What is Ovarian Tissue Cryopreservation (OTC)?
Many medical conditions, like cancer, require treatment that can impact long term fertility and reproductive health. OTC is a procedure that may allow girls and young women the opportunity to have children later in life by removing and freezing ovarian tissue before these treatments start.
Cryopreserving, or freezing, ovarian tissue requires a surgical procedure, performed in which an ovary or part of an ovary is removed. The tissue containing immature eggs is frozen, and stored for use later in life. This tissue may be re-implanted inside the body, or potentially, the eggs could be matured outside of the body and used later through in vitro fertilization.
Who is involved in the OTC procedure?
A Fertility Preservation/Onco-fertility Physician meets with patient, family, and treatment team to determine fertility risk, identify available preservation options, and coordinate team efforts throughout the treatment process. The team will discuss with the patient & family regarding OTC, performs the procedure, and provides follow up care after surgery.
How is OTC different from other types of fertility preservation?
Embryo and egg freezing are established forms of fertility preservation available to females who have started menstruating
- Freezing eggs requires that young women take a hormonal medication to make many eggs at one time.
- With egg freezing, a male partner later
- Embryo preservation requires an available source of sperm.
- These embryos or eggs are retrieved and frozen for future use
- These processes may require 10 to 14 days to complete.
Ovarian tissue cryopreservation programs are becoming increasingly available.
- only been in existence around the world for approximately 15 years
- there is very little information about the use of this tissue in girls that underwent OTC at a young age.
- However, there have been over 100 pregnancies world-wide to date for women using this tissue in their twenties and thirties.
An OTC procedure takes approximately one hour and may be done as a day-care surgery.
- It also may be combined with other procedures in the operating room to limit the need for additional anesthesia.
- It is generally performed as a minimally invasive surgery (lapascopically).
Who are the appropriate candidates?
Ovarian tissue cryopreservation is usually only considered in certain cases
- Patients who do not have time to undergo controlled ovarian stimulation (COS) for embryo or oocyte cryopreservation.
- COS is the more mature technology and should be the first-line treatment if time allows.
- Patients who are planning surgery for another reason may be good candidates for ovarian tissue cryopreservation.
- Specifically, this may include women planning an ovarian removal as part of their treatment for endometrial cancer, etc.
- Pre-pubertal girls who do not have the option of COS.
OTC is generally not recommended in women who:
- are >41 years old
- have a large ovarian cyst on the ovary to be cryopreserved
- have received prior chemotherapy that has significantly impaired ovarian function
For cancer patients, the general recommendation is to avoid transplantation of ovarian tissue in cases where there is concern about reseeding cancer cells, and instead, to consider in vitro maturation of oocytes.
Pregnancies from OTC?
It is important to emphasize that OTC is experimental and that a very limited number of pregnancies have resulted from this technology. The following table gives a summary of live births after autologous transplantation of cryopreserved-thawed ovarian tissue.
Special Circumstances with OTC
- Turner Syndrome
- One study found that ovarian tissue biopsied from girls with Turner Syndromehad identifiable follicles in 26% of the cases.
- Factors that were associated with an increased likelihood of finding follicles included mosaic karyotype, normal FSH levels, AMH levels above 2 pmol/liter, spontaneous menses, and spontaneous puberty
- It is unknown if follicles identified in these patients will be able to produce viable oocytes.