FERTILITY PRESERVATION IN CHILDHOOD CANCERS:
Diagnosis of cancer in children is devastating for both children and their families. Currently excellent survival rates for paediatric and adolescent cancers makes fertility preservation an important component of long term quality of life. Fertility Preservation options differ in the pre and post-pubertal child Read More
Treatment options available for the Female Child
A. EGG (oocyte) FREEZING
Egg freezing involves harvesting and freezing of unfertilised eggs from the ovary. The patient undergoes a cycle similar to in vitro fertilization (IVF). The process begins with ovarian stimulation using hormones for about 10 days to harvest multiple mature eggs. Next, transvaginal (or, in some cases trans-abdominal) egg retrieval is performed under anaesthesia. The unfertilized eggs are then frozen for future use.
When ready to attempt pregnancy, the frozen eggs are thawed and fertilized. The resulting embryos are transferred to the uterus of the patient or a surrogate/gestational carrier in case the uterus of the patient is compromised. Egg freezing is no longer considered experimental according to the American Society for Reproductive Medicine. Success rates in young women closely follow those seen with embryo freezing with no increase in the congenital malformation rate. The success of the procedure is directly related to the age of the patient when she froze her eggs and number of mature eggs frozen.
B. EMBRYO FREEZING
Embryo freezing involves the freezing and storing of embryos obtained by ovarian stimulation as a part of IVF process, egg retrieval followed by its fertilisation in vitro in the lab with sperm from partner/donor, and then freezing of embryos for later implantation. This process begins with ovarian stimulation using hormones that are self-injected daily by the patient for about 10 days to harvest multiple mature eggs, followed by a transvaginal retrieval of the eggs under anaesthesia. Sperm used to achieve fertilization can be from a partner or donor.
Note: Ovarian stimulation to cryopreserve eggs or embryos can be started at any time of the menstrual cycle avoiding long delays in treatment.
When ready to attempt pregnancy, the frozen embryos are thawed and transferred to the uterus of the patient or, in some cases, a surrogate/gestational carrier in case the patient uterus is compromised. Embryo freezing is a highly successful technique that has been in use for more than 25 years. Live Birth rates for frozen embryo cycles range from 35-45% for women under 35.
POTENTIAL RISKS/CONCERNS WITH OVARIAN STIMULATION1. There is a risk with the use of injectable hormones for ovarian stimulation that they can lead to ovarian enlargement and hyper stimulation (OHSS).
2. The need to delay the start of chemotherapy to allow for controlled ovarian stimulation of the ovaries. However, protocols can be used where stimulation begins in the luteal (second half) of the menstrual cycle and may provide a more flexible schedule for the utilization of hormonal stimulation
3. Cost of treatment can also be a potential barrier.
C. OVARIAN SUPPRESSION (GnRH agonists)Ovarian suppression involves the use of GnRH agonists (e.g, leuprolide, goserelin) to decrease the effect of chemotherapy on the depletion of follicles appears to be a promising option in some cancers like breast cancer. GnRH agonist is administered by injections either monthly or every three months. It should be started around two to four weeks before the first chemotherapy treatment and continued throughout the duration of treatment. Recently, the POEMS trial in Triple negative breast cancer patients demonstrated a significant reduction in ovarian failure and also a significantly increased odds ratio for pregnancy.
SUCCESS RATESOvarian suppression is an upcoming new procedure. It has been studied primarily in women with breast cancer and lymphoma and results evaluating effectiveness in preserving fertility are conflicting and the retention of ovarian function is not guaranteed.
POTENTIAL RISKS/CONCERNSThis procedure can cause menopausal like symptoms, which may be intolerable for some patients; add-back therapy may alleviate some of these symptoms. Additionally, it can also decrease bone density but this is largely reversible.
D. OVARIAN TISSUE FREEZING
Ovarian tissue freezing is currently an experimental technique as per ASRM guidelines however it is extensively used in Europe and Japan. It involves surgically removing all or a part of the cortex of the ovary, which contains thousands of resting primordial follicles. Read More
1. Experimental procedure to be done in an IRB protocol setting.2. This is an invasive surgical procedure requiring anaesthesia.3. Potential to re-introduce cancerous cells, particularly in hematologic malignancies
E. PROTECTION OF OVARIAN FUNCTION/OVARIAN TRANSPOSITION
Ovarian transposition refers to a surgical repositioning of the ovaries outside the pelvic radiation treatment (RT) field to reduce ovarian exposure. Ovarian transposition is generally performed using a minimally invasive surgical procedure. Metal staples are placed around the ovaries in their new locations in order to assist treatment providers visualizing the ovaries, to avoid including them in the RT fields. This procedure should be performed before RT simulation.
The retention of ovarian function using ovarian transposition is not guaranteed and patients should be offered egg or embryo freezing before treatment if there are no medical contraindications. If the fallopian tubes are resected, the patient will not be able to conceive naturally. Instead the patient would need to undergo ovarian stimulation and trans-abdominal egg retrieval. Alternatively, ovaries may be re-positioned after finishing RT in order to place them back into the pelvis.If the uterus is exposed to a high dose of radiation during treatment, the patient may not be able to carry a pregnancy herself and may have to use a gestational carrier.Ovarian transposition will not protect the ovaries from the effects of systemic chemotherapy.
This procedure carries risks for complications from anaesthesia and typical risks associated with any invasive procedure, including bleeding and infection.