Cryopreservation at Mayo Clinic protects children with cancer from infertility
- 04 September
- Diagnosis & Treatment
Egg cryopreservation, which is widely used by Mayo Clinic specialists in the US, protects children with cancer from infertility – the devastating late effect of chemo and radiotherapy.
Cancer treatments affect the reproductive system of boys and girls.
Side effects can be short-term and reversible, but cell damage and scarring can turn into permanent problems in distant future.
Infertility as a late effect of cancer treatment in America is recognized as one of the most serious problems of pediatric oncology. Achievements in this area have significantly increased the survival rate of young patients. But now thousands of cancer survivors face a new problem: the risk of infertility and congenital abnormalities in future generations.
Mayo Clinic in Rochester (Minnesota) uses one of the newest procedures recommended by the American Society of Clinical Oncology – cryopreservation of reproductive cells.
According to Dr. Zaraq Khan, cancer diagnosis is shock for every parent.
When a child is in danger, the reproductive consequences of therapy are often overlooked. Mayo researcher notes that cancer treatment as a whole has made significant progress, but the issue of maintaining fertility remains unresolved.
Dr. Khan is engaged in reproductive endocrinology researches at Mayo Clinic. His team helps children and adults protect themselves from the late effects of cancer therapy, keeping the healthy egg frozen for years. American oncologists try not only to save little patients, but also to prevent long-term consequences of toxic therapy.
Gamete cryopreservation (freezing of reproductive cells) is a real opportunity to preserve fertility after aggressive chemotherapy or radiotherapy. After remission, thawed cells can be returned back to the patient's body restoring reproductive potential. Numerous clinical trials and observations show that innovative option is completely safe.
How cancer treatment affects fertilityChemotherapy and radiotherapy can destroy the genetic material of cells. This is the principle of antitumor activity. But toxic agents don’t make the difference between malignant cells and healthy cells.
The entire body of the child suffers from toxic therapy.
Girls are born with a certain number of eggs. They cannot be replaced or restored.
If the eggs are exposed to powerful mutagenic factors in childhood, the reproductive consequences may be irreversible. Therefore, the best prevention is the preservation of cells during treatment.
Cancer treatment affects fertility in different ways.
ChemotherapyReproductive effects most often occur after treatment with alkylating agents. Procarbazine, ifosfamide, cyclophosphamide, busulfan, melphalan – all these drugs associated with infertility. High doses of alkylating antineoplastic agents cause irreversible damage to the genetic material of the egg, so oncologists use them in minimal doses. But nothing is 100% safety, especially chemo.
Such agents as vincristine cause reversible short-term disturbances of the menstrual cycle in young girls. However, vincristine and methotrexate do not cause ovarian depletion and early menopause.
RadiotherapyRadiation is extremely dangerous for the ovaries and testes at any age. Irradiation of the abdominal cavity, pelvis, spine, as well as total body irradiation brings the maximum risk for fertility. Cranial irradiation disrupt neurohormonal signals that control reproductive system functioning. Complications sometimes require hormone replacement therapy or more complex treatment.
Ovarian failure (a pathological decrease in ovarian function) can be the result of pediatric cancer radiotherapy. Delayed puberty, irregular menstruation, impaired fertility, severe complications of pregnancy due to scarring of the uterus – the effects of radiation are detrimental.
Boys also suffer from long-term reproductive and hormonal effects after radiotherapy.
Cancer surgeryToday, surgery is a “gold standard” of treatment for most types of solid tumors. If the child is diagnosed with brain or kidney cancer – most likely, he will be recommended for surgery.
But surgery sometimes affects the reproductive system, leaving inflammation, scar tissues, accidental nerve damage and other unpleasant consequences.
How to protect children with cancer from infertilityTo prevent late reproductive consequences of chemotherapy and radiotherapy, Mayo Clinic doctors recommend cryopreservation of testicular tissue or sperm (for boys), as well as freezing of ovarian tissue or oocytes (for girls).
These options correspond are also recommended by ASCO.
Cryopreservation in girls⦁ Freezing ovarian tissue. This option involves laparoscopic removal of the immature ovaries followed by cryopreservation. When the cancer is defeated, your child undergoes second surgery – ovarian transplantation. The approach is technically complex, and some doctors fear that the ovarian tissue may contain "dormant" malignant cells.
This is a real danger.
⦁ Freezing oocytes. If young girl entered puberty (usually 10-15 years), doctors can preserve unfertilized eggs after two weeks of hormonal therapy. Unfortunately, sometimes the patient cannot wait with cancer treatment for two weeks. In addition, this approach is not suitable for little girls.
Cryopreservation in boys⦁ Testicular tissue freezing. If little patient has not reached puberty (before 12 years of age), cryopreservation of testicular tissue can preserve reproductive function. This is a new experimental approach, which involves the removal of sperm-producing tissue. After cancer remission, surgeons return these cells back to the testicle or use stem cells that can later produce sperm.
⦁ Sperm cryopreservation. After 13 boy's testicles produce functional sperm, which can be stored in special lab for future IVF procedures. Unlike experimental manipulations with testicular tissue, this is a simple and well-established technique that is widely used across the United States.
Mayo Clinic do everything possible to prevent complications of cancer treatment in your child.
© Analytical reviews and oncology news by K. Mokanov: clinical pharmacist and professional medical translator