Cancerous tumours and cancer treatment can affect the ability to conceive a child or maintain a pregnancy to differing degrees. — Photos: dpa
CERTAIN cancers and their treatment can cause infertility in both males and females. But there’s a way to preserve it: a process called cryopreservation, in which sperm or unfertilised eggs are frozen and stored at extremely low temperatures in liquid nitrogen for future use.
When eggs or sperm can’t be collected for some reason, ovarian or testicular tissue can also be frozen in this way in an effort to preserve fertility.
”Fertility preservation is very important for the many cancer patients who still want to have children,” says Felix Pawlowski, spokesman for the German Foundation for Young Adults with Cancer (DSFJEMK).
”The moment they receive a cancer diagnosis, many don’t think about life after the disease,” which he says is why the possibility of freezing gametes (egg or sperm cells) or reproductive organ tissue is so psychologically valuable too: It gives patients a prospect for their life after treatment.
Cancerous tumours and cancer treatment can affect the ability to conceive a child or maintain a pregnancy to differing degrees.
”The degree of risk that you’ll become infertile depends on the organ affected and treatment used,” says Susanne Weg-Remers, head of the Cancer Information Service at the German Cancer Research Centre (DKFZ). The attending physician can weigh the patient’s risk and how to preserve their fertility.
For women, the most common method of fertility preservation is to retrieve unfertilised eggs and storing them for future use.
Greater risk
The risk is greater, according to Weg-Remers, if the tumour affects the brain or certain structures that regulate hormone metabolism.
”Reduced fertility can also result if the tumour affects the ovaries, uterus or cervix,” she says. For men, testicular or prostate cancer can cause fertility problems.
Cancer treatment can have an adverse effect on fertility as well. Chemotherapy, for example, can impair the functioning of ovaries or testicles. “Many women temporarily stop menstruating after chemotherapy,” Weg-Remers notes.
Chemotherapy can damage sperm and lower sperm count to the point of making men infertile. The same goes for some radiation and hormone therapies.
”After a cancer diagnosis, the attending physician should discuss initiating fertility protection and preservation measures with the patient as soon as possible,” says reproductive physician Dr Ralf Dittrich, head of the In Vitro Fertilisation and Endocrinology Laboratory at Erlangen University Hospital in Germany.
This also applies when starting a family still lies in the patient’s distant future.
The urgency of treatment depends on the cancer type, Dittrich points out. Enough time often remains to extract gametes or reproductive organ tissue. “Extracting sperm from postpubescent males is relatively uncomplicated and doesn’t take much time,” he says.
In the face of cancer, cryopreservation offers a way to preserve fertility. — Photos: dpa
Extract and freeze
For females, the most common fertility preservation method is to extract and freeze unfertilised eggs.
”The ovaries are stimulated with the relevant hormones,” Dittrich says. This induces them to produce multiple eggs, which are harvested from the follicles transvaginally using a thin, hollow needle attached to a catheter with suction capabilities. The eggs are then cryopreserved.
”When quick action is needed, extraction of ovarian tissue is advisable instead, since there’s often too little time for the hormone therapy preceding egg retrieval,” Weg-Remers says.
Moreover, the hormones oestrogen and progesterone, which are used in the therapy, can stimulate the growth of breast cancer cells.
Extraction of ovarian tissue involves a minor surgical procedure performed under general anaesthesia. The surgeon makes a small incision in the abdomen and uses a laparoscope to remove tissue from the egg-producing portion of an ovary, which is then frozen.
After cancer treatment has been completed, the tissue is thawed and reimplanted in the patient, ideally close to the remaining ovarian tissue.
An important function of the ovaries is production of hormones that control a woman’s menstrual cycle.
Reimplantation of previously frozen ovarian tissue can restore this function and, if all goes well, ovulation resumes. As long as the fallopian tubes haven’t been damaged by the cancer treatment, pregnancy can occur naturally again.
In males, testicular tissue is extracted and cryopreserved in the rare cases when isolating sperm isn’t possible, for example in boys who haven’t yet reached sexual maturity.
”If the patient – male or female – is very young, chances are quite good they can fulfil a desire to have children after cancer treatment,” Dittrich says. But the older the patient is, particularly women, the lower the probability of remaining fertile – which is also true of healthy women, of course.
Until the age of 38, women normally have a good chance of getting pregnant despite the natural ageing process of their eggs, points out Dittrich.
”Although the likelihood of becoming pregnant (via cryopreservation) after cancer treatment unfortunately diminishes considerably due to the interventions and age, it’s definitely not hopeless,” he says. – dpa/Lorena Simmel
