Published: 23-02-2022 11:20 | Updated: 08-03-2022 14:29

Fertility treatment: Help for people who have had cancer

Many young people whose fertility have been impaired due to cancer treatment can today be helped to become parents. Kenny Rodriguez-Wallberg, Adjunct Professor at the Department of Oncology and Pathology at Karolinska Institutet and Senior Consultant at Karolinska University Hospital, answers six common questions.

Kenny Rodriguez-Wallberg
Kenny Rodriguez-Wallberg Photo: Stefan Zimmerman

Text: Annika Lund, in translation from Swedish for the magazine Medicinsk Vetenskap no 1/2022 |
Spotlight on infertility

Why does cancer damage fertility?

“Usually it’s the treatment that affects the reproductive organs. Surgery and radiation can cause damage if the treatment is targeted towards the ovaries or testicles, for example. Fertility can be protected by being less radical during surgery and avoiding certain areas in radiotherapy. But some chemotherapy damages ova, for example, and we can’t protect the patient from that. These are cells that won’t be formed again during the patient’s lifetime.”

What treatment can you offer?

“For men and teenage boys, we can freeze sperm. For adult women, we can freeze eggs, embryos or ovarian tissue. We can also freeze the ovarian tissue of younger girls. The tissue can then be restored through surgery, e.g. once the girl has become an adult and wants children. In 2019, the first baby was born in Sweden following the freezing of ovarian tissue to preserve the fertility of a girl with childhood cancer.”

Why is this important?

“Cancer therapies are now so effective that 85 percent of people are expected to survive the disease. Young long-term survivors have described the pain of not being able to have a family, some finding it more painful than having cancer. Therefore, in the last couple of decades we have developed methods to preserve the fertility of young cancer patients and other young people with reduced fertility.”

So how does it work?

Because cancer treatment often starts very soon after diagnosis, doesn’t it? “Yes we have to work fast. In Sweden, fertility clinics at the university hospitals can admit these patients as an emergency. After receiving counselling, the patient needs to say yes or no to the treatment pretty much immediately. A sperm sample can be provided instantly and ovarian tissue can be taken for freezing as soon as possible. Hormone stimulation to obtain mature eggs takes about two weeks and can also be started immediately. There is no need to wait for a particular phase of the menstrual cycle. This is one of the things that we have only understood quite recently thanks to our research.”

Is this offered to all Swedish cancer patients?

“Generally, yes. Everyone must be informed that cancer treatment can affect fertility and be offered a referral to a fertility centre. All patients have the right to know what side-effects treatment may have. They have the right to know that their hair will fall out and that they may be infertile. This applies whether or not any measures to preserve fertility can be offered.”

How effective are these treatments to preserve fertility?

“In 2019, we published a review of just over 1,200 girls and women who had received counselling on fertility preservation methods at Karolinska University Hospital between 1998 and 2018. Two-thirds had previously been treated for cancer while the rest had another disease that affects fertility such as Turner syndrome. Those who had previously had cancer were older when they came back to attempt to conceive and their treatments more rarely resulted in childbirth and a baby. But in the group as a whole, about half of those who used frozen embryos or eggs had a baby while fewer than one in ten women whose ovarian tissue was reimplanted had a baby. These figures are sure to change as when we compiled the data, many of the group were too young to be planning a pregnancy.”

How safe are these treatments?

“We have developed methods where women with hormone-sensitive breast cancer can receive hormone stimulation to produce eggs. In such cases, hormone stimulation is given with the addition of drugs that reduce the amount of oestrogen in the body. Our research has shown that this addition means that the women have the same amount of oestrogen in their blood as in a normal menstrual cycle, but more eggs mature at the same time. Studies that follow patients in this situation show that it does not have a negative impact on the cancer prognosis.”

What will you be researching next?

“There isn’t any treatment to help younger boys. At the moment we freeze testicular tissue to save cells that are intended to produce sperm after puberty but we need to do more research to find out how to reimplant them. Transplanting ovarian tissue is not that effective at the moment and here a trial is in progress to pre-treat the tissue before freezing. We also need to develop methods to help women whose womb has been damaged by radiation. It is also important to continue to monitor the treatments we provide to constantly check how safe and effective they are. We need to build up a quality register.”