Information on embryo freezing and infertility treatment for cancer patients

Cancer or its treatment can sometimes affect a person’s ability to have children. However, developing cancer does not necessarily mean you can never have children again. This article shares information about embryo freezing , the most frequently used option to preserve fertility before treatment when fertility may be affected.

During development in the womb, between weeks 2 - 8, the offspring is called an embryo . Fertilization, normally occurring within the mother’s body, can be replicated outside the body in specialized laboratories. Resulting embryos can be transferred to the prospective mother for pregnancy or frozen for later use. Embryo freezing may be performed for future pregnancies, donation to others or research.

How is an embryo created?

A certain number of eggs must be collected from the woman’s ovarian reserve for fertilization. Medicines and hormones increase production of eggs with fertilization potential. These eggs are collected for fertilization and prepared in the laboratory.

Fertilization outside the body is performed in two ways: IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection). In IVF, collected eggs are mixed with sperm in the laboratory. After 16-20 hours, the egg is expected to enter the sperm. In ICSI, sperm is injected directly into the egg. ICSI is preferred more often if IVF fails or sperm movement or structure is abnormal.

How is freezing performed?

The aim is long-term embryo preservation. The greatest problem, however, is water inside cells. As it freezes, it forms crystals, causing cells to burst and die.

• To prevent crystallization, water within the embryo is replaced with cryoprotectant , a fluid that prevents freezing.
• Slow freezing: Temperature is lowered gradually to minimize embryo damage.
• Vitrification: Cooling occurs very rapidly, freezing water molecules before crystals can form. Less damage occurs upon thawing for use. It is relatively more successful than slow freezing.

Who should consider it?

This method can in fact be performed for any woman, but is especially beneficial for certain patient groups. It may be considered in ovarian hyperstimulation syndrome or when medicines affecting reproduction are used (such as chemotherapy drugs in cancer patients).

Although cancer is generally a disease of older age, people now have children later because of working life, later marriage and similar factors. Relatively more people therefore develop cancer before having children.

Many chemotherapy drugs adversely affect fertility and can be toxic to ovaries and testes. Freezing eggs may enable patients who have received or will receive such chemotherapy, for example young women receiving breast cancer treatment, to have children later. Embryos can also undergo genetic evaluation during their creation.

DNA isolated from an embryo can reveal chromosomal abnormalities and mutations. Embryos with more normal genetic structures can be selected for implantation, although the ethics of doing this remain debated.

Some situations usually listed as side effects occur during egg collection. Unwanted effects may include cramps, bloating, fullness, bleeding, infection and excessive egg production, but they are uncommon and mild.

How long can embryos remain frozen? Frozen or fresh embryos?

In theory, embryos can be stored indefinitely at -196 ℃, a temperature where biological processes almost stop. In practice, sufficient time has not elapsed to prove this, since the method was introduced in 1983. Its history is recent. Although pregnancies have succeeded with 10-year-old embryos, further research is needed.

Whether outcomes differ between immediate and later embryo use is under investigation. International Journal of Reproductive Medicine reported a study involving 1000 people whose results showed no difference. Other studies claim the opposite: that frozen embryos are more beneficial for mother and baby and increase pregnancy chances.

We may hear more about embryo freezing in medicine, particularly oncology. Whether frozen embryos will replace fresh ones in the future is debated. More research is needed.

Sperm storage to preserve fertility in male cancer patients

Sperm banking is the best-established fertility-preservation method for men. A sperm bank is a laboratory storing sperm collected from different people. It is a relatively easy and successful way to store sperm for future use. It is generally recommended to young men before cancer treatment, most often before testicular tumor treatment. Importantly, in our country, giving sperm or eggs to couples other than their owners is prohibited. Our country also has no sperm banks storing sperm except in circumstances of disease.

Cancer treatments save increasing numbers of lives every day. However, it is unrealistic to expect such vital treatments to have no side effects. At medicine’s current stage, we have experience managing treatment side effects as well as administering medicines effectively. Managing side effects forms a major part of medical oncologists’ knowledge and experience... Do not hesitate to discuss your illness and concerns with your oncologist. Just as early cancer diagnosis matters, intervening early in side effects and taking measures regarding problems such as infertility are possible and sometimes as vital as treatment itself.