How does cancer treatment affect fertility in men

A lot of things must take place for a couple to make a baby, and a “system malfunction” at any point can lead to infertility. Cancer, or more often some cancer treatments, can interfere with some part of the process at almost any stage and affect your ability to have children.

Chemotherapy

During puberty (usually around age 13 to 14), a boy’s testicles start making sperm, and they normally will keep doing so for the rest of his life. Since sperm cells divide quickly, they are an easy target for damage by chemotherapy (chemo). The higher the dose of chemo, the longer it takes for sperm production to get back to normal, and the more likely it is to stop. Permanent infertility results if all the stem cells in the testicles are damaged to the point that they can no longer produce maturing sperm cells. The most damage is done when men are treated with both chemo and radiation therapy to the abdomen (belly) or pelvis.

The risk of the chemo causing infertility varies depending on the type of drug and the doses used. After chemo treatment, sperm production slows down or may stop altogether. Some sperm production usually returns in 1 to 4 years, but can take up to 10 years. If sperm production has not recovered within 4 years, it’s less likely to ever recover. Men older than 40 may also be less likely to recover their fertility, but age seems to be a less important factor for men than for women.

Chemotherapy drugs that are linked to the highest risk of infertility in men include:

• Chlorambucil (Leukeran^®)
• Cyclophosphamide (Cytoxan^®)
• Procarbazine
• Melphalan (Alkeran^®)
• Cisplatin
• Nitrogen mustard
• Actinomycin D

Higher doses of these drugs are more likely to cause permanent infertility, and sometimes other drugs that are given along with these can increase their effect. For example:

• Busulfan given with cyclophosphamide increases the chance of lifelong infertility more than cyclophosphamide alone.
• Ifosfamide given along with cisplatin can raise the infertility risk higher than cisplatin alone.

Other chemo drugs can also cause lifelong or short-term infertility. For instance, carmustine (BCNU) and lomustine (CCNU) can cause prolonged infertility when given to boys before puberty, and it’s thought they can do the same in men.

Some of the drug combinations used to treat lymphoma, osteosarcoma, and leukemia can cause prolonged infertility in up to half of the men who are treated. For some of these illnesses, there are drug combinations that are less likely to harm fertility, so be sure to talk with your doctor about the treatment recommended for you.

Some drugs such as those listed here have a low risk of causing infertility in men, as long as they are given in low to moderate doses:

• Doxorubicin (Adriamycin^®)
• Carboplatin
• Thiotepa
• Cytosine arabinoside (Cytosar^®)
• Vincristine (Oncovin^®)
• Vinblastine (Velban^®)
• Bleomycin
• Dacarbazine
• Daunorubicin (Daunomycin^®)
• Epirubicin
• Etoposide (VP-16)
• Fludarabine
• 5-fluorouracil (5-FU)
• 6-Mercaptopurine (6-MP)
• Methotrexate
• Mitoxantrone
• Thioguanine (6-TG)

Still, many of these drugs can cause problems for some men, especially if given in high doses or with other drugs that pose some threat to sperm.

Bone marrow or stem cell transplant

Bone marrow or stem cell transplant usually involves high doses of chemo and sometimes radiation before the transplant. This often permanently prevents a man from making sperm. Talk with your doctor or nurse about this risk before starting treatment.

Radiation therapy

Radiation to a man’s testicles can affect his fertility. Radiation at high doses kills the stem cells that produce sperm. Radiation is aimed directly at the testicles to treat some types of childhood leukemia. Young men with seminoma, a type of cancer of the testicle, may have radiation to the groin area, very close to their remaining testicle. Even when a man has another type of cancer in the abdomen (belly) or pelvis, his testicles may still end up getting enough radiation to harm his sperm production.

Sometimes radiation to the brain may affect the pituitary gland. The pituitary gland signals the testicles to make hormones. Interfering with these signals can affect sperm production and cause problems with fertility.

Surgery

Surgery offers the greatest chance for cure of many types of cancer, especially those that have not spread to other parts of the body. The following types of surgery may affect a man’s fertility.

Testicular surgery

The surgical removal of a testicle is called an orchiectomy. This is a common treatment for testicular cancer. As long as a man has one healthy testicle, he may continue to make sperm after surgery. (Less than 5% of men develop cancer in both testicles.) But some men with testicular cancer have poor fertility because the remaining testicle is not truly normal.

Testicle removal (both testicles)

Some men with prostate cancer that has spread beyond the nearby area may have both testicles removed as a way to stop testosterone production and slow the growth of prostate cancer cells. This is called a bilateral orchiectomy. These men can no longer father children unless they’ve banked sperm before surgery.

Prostate or bladder surgery

For men who have prostate cancer that has not spread beyond the gland, one of the treatments is surgery that removes the prostate gland and seminal vesicles (called radical prostatectomy). The prostate and seminal vesicles are the parts of a man’s body that produce semen. Whether the prostate is removed through a cut in the abdomen (belly) or in the perineum (area behind the testicles and in front of the anus), this surgery leaves men with no semen.

The surgery done to treat bladder cancer is much like a radical prostatectomy, except that the bladder is also removed along with the prostate and seminal vesicles. The testicles still make sperm, but the vas deferens (path to the upper urinary tube) is cut. With sexual stimulation, men can still have the feeling of orgasm, but no fluid comes out of the penis and the sperm cannot get out.

Recently, a few men who had radical prostatectomy have had sperm cells taken directly from their testicles (a minor surgery). The sperm can be used by a fertility specialist to fertilize the partner’s egg in the lab. The fertilized embryo is then placed into the woman’s uterus.

Surgery that interferes with ejaculation

A few types of cancer surgery can damage nerves that are needed to ejaculate semen. They include removing lymph nodes in the pelvis, which may be part of the surgery for testicular cancer and some colon cancers. Nerves are often damaged when removing lymph nodes, and this can cause problems with ejaculation. After these operations, a man still makes semen, but it doesn’t come out of the penis at orgasm (climax). Instead it either shoots backward into his bladder (called retrograde ejaculation) or does not go anywhere. Fertility specialists can gather sperm from these men using several types of treatments including certain drugs, electrical stimulation of ejaculation, or sperm aspiration surgery (sperm cells are taken directly from the testicles).

Other treatments

Hormone therapies used to treat prostate or other cancers can affect your ability to have a child. The effect of some of the newer treatments on fertility, like vaccines, immune therapies, or biological response modifiers, is not yet known. Before you start treatment, it’s best to talk to your doctor, nurse, or other health care professional about its possible effect on your sexual function and fertility.