Male Fertility and Cancer Treatment

This article is useful for people who were born with a penis and testicles.

What is male fertility and how can cancer treatment affect it?

Being able to father a child is male fertility. If you are infertile, you cannot father a child. Cancer and its treatment can affect your ability to father a child.

It is important to talk with your care team about how your cancer and treatment plan could lead to infertility before treatment begins and when new treatments are started. There are a few ways that cancer treatment can affect your fertility:

• A man needs to make healthy sperm to father a child. Sperm grows and matures 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. This makes them a target for chemotherapy damage. Before puberty, sperm isn't made. Germ cells (where sperm cells come from) are 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.  Having azoospermia (no sperm in the semen) due to damage to the germ cells does not affect sexual function but will affect fertility.
• Another group of cells in the testes are the Leydig cells. These cells make the male sex hormone testosterone. 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.
• 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. It is not uncommon for men with Hodgkin's disease or  testicular cancer  to have low sperm counts (oligospermia) at the time of diagnosis. Advances in fertility preservation (see Fertility Preservation for Men) have allowed men to father children after diagnosis and 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 hard to know which men will become infertile because of chemotherapy treatments. The effects depend on the type and number of chemotherapy drugs received and 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, your treatment plan may be changed to protect 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, though it isn’t clear how long this takes. 

Each situation is unique. Talk with your care team about the chemotherapy you are getting and how it could impact 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 uses high-energy X-rays to kill cancer cells. This 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, the shielding that is used, and fractionation (single dose vs. many doses). Smaller doses can have a temporary effect on your fertility. 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:

• Shielding 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 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 have higher doses of radiation.

Surgery and Fertility

If surgery for cancer removes both testes, fertility is affected because the body cannot make sperm. Surgery on the prostate, bladder, urethra, or colon can cause retrograde ejaculation. In normal ejaculation, the semen goes 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. This allows the semen to enter the bladder instead of exiting the penis. This is not harmful, but it does impair fertility. Sperm can be retrieved from urine collected after ejaculation and used to fertilize an egg.

Is there any danger or risk in fathering a child after therapy?

A common concern is the risk of birth defects caused by sperm exposure to cancer therapies. Studies have found no increase in birth defects in the children of cancer survivors. These children do not 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 in time. Talk with your care team before fathering a child after cancer treatment.

It can be hard, but it is  important  to speak up about your fertility.  You can also ask to be referred to a fertility specialist. Learn more about fertility preservation options  and find links to resources  for more information.