Research in fertility options
Fertility problems may occur after certain cancer treatments, such as surgery, chemotherapy or radiation therapy. Sperm or egg banking (freezing) and banking embryos are proven options for people who wish to have children after cancer treatment that could affect fertility. Researchers are studying other ways that may help preserve a person’s fertility, but these are still considered experimental. Find out more about fertility problems from cancer treatment and fertility options currently available.
Although the techniques described below show some promise, more research is needed to find out how effective they are and if they have long-term effects for the children born when these techniques are used. There are concerns that some of the experimental techniques could reintroduce cancer cells, but the chances of this happening are not fully known.
Preserving a person’s fertility may involve one or more procedures such as banking or freezing unfertilized eggs or sperm, in vitro fertilization (IVF) and implantation of a fertilized embryo. There is a cost associated with each of the procedures. Some fertility options may not be covered by medical insurance. It is important for people considering fertility-preserving options to discuss the costs of these procedures with their doctor or fertility clinic.
Research in fertility options for women
Researchers are looking into the following fertility options for women. These experimental fertility options may not be available to all women in Canada.
Freezing ovarian tissue
The entire ovary, or part of ovarian tissue containing immature eggs, is removed and frozen. If the entire ovary is removed, it is sectioned into thin strips of tissue and frozen. The ovarian tissue is kept frozen and is only returned to the woman’s body if treatment is successful and a woman wishes to try to restore ovarian function.
The ovarian tissue is usually implanted close to a Fallopian tube. Doctors have also transplanted the tissue in other places in the body, such as the abdomen, breast or arm. This allows easier access to remove eggs. These may also be the best places for transplantation in women who have a high risk of cancer recurrence or whose pelvis has scarring from radiation therapy. Once the eggs mature, they can be collected and fertilized in the lab (in vitro) and then later implanted in the woman’s uterus or the uterus of another woman, called a surrogate.
The transplanted ovarian tissue usually survives for only a short period of time (a few months to a few years). For this reason, tissue is not usually transplanted until a woman is ready to become pregnant. This technique is in the early stages of development. Only a few live births have been reported using this procedure. Recently, doctors have used a fast-freezing technique called vitrification, which seems to help prevent damage to ovarian tissue.
Researchers are studying freezing ovarian tissue as a way to preserve fertility in women who need to begin treatment right away and can’t wait to prepare for egg collection (ovarian stimulation). This method can also be used for women who don’t want to have ovarian stimulation. Women may also wish to choose this option if they prefer to find a male partner and don’t want to use donated sperm. Freezing ovarian tissue is also an option for girls who have not reached puberty and are having a treatment that may affect their fertility.
Using donated embryos
Embryo donation may be an option for some women whose fertility has been affected by cancer treatment but who still want children. Embryo donations usually come from a couple who used assisted reproductive techniques and who have extra frozen embryos. The woman who uses an embryo donation will not be blood-related to the child.
A woman can have in vitro fertilization (IVF) with a donated embryo as long as she has a healthy uterus. Women who use a donated embryo will have to get hormone treatments to prepare the lining of the uterus for IVF. The embryo is thawed and transferred to the woman. The woman will continue hormone treatments until blood work shows that the placenta is working on its own. This is usually around 8–10 weeks after the embryo is implanted.
There hasn’t been a lot of research on the success rates of embryo donation so it’s important that women find out the IVF success rates at the centre where the procedure is done. Research shows that frozen embryo transfers have a lower live birth rate than fresh embryos. Live birth rates are also related to the age and health of the woman who is undergoing IVF. Cancer survivors may be older and less healthy than a surrogate carrier (another woman carries and bears the child for potential parents) who undergoes IVF with a donated embryo. So, the chance of a live birth for a cancer survivor may be lower than for a surrogate carrier.
Researchers are looking into ways of stopping or slowing down the process by which eggs mature and are released.
Gonadotropin-releasing hormone drugs
A gonadotropin is a pituitary hormone that stimulates the growth and function of the gonads (the testicles in males and the ovaries in females). Gonadotropin-releasing hormone agonist (GnRHa) drugs may be given before and every 1–3 months during chemotherapy treatment. These drugs cause a woman to go into temporary menopause, which stops eggs from maturing and being released. These drugs are usually given once a month and are started before chemotherapy or radiation therapy to the pelvis begins. GnRHa drugs are given every month that a woman is having cancer treatment and in the 3 months following the last treatment. Their effectiveness in preventing ovarian failure is unproven.
Both GnRH agonists (GnRHa) and antagonists (GnRHan) prevent the release of hormones that control ovarian function. Some research shows that GnRHa may protect ovarian function and lower the chance of infertility after chemotherapy. Other studies do not show this effect. There is also some evidence that GnRHa may preserve ovarian function in girls who have not reached puberty.
GnRHan drugs are best used with ovarian stimulation and egg retrieval as part of a program of fertility preservation such as freezing eggs (for women without a male partner) or embryos for those with male partners. Researchers have not yet proven that GnRHan drugs used alone are effective in preserving fertility in women. More research is needed.
Some research suggests that oral contraceptives (birth control pills) may be a way to preserve fertility in women undergoing cancer treatment. Some doctors believe oral contraceptives lower activity in the ovary and protect the eggs. Oral contraceptives have not been shown to be very successful in preserving fertility in women undergoing chemotherapy. Girls who have not reached puberty should not be treated with oral contraceptives because their ovaries are already considered to be in a “resting” state.
Oral contraceptives are not recommended for women with hormone-dependant cancers such as breast cancer. Women should also be aware that cancer and its treatment may carry a risk of blood clots and that oral contraceptives also carry this risk.
Hysterectomy is sometimes used to treat women with early stage endometrial cancer (a type of uterine cancer). Researchers are studying other treatment options for women of child-bearing age who would like to preserve their fertility. Progestin therapy may be an option for some of these women.
Progestin therapy is an experimental cancer treatment that uses the hormone progesterone. Progestin therapy can be given by mouth (oral progesterone) or an intrauterine device (IUD) that releases progestin. It can help shrink a uterine tumour or may even cause it to go away completely.
Women who receive progestin therapy are watched closely for signs that the cancer is not responding to the treatment or growing larger. The risks linked with progestin therapy for uterine cancer are a high rate of recurrence and spread outside of the uterus.
Research in fertility options for men
Researchers are looking into the following fertility options for men. These experimental fertility options may not be available to all men in Canada.
Testicular sperm extraction and percutaneous epididymal sperm aspiration
Testicular sperm extraction (TESE) and percutaneous epididymal sperm aspiration (PESA) are techniques used to collect sperm. TESE is a surgical procedure that removes tiny pieces of tissue from the testicle. PESA is a less invasive procedure. It removes sperm cells from the epididymus (the coiled tube that sits on top of the testicle that stores sperm before ejaculation) using a very thin needle (called fine needle aspiration).
The tissue or fluid removed during TESE or PESE is examined for sperm cells. Any sperm cells found can be used right away for IVF or they can be frozen for future use.
These techniques have been tried in men who don’t have cancer but who have very low sperm counts or no sperm in their semen (azoospermia). Researchers are also studying TESE and PESA in boys and men before they start cancer treatments like chemotherapy.
Men with prostate or bladder cancer may have had surgery to remove the prostate gland and seminal vesicles. These organs make most of the fluid in semen. The vas deferens (tubes that connect the testicles to the prostate) are also usually cut during surgery for these types of cancer. In these men, there is no way for sperm to leave the body and there is no semen. These men may choose TESE or PESA as a way to collect sperm.
Freezing testicular tissue
Researchers are studying the effectiveness of freezing testicular tissue in boys who haven’t reached puberty. Testicular tissue, including the cells that make sperm, may be removed by surgery, frozen and stored. After cancer treatment, the tissue may be transplanted back into one or both testicles, or immature sperm cells from the removed tissue can be injected into one or both testicles. No live births have yet been reported with this method.
GnRH agonists and antagonists, steroids and anti-androgens may put the testicles into a “resting” state similar to the time before puberty (pre-puberty). Some doctors think these drugs may protect testicular function and lower the chance of infertility after chemotherapy or radiation therapy. More research that includes long-term follow-up is needed before GnRH drugs can be recommended to preserve a man’s fertility.
Retroperitoneal lymph node dissection (RPLND) is sometimes done to treat testicular cancer. It is surgery to remove lymph nodes from the back of the abdomen behind the abdominal cavity (called the retroperitoneum) that are around the large blood vessels called the aorta and inferior vena cava. Sometimes the nerves that control ejaculation are damaged during RPLND. Damage to these nerves can lead to no ejaculation or retrograde ejaculation where semen goes into the bladder instead of the urethra and out the end of the penis.
Doctors are studying electroejaculation as a way to collect sperm for IVF in men with ejaculation problems. Electroejaculation involves using a rectal probe to stimulate the prostate gland and seminal vesicles. Since retrograde ejaculation may occur, a catheter is also put into the bladder to collect sperm. Electroejaculation is done under general anesthesia (you will be unconscious).