Fertility for Cancer Patients
A diagnosis of cancer presents many decisions that must be made quickly. Confirming the diagnosis and planning therapy will be the primary concerns, but the implications of therapy on long-term quality of life must be assessed. One of the primary issues facing women with a diagnosis of cancer is future fertility.
Cancer treatment can interfere with future fertility. Toxicity varies by treatment. Cyclophosphamide, an alkylating agent used in many chemotherapy regimens, is highly toxic to sperm and eggs; methotrexate and 5-flouro-uracil (5FU) are not. Medications used for longer time intervals create a higher risk of fertility problems than shorter time intervals; effects on women in older age groups are more severe than younger. Radiation therapy, in high doses, can have effects on eggs and sperm. Surgery and anesthesia are not known to have direct effects.
It is difficult to give specific fertility risks for chemotherapeutic regimens, since studies are not yet definitive. Among the more toxic treatments are stem cell transplantation for leukemia in which total body irradiation and cyclophosphamide are used, beam radiation to a field that includes the ovaries, and extended chemotherapy of up to 6 cycles using cyclophosphamide in combination with other agents. After conventional chemotherapy for breast cancer for women under 40, the chance of infertility is roughly 50%, in older women the risk is over 80%.
What are the options for fertility in patients diagnosed with cancer? The best choices are available to those that have not yet initiated treatment and involve cryopreservation. During treatment, the risk of problems rises, and after treatment, there may not be adequate recovery of fertility to achieve pregnancy.
Cryopreservation allows cells to be stored with great stability for long periods of time. The record time from sperm cryopreservation to pregnancy is 28 years; there probably is no real limit to the time that cells can be stored. To store cells requires technology that reduces the formation of ice crystals, which disrupt cells, and prevents the rapid rise in salt concentration that occurs as water freezes. Cryopreservatives and management of temperature changes (slow freeze or vitrification) are used to reduce the risk of these problems.
The option for fertility preservation in men is straightforward, cryopreservation of sperm. Sperm is obtained by masturbation and frozen in multiple vials in liquid nitrogen. 2-3 sperm samples can be obtained per week, with 2-4 vials stored per ejaculate; two weeks worth of donations could yield 8-24 vials of sperm. Costs vary widely, but would range from $1500-$3000 for processing and 3 years of storage.
Testicular sperm extraction is an option for individuals with azoospermia. Testicular tissue cryopreservation remains a theory that has not yet produced a human pregnancy. It has been proposed as an option for preservation of fertility in children, but has yet to be proven in clinical practice.
Women have the option of cryopreservation of oocytes or embryos. For women without a partner, oocyte cryopreservation also known as egg freezing holds promise as a means to preserve fertility potential without committing to a specific sperm source or partner. For women with a partner or sperm donor, embryo cryopreservation is a proven technology.
To create cryopreserved oocytes, Follicle Stimulating Hormone (FSH) is administered over a ten day time period to stimulate ovarian follicles. The oocytes are retrieved under sedation with a needle guided by ultrasound and then stored in liquid nitrogen.
Newer techniques of oocyte vitrification secure good pregnancy rates for those with good oocyte quality. Traditional oocyte cryopreservation is performed using a slow freeze technique, but more rapid vitrification procedures optimize results. The trick with cryopreservation is to lower the temperature while avoiding ice crystals that disrupt cell membranes and proteins. Vitrification, an ultrarapid freezing process utilizing a minimal fluid volume, reduces the risk of these problems and optimizes cell quality.
For those women with a partner, or that are willing to commit to a specific sperm donor, embryo cryopreservation is an excellent option. After stimulation and retrieval, oocytes are inseminated and cultured in an incubator for 1-5 days, followed by cryopreservation. The embryos can be thawed and transferred at a later date, after clearance from the oncologist. Embryo cryopreservation is the best established of the fertility preservation techniques, with years of experience in its applications. Good pregnancy rates can be anticipated.
Ovarian tissue cryopreservation, the cryopreservation of whole pieces of the ovary, as opposed to cells, remains experimental. Complex tissues are more difficult to cryopreserve than cells, though rare success has been reported.
Is there risk to the use of fertility drugs in patients with cancer? It does not appear in studies to date that breast or ovarian cancer risk is affected by use of fertility drugs. Studies indicating an increased risk are balanced by other studies indicating a reduction in risk. Studies to date have been limited, and treatment decisions still must be individualized.
Does pregnancy increase the risk of cancer recurrence? In theory, certain types of cancer could be aggravated by the hormones of pregnancy, but studies have not confirmed an overall risk. Certain types of cancer are less common in women that have delivered a pregnancy. Treatment decisions must be individualized, as future studies gather more information.
Certain cancer treatments create organ toxicity that must be evaluated in considering patients for pregnancy. Heart output is limited in patients that have received doxorubicin. Uterine irradiation is associated with miscarriage and pre-term labor.
Children born after fertility preservation procedures do not carry any increased risk for birth defects. There are hereditary syndromes that can be associated with cancer that could be transmitted to children, but there does not appear to be any other increased risk for cancer or genetic disease in children of cancer survivors.
Patients contemplating conception must consider life span expectations as part of their decision on whether to conceive. Such considerations are not, however, a reason to withhold treatment, and are ultimately the individual and family should decide.
Philip E. Chenette, MD
www.livestrong.org Lance Armstrong Foundation
www.cryobank.com California Cryobank
www.PacificFertilityCenter.com Pacific Fertility Center