can be taken from one ovary and frozen, or a whole ovary can be removed, and then frozen in the laboratory. Later, when the young woman wishes to start a family, the tissue can be thawed and transplanted under a general anaesthetic into her pelvis.
We don’t yet know how successful this procedure will be in preserving fertility for pre-pubertal girls, but there have been several hundred babies born worldwide after the transplantation of frozen thawed ovarian tissue taken from post-pubertal women. This gives us good reason to hope that it is likely to be successful and allows the young woman the chance of a pregnancy, once she is cured of her original cancer.
What can be offered to boys and young men to preserve their fertility?
For young men with a new diagnosis of cancer who have undergone puberty and are able to masturbate and produce semen before starting their treatment, we offer all patients 'semen cryopreservation', which is established and successful, even if there is a low risk of infertility. The sperm can be safely frozen for many years and once thawed can be used to fertilise an egg using in vitro fertilisation (IVF). Usually, semen samples are provided by masturbation in a private room in the fertility clinic.
Some young men are unable to produce samples by masturbation, but it may be possible for a specialist doctor to collect sperm from the testicle under sedation or a general anaesthetic. It is not recommended to bank sperm after chemotherapy has started.
Freezing sperm is a positive thing to do, but it is not easy having received the news of a cancer diagnosis and that treatment is needed with lots of potential side effects. It can be difficult for young men to go to the infertility unit and produce a semen sample when they feel ill and scared. Hospitals where young men are being treated for cancer offer this service and have appropriate counselling available to support these young men at a very difficult and challenging time.
For younger boys who have not started puberty but are at high risk of infertility, there are currently no established options available. In some hospitals, under the process of a clinical trial, a pre-pubertal testicular biopsy and freezing is being offered. This is carried out by a paediatric surgeon under a general anaesthetic. We do not yet know if this frozen pre-pubertal tissue will preserve future fertility, and this is an important area of active research.
Boys
In boys who have not started puberty, testicular biopsy and cryopreservation is an experimental option. In boys and young men who have started or undergone puberty, the ability to produce a sperm sample enables sperm cryopreservation: if this is not possible, testicular biopsy with cryopreservation of sperm or tissue is needed.
Girls
In girls who have not started puberty, ovarian stimulation is inappropriate, so ovarian tissue cryopreservation can be considered but remains experimental. After puberty, egg or embryo cryopreservation is an established option.
From Contact magazine issue 94 - Spring 2022
