Techniques to Preserve Fertility

Currently, fertility preservation treatment counts on advanced assisted reproduction techniques, giving the patient enough time to start chemotherapeutic or radiotherapeutic procedures. For women, the procedure can be performed between 10 and 15 days before the beginning of the oncological therapy, at any phase of the cycle, without her having to wait for her next period. It is worth noting that it is not necessary to delay treatment because of the menstrual cycle.

For most men, on the other hand, treatment is much simpler and in up to five days, 02 to 03 semen samples can be collected and stored, enabling excellent reproductive stock.

The technique of choice will depend on the patient’s age, time available for all actions to be taken without interfering with the oncological therapy, and type of cancer. This choice must be made together with the oncologist, in due time, without harm to the patient’s health.

Find below the techniques to preserve fertility:

  • Semen Cryopreservation: a widely used and consolidated technique because it is part of the laboratory’s routine to preserve sperms. Sperms are cells that respond well to freezing and thawing, with very high survival rates.

There is no time limit for freezing; there are reported cases of children born with semen frozen for over 20 years. Ideally men collect their semen through masturbation in the lab on different days, for a total of three seminal samples for storage, with no need of any special preparation by the patient. If there is no time before the beginning of the chemotherapy, at least one sample should be collected.

  • Embryonic Cryopreservation: one of the most common and consolidated ways to preserve the patient’s or the couple’s capacity of conceiving in the future. Before freezing the embryos, the patient must go through an In Vitro Fertilization (IVF) procedure, known as Emergency IVF, since it is quick and with no need to wait for the menstrual period.

Before the collection of oocytes, embryos are produced from the union of the oocyte and the sperm in lab; therefore, for this technique the patient must have a partner. Morphologically viable embryos are cryopreserved on the second or third day of extracorporeal life, or alternatively on the fifth day at the blastocyst stage. Therefore, once the cancer treatment is completed and if the patient decides to have children, it is possible to transfer the embryos to the womb after an ovulation cycle with the help of a hormonal preparation of the endometrium imitating an ovulatory cycle.

Embryonic survival rates to the freezing and thawing process are high and with the enhancement of vitrification techniques they can be of more than 80%.

  • Oocytes Cryopreservation: technique used worldwide in which, before it begins, the patient goes through an ovulation induction period with the purpose of follicular growth and selection, followed by aspiration and microscopic identification of oocytes for vitrification (freezing).

The ovulation induction stage takes place at intervals that range from seven to 14 days, with no need to wait for the period to begin in a way that it is enough to have two weeks available before chemotherapy to conduct the procedure.

In the event of immature oocytes – without the complete ovulation induction stage – they can also be cryopreserved after going through an in vitro maturation process, conducted before or after preservation, making the process even faster.

Oocytes can be cryopreserved for an indefinite term. Currently the thawing survival rates are close to 85% with vitrification techniques.

This procedure is suitable to single women since the sperm fertilization stage does not have to be conducted.

  • Ovarian Tissue Cryopreservation: with this technique a small fragment of ovarian tissue is surgically removed and frozen before the beginning of the cancer therapy. There are several freezing techniques for this procedure and, among those most used, are slow freezing and vitrification. Once the oncological therapy is completed, and depending on the health status and desire of the patient (and the spouse) to get pregnant, thawing of small ovarian fragments for transplant is performed and it can be autotrophic (remaining ovarian implant) or heterotrophic (insertion of ovarian fragments in the subcutaneous line of the arm and abdomen).

After transplant and evidence of the tissue’s health, pregnancy can be spontaneous or, if required, we can still count on the support of IVF techniques. Freezing of ovarian tissue, although already easily performed, is still considered experimental since the number of pregnancies after transplant is still small. Nonetheless, the number of patients making use of the freezing technique is increasing worldwide and research in this area is growing significantly. This procedure is indicated for patients with less than one week to begin chemotherapy and for pre-adolescent children.

  • Testicular Tissue Cryopreservation: through a testicular biopsy, seminiferous tubes are aspired and the spermatogonial stem cells present in the testes are isolated and frozen. This procedure is indicated for children (pre-adolescent) who have not yet entered into puberty, and because of that, have not started the production of sperms (spermatogenesis). This technique enables that after oncological therapy and proved cure of these patients, these cells are transplanted again into the testes or differentiated in vitro, enabling those patients to resume the production of their own sperm and, consecutively, have their own biological children. Currently, this procedure is experimental.
  • Ovarian Function Suppression: there are drugs known as GnRH analogs that are capable of blocking ovarian hormonal production, leaving it “to rest”. Suppressed ovary will not ovulate and its follicles will be somehow protected from chemotherapy drugs, easing the detrimental effect they have on the ovaries. The efficacy of this method is controversial and there is no consensus yet, but it seems that this method can work in young women who will not have enough time before chemotherapy to make use of more sophisticated techniques.
  • Ovarian Transposition: this technique consists of surgically moving the ovaries and attaching them away from the radiation therapy area. The purpose of the surgery is to keep the ovary’s biological functions out of the way of harmful radiation. This technique must be performed before the beginning of radiotherapy and it is important to highlight that it will not protect against the effects of chemotherapy. The ovarian transposition technique is indicated for patients who will receive radiotherapy in the pelvis area.

In all those clinical cases, it is imperative the combined efforts of the oncologist and a specialized human reproduction team to provide the patient with reasonable support to make the most appropriate decisions regarding the oncological therapy and the preservation of fertility.

Fertility Preservation