Male Fertility and Cancer Treatment
What is male fertility and how can cancer treatment affect it?
Being able to father a child is known as fertility. Cancer and its treatment can affect a man’s chance of fathering a child. Infertility is being unable to father a child. It is vital to speak openly with your care team about how your cancer and treatment plan could lead to infertility.
A man needs to make healthy sperm to be able to father a child. Sperm grow and mature in the seminiferous tubules, which are in the testicles. A man has two testicles, located in the scrotum. Semen is the fluid that sperm live in. Sperm is always being made, making them a target for chemotherapy damage. Before puberty, there is no sperm being made. Germ cells (where sperm cells come from) are still there and reproducing, making them a target of chemotherapy as well. Germ cells and sperm can also be harmed by radiation, even in low doses.
Another group of cells in the testes are the Leydig cells. The job of these cells is to make the male sex hormone, testosterone. Without testosterone, a boy may not achieve puberty. An adult male with low testosterone may have a loss of secondary sex traits (facial hair, mature genitals, and deep voice) or abnormal sexual functioning. Leydig cells can be harmed by radiation but are not as sensitive to it as sperm and germ cells. Leydig cells are not often harmed by chemotherapy. Having azoospermia (lack of sperm in the semen) due to damage to the germ cells does not affect sexual function but will affect fertility.
The pituitary gland, found in the brain, makes hormones (LH and FSH). These help the testes make sperm and testosterone. Radiation therapy to the brain can damage the pituitary gland, affecting sperm and testosterone production.
Cancer itself can cause men to have poor sperm quality, even before treatment. It is not uncommon for men with Hodgkin's disease or testicular cancer to have low sperm counts at the time of diagnosis. Fortunately, advances in fertility preservation (discussed in Fertility Preservation for Men) have allowed men with poor sperm to father children after treatment.
Chemotherapy and Fertility
Chemotherapy works by killing quickly dividing cells. These can be cancer cells or normal cells. Many cells in our bodies are quickly dividing, like those lining the gut, hair follicles, and germ cells (including sperm and oocytes or eggs). When these cells are damaged by chemotherapy, it causes side effects. These include diarrhea, mouth sores, hair loss, and the inability to have children.
It is very hard to figure out which men will become infertile as a result of chemotherapy treatments. The effects depend on the type and number of chemotherapy drugs received, as well as the total dose. The group of chemotherapies called alkylating agents are known to affect sperm being made, but this depends on the dose. Other chemotherapies that greatly affect sperm being made are chlorambucil and cyclophosphamide when given alone and procarbazine and cisplatin in high doses, among others. In some cases, regimens may be changed to protect a man’s fertility.
Azoospermia (no sperm) or oligospermia (low sperm count) may not be permanent. It can take from months to years for sperm production to improve. Sperm counts are often lower after chemotherapy. There can also be damage to the genetic makeup (DNA) of sperm after chemotherapy. Research has found that this damage is repaired after therapy is done, though it isn’t clear how long this takes.
Each situation is unique. You should speak openly with your care team about the chemotherapy you are getting and how it could change your fertility. Ask your care team how long you should wait after your chemotherapy is done before fathering a child. The effect on fertility is not yet known for many newer types of chemotherapy and other cancer therapies, such as targeted and immune therapies.
Radiation Therapy and Fertility
Radiation therapy is the use of high-energy x-rays to kill cancer cells and can affect your fertility. Radiation to the testicles, or body parts near the testicles, can damage the cells that make sperm. The chance of infertility after radiation depends on the dose to the testes, shielding, and fractionation (single dose vs. multiple doses). Smaller doses can lead to a temporary inability to make sperm. Higher doses can lead to permanent infertility. Leydig cells are less sensitive to the effects of radiation, but damage can still happen.
There are two ways to try to prevent fertility issues from radiation treatment. If the testicles are not the target, shielding can be used. This protects the testicle(s) from being exposed to radiation. Fractionation divides the total dose of radiation into many smaller doses. Fractionation is used to lessen most side effects. In the case of fertility, fractionation (many smaller doses) causes more damage to sperm than a larger, single radiation dose.
Total body irradiation (TBI) is used before stem cell and bone marrow transplants. As the name suggests, it is radiation of the whole body. About 80% of men who have TBI will have permanent azoospermia. Shielding is not a choice in this type of radiation.
For those with temporary azoospermia after radiation, sperm counts are at their lowest 4-6 months after treatment. Counts often return to their pretreatment levels 10-24 months after treatment. This can take longer in those who got higher doses of radiation.
Surgery and Fertility
If a cancer surgery requires the removal of both testes, fertility is affected because the body cannot make sperm. Surgery on the prostate, bladder, urethra, or colon can result in a condition called retrograde ejaculation. In normal ejaculation, the semen is sent through the urethra (the same tube that carries urine from the bladder), and the opening to the bladder closes off, letting the semen leave the penis. In retrograde ejaculation, the opening to the bladder does not close, allowing the semen to enter the bladder instead of exiting the penis. While this is not harmful, it does impair fertility. Sperm can be retrieved from urine collected after ejaculation and used to fertilize an egg.
If a man still makes sperm, is there any danger or risk in fathering a child after therapy?
A common concern is if a child will have birth defects caused by exposure of sperm to cancer therapies. Studies have found no increase in birth defects in the children of cancer survivors. Nor do these children have higher rates of cancer (this does not include families with genetic cancer syndromes).
The DNA of sperm can be damaged by cancer therapies, but this damage repairs itself. You should speak with your care team before fathering a child after treatment for cancer.
It can be difficult, but it is important to speak openly with your care team about your fertility. You can also ask to be referred to a fertility specialist. You can also learn more about fertility preservation options and find links to resources for more information.
The National Infertility Association(RESOLVE) has a lot of helpful information regarding infertility and family building options.
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Nieman CL, Kazer R, Brannigan RE, et al: Cancer survivors and infertility: a review of a new problem and novel answers. Journal of Supportive Oncology 4:171-8, 2006
The Oncofertility Consortium. Found at: http://oncofertility.northwestern.edu/for-patients
Save My Fertility. Found at: http://www.savemyfertility.org/pocket-guides/providers/fertility-preservation-men-diagnosed-cancer
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