Ovarian Tissue FreezingMedical editor Peter Ferdorcsak Ph.D.
Oslo University Hospital
Presently, ovarian tissue freezing is still in a trial stage. Optimal indication, clinical efficacy, and technical conditions for freezing tissue are still being explored and changing.
The treatment is authorized by law in the regulation for biotechnology § 2–17 in Norway. The Womens' Clinic at Oslo University Hospital located at Rikshospitalet performs ovarian tissue freezing for Norway.
Thawing and reintroduction of tissue, and possibly in vitro fertilization, are possible techniques for reestablishing fertility after full remission of cancer. On a world basis, only a minority of births have been documented after reintroduction of ovarian tissue. Until now, it has not been relevant to reintroduce ovarian tissue for women in Norway who have stored tissue at Oslo University Hospital. Due to the experimental nature of the method, the patient must be well informed of the uncertainty surrounding the technique and the need for further method development.
The indication for ovarian tissue freezing is gonadotoxic treatment including chemotherapy and radiation therapy which lead to a high probability (> 50%) of sterility. The treating oncologist makes the final decision for the procedure.
Ovarian tissue freezing provides women who are treated for cancer the possibility of maintaining their fertility.
Examples of diagnoses where ovarian tissue freezing may be relevant:
- Cancer in pediatric and adolescent years:
- Cancer in women of reproductive age:
- breast cancer
- Benign hematological diseases, for example thalassemia or major aplastic anemia. Freezing of ovarian tissue is rarely indicated in other benign diseases.
Theoretically, there is no lower age limit for removing ovarian tissue, but an individual assessment must be done in each case.
- Age > 35 years
- HIV infection, hepatitis B, hepatitis C or syphilis
- Conditions which exclude a laparoscopic ovariectomy
- Treatment which prevents future pregnancy such as a hysterectomy or life-long treatment where pregnancy is contraindicated.
- Ovarial reserve is already lost due to, for example, previous chemotherapy or induction treatment. Previously completed chemotherapy with preserved ovarial reserve is not a contraindication.
- Disseminated systemic cancer is a relative contraindication. Risk of micrometastases in frozen tissue makes reintroduction of tissue in these cases inappropriate. In vitro fertilization of egg cells is a technique apparently several years into the future. These patients should therefore be well under 35 years.
- Maintain fertility in females £ 35 years undergoing treatment that will eradicate or strongly reduce fertility.
Radiation and chemotherapy are gonadotoxic which can lead to ovarian failure and infertility by inducing apoptosis and/or DNA damage in egg cells and surrounding cells.
Depending on the type of cancer and regimen for chemotherapy and radiation therapy, the treatment can lead to ovarian failure and infertility. The age of the female is significant. Young girls and women maintain menstruation and reproduction ability to a larger degree than women over 30 years, however they also become menopausal earlier than expected.
Oncologist at the treating institution
- Consider oncological indications and contraindications regarding the procedure
- Inform the patient about the option
- Contact the department for childlessness and assisted fertilization
Physician at the department for childlessness and assisted fertilization
Assess the patients situation according to the requirements of the biotechnology laws and regulations, surgical risk, ovarian reserve, and planned treatment course.
- Obtain written consent for freezing of tissue.
- Decide the day for the operation.
- The procedure is carried out under general anesthesia.
- An entire ovary or biopsies from the ovaries are retrieved by laparoscopy.
- After preparation in the laboratory, the tissue is frozen and stored at -196 °C.
Storage of preserved ovarian tissue
The preserved ovarian tissue can only be stored as long as it is required by the donor and as long as it is considered medically justifiable after individual assessment. The tissue should be destroyed when the woman dies.
The option to freeze and store ovarian tissue does not provide an automatic right for future reintroduction of tissue or other form of treatment. The decision is made by the treating doctor according to guidelines set by biotechnology laws and other relevant regulations.