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Oocyte Cryopreservation

Possible damage to the ovaries is not the only way cancer treatment puts fertility at risk. Some treatments continue for many years, delaying pregnancy during peak years of fertility. For example, about 70 percent of breast cancers are the type treated with drugs like Tamoxifen that block the action of estrogen. These drugs are taken for five to ten years, during which time women are advised to avoid pregnancy. This is another reason many women explore their options for preserving fertility before cancer treatment.

Ovarian stimulation

If you choose to freeze eggs or embryos, you will undergo a process called ovarian stimulation to promote development of multiple eggs for possible freezing.

During the process, which takes about 14 days:

  • You will have regular appointments in the clinic – usually three appointments in the first week, and appointments every other day or daily in the second week
  • You will need to inject medications daily. The medications contain the same hormones the brain sends to the ovaries to tell them to develop a single egg each month.
  • Aided by the hormones, eggs will mature inside sacks filled with fluid called follicles.
  • You will also have regular blood tests and ultrasounds during your appointments. These tests allow your doctor to monitor how the follicles are maturing and adjust the level of hormones you need.

The egg retrieval procedure

Once testing confirms enough well-developed follicles, you will be given another injection of medication to begin ovulation, and you will be scheduled for a minimally-invasive procedure to harvest the eggs.

  • The procedure is very safe, with a complication rate of less than one percent.
  • You will receive sedation, so you will be sleeping, but breathing on your own.
  • During the procedure, a thin, hollow needle is passed through the vagina into the ovaries under ultrasound guidance.
  • The contents of the follicles are drawn out through the needle.
  • The retrieved eggs, along with fluid from the follicles, are sent to the laboratory, which is just a few steps away. There, an embryologist will examine them under a microscope.
  • Before you leave that day, you will know how many eggs were retrieved.
  • Later in the day we will be able to freeze all of the mature, viable eggs and store them on site.

Coordinating with cancer treatment

Michigan Medicine’s Fertility Preservation Program works closely with your oncology team to coordinate ovarian stimulation and egg retrieval with the beginning of your cancer treatment.

For example, if you are diagnosed with breast cancer, your fertility preservation can be accomplished before and/or immediately after breast surgery, but before chemotherapy.

Here is an example of how fertility preservation can be coordinated with your cancer care, either before or immediately after breast surgery, but prior to starting chemotherapy:

    1. The Fertility Preservation Coordinator can often meet with you at the time of your first oncology appointment (or call you that day) and give you a brief overview of your options.

    2. Within days of receiving your diagnosis and discussing your treatment plan with your oncology team, you can be seen in the Reproductive Endocrinology and Infertility Clinic for an assessment and counseling.

    3. If you are a candidate for and choose to pursue fertility preservation, you can begin ovarian stimulation hormones right away.

    4. Breast surgery can be scheduled either before or after your ovarian stimulation.

    5. The egg harvesting procedure can be performed as early as two weeks following breast surgery.

    6. This ensures that the eggs are safely preserved, and you can begin chemotherapy when indicated and you have recovered from breast surgery.

Since it is standard to begin chemotherapy within 28 days of breast surgery, this scenario does not delay cancer treatment. In fact, a second attempt to harvest eggs prior to chemotherapy may be possible. This option is sometimes proposed to assist women who do not generate as many eggs from the first stimulation.

Your Fertility Preservation Coordinator

Both breast cancer treatment and fertility preservation can be intense events. There is much to learn, many decisions to make, and multiple steps and clinic appointments to coordinate. To help ease the stress, we provide a coordinator to assist patients with coordinating fertility preservation with the other components of cancer care. The coordinator can help patients understand fertility preservation options, as well as with appointment scheduling and finding answers to insurance and payment questions.

Egg preservation Options after cancer treatment

Cancer treatments including radiation therapy and chemotherapy can negatively impact a woman’s fertility. Sometimes cancer treatments can cause a woman to enter menopause earlier, which can also diminish her fertility. We offer laboratory analyses to assess a woman’s ovarian reserve and counseling to help her understand her options.

Embryo cryopreservation and testing

A woman who has a partner may choose to cryopreserve fertilized eggs – embryos – instead of unfertilized eggs. The process is similar to that outlined above. Embryos can be tested for specific genetic mutations (called pre-implantation genetic testing for monogenetic disorders, or PGT-M). This may be important for a woman whose cancer resulted from a genetic mutation, such as breast cancers resulting from mutations in the BRCA1 or BRCA2 genes. Embryos can also be tested for issues with the number of chromosomes present, which decrease the chance of pregnancy and increase the risk of miscarriage. This method, called pre-implantation genetic testing-aneuploidy or PGT-A, may be most useful for women over 35 years of age.

Testing for these specific genetic mutations is well-established, having been performed for more than a decade. Women may or may not choose to request these tests, they may or may not choose to learn the results, and they may or may not choose to take a specific action based on the results.

Coordinating fertility preservation with surgeries for women genetically predisposed to cancer

Women who carry high-risk mutations for the development of breast and ovarian cancer may pass that cancer risk to their offspring. These patients may elect to proceed with risk-reduction surgeries before cancer is diagnosed – including breast removal (mastectomy) and ovary removal (oophorectomy).

We take a multidisciplinary approach to caring for these women, bringing together specialists in surgical oncology, reconstructive surgery, reproductive endocrinology and obstetrics and gynecology. The team has successfully treated BRCA-positive patients who wish to pursue both preventive (prophylactic) surgeries and fertility preservation.

Here is an example of the steps in a carefully coordinated treatment plan for a patient with a genetic predisposition to cancer who wishes to reduce her cancer risk and preserve her fertility:

    1. Mastectomy and reconstructive surgery

    2. Fertility preservation to harvest and freeze eggs – in this case, freezing fertilized embryos rather than unfertilized oocytes

    3. Pre-implantation genetic testing to identify the embryos that do not carry the harmful mutation(s) (This type of testing can only be performed on embryos, not oocytes.)

    4. Implantation of a healthy embryo

    5. Pregnancy and childbirth

    6. Oophorectomy surgery (to removal the ovaries) (note that it is not necessary to keep the ovaries to have a healthy pregnancy, i.e. the ovaries can be removed before embryo implantation.

Frequently asked questions about Embryo cryopreservation and testing

Q: Isn’t it true that only embryos can be successfully frozen, not unfertilized eggs?
A: Due to improvements in freezing techniques, a frozen egg is essentially equivalent to a freshly harvested egg, so there is no need to create embryos unless a woman elects to do so.

Q: Don’t you have to schedule egg harvesting with a specific time in a woman’s cycle? If it’s not the right time for me when I’m diagnosed, would I have to delay my cancer treatment?
A: We used to think that was the case, but we now know that the ovaries can prepare eggs continuously, so we can begin ovarian stimulation at any time. This helps minimize any delays to cancer treatment.

Q: Won’t the hormones used in ovarian stimulation lower my chance of surviving breast cancer or increase the risk that my cancer will come back?
A: To date ovarian stimulation has not been shown to impact breast cancer outcomes (or any other cancer).

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