Fertility Risks
Who is at risk?
Every year in the U.S., approximately 1.5M people are diagnosed with cancer. Almost 10% of these new diagnoses occur in people who are 45 years old or under. Many of these 150,000 people have not yet had children, have not completed their families, or, in fact, are still children themselves. For these patients, preserving their fertility and protecting their parenthood options is an important part of their survivorship and life after cancer.
Why is fertility a concern?
Cancer can take its toll on fertility in two ways.
First, the cancer itself may directly affect the reproductive system. This occurs when there is cancer of the reproductive organs including the ovaries, uterus, cervix and testes. Sometimes patients have impaired fertility, possibly due to the stress of their illness on the body, even before they begin their cancer treatments.
Second, the cancer treatment, including chemotherapy, radiation, and surgery can damage the reproductive system. Some treatments – certain chemotherapies and radiation – are gonadotoxic, meaning they will destroy sperm and eggs – and therefore cause infertility. Some treatments, principally surgery, but also radiation, can cause mechanical damage to the reproductive system, through the removal of reproductive organs or damage to their ability to function.
For more detailed information, see Factors Affecting Risk below.
Patient Population at Risk
About 10% of new cancer diagnoses in this country occur in patients age 45 and under, a time when many people are in the midst of building their families.
In the United States, many men and women are starting their families later than they used to. Data from the U.S. Centers for Disease Control and Prevention (CDC) show that the national average age for first births among U.S. women rose from 21.4 in 1970 to 25.0 in 2006. As a result, may patients who are diagnosed in their 30s or early 40s who may have completed their families a generation ago, today, may just being getting married and thinking about parenthood.
Survivorship rates are rising, too. The American Society of Clinical Oncology (ASCO) reports that an estimated 379,000 people in the United States are survivors of childhood and adolescent cancer, diagnosed before age 20. ASCO adds that 83% of children and adolescents diagnosed with cancer will live at least five years or more following their treatment. While this represents a great advance in treatment, many of these survivors are now facing the late effects of their earlier cancer treatments, including infertility.
Factors Affecting Risk
Age and treatment type can influence a cancer patient’s risk of infertility.
Chemotherapy uses powerful drugs – alone or in combination – to kill cancer cells, shrink tumors, and/or stop the disease from spreading to other parts of the body. The drugs may be administered in pill or liquid form, as an injection, or intravenously. Chemotherapy may be used with surgery or radiation as part of a patient’s treatment plan.
In addition to killing cancer cells, unfortunately, these powerful drugs also can kill healthy cells throughout the body, including egg and sperm cells. They may also affect the genetic makeup of these cells.
Factors Influencing Risk
It is difficult to know exactly how, and to what extent, fertility will be impaired by chemotherapy. Several factors influence the risk that infertility will occur, which makes it challenging to predict what the fertility outcome will be for an individual patient.
Drug Type: Some types of chemotherapy drugs take a stronger toll on fertility than others. Alkylating agents tend to be the most toxic. These drugs include: busulfan, carmustine, chlorambucil, cyclophosphamide, lomustine, mechlorethamine, melphalan, procarbazine.
Dose and Duration: Dosage and treatment durations can also impact a patient’s fertility. Generally, higher doses and longer duration’s tend to do more damage.
For women, because they have a fixed supply of eggs, age is a significant factor. Fertility in younger women, who have a larger pool of eggs, may be able to withstand stronger doses and longer treatment duration’s when compared to older women. Females who have chemotherapy before puberty might regain their ovarian function as adults.
For men, because they continue to produce sperm over their lifetime, the damage to their sperm may be temporary. Unless his sperm-producing cells are also damaged, a man may regain his ability to produce healthy sperm. If this is going to occur, it usually happens within a few years of the completion of treatment.
Patients should know that radiation therapy uses high-energy x-rays, gamma rays, and/or charged particles to damage the DNA of cancer cells. When this occurs, the cancer cells can no longer divide and spread. Many of them die.
While radiation targets cancer cells, it is inevitable that some healthy cells are damaged in the process. Depending on the treatment area, this can include egg and sperm cells. Reproductive organs and glands that produce related hormones can also be damaged.
Here are some examples of ways radiation can affect fertility:
• Radiation in other parts of the body, such as the brain (particularly the pituitary gland), can interfere with hormonal processes needed for fertility.
• Radiation to a man’s pelvis, abdomen, or lower spine can damage his testes, interfering with his ability to produce sperm. It may also lower his sperm count, damage sperm integrity, or impair the normal transport of sperm.
• Similarly, radiation to a woman’s pelvis or abdomen can affect any of the reproductive organs within the radiation field. Radiation to the ovaries themselves can destroy eggs, disrupt egg production and diminish egg quality.
• In addition, women who have radiation to the uterus or cervix may have difficulty becoming pregnant or carrying a pregnancy to term. They are also at higher risk for miscarriage, preterm labor, and having low birth weight babies.
• Total body irradiation (TBI), used for stem cell and bone marrow transplants, involves radiation to the entire body. Due to the extensive nature of the treatment, most men who undergo TBI typically have azoospermia (no sperm) afterward. Most women who have this treatment experience ovarian failure.
Factors Influencing Risk
Location: Radiation is directed at a particular area of the body, where there are cancer cells. This targeted treatment area, along with surrounding tissues, are subject to the most damage from radiation. Therefore, reproductive functioning is impacted only by radiation to or near organs that are part of the reproductive system (as described above). Radiation to other parts of the body, such as the extremities or the upper chest, should not affect fertility.
Dose and Duration: Typically, the higher the dose of radiation, the greater the likelihood of damage.
Concerns for Men
Surgery to remove one testis or both testes can have an impact on a man’s fertility. If only one testis is removed, he may still be able to father a child because the remaining testis can compensate for the one that is lost. However, if both testes are removed, sperm production is no longer possible.
Some men who have surgery affecting the prostate, bladder, urethra, or colon experience retrograde ejaculation. Instead of ejaculating forward out of the urethra, semen travels backward into the bladder and exits the body when a man urinates.
Retrograde ejaculation is not harmful, but it does prevent fertilization, as sperm cells cannot reach the egg cell.
Concerns for Women
Women who have both ovaries removed will undergo surgical menopause and no longer produce egg cells. If only one ovary is removed, conceiving is still possible.
Surgical removal of the uterus, cervix, and/or both fallopian tubes may prevent a woman from conceiving and carrying a baby to term.
Fertility-preserving surgery may be possible, however. For example, some women with early-stage cervical cancer have their cervix removed, but their uterus remains. This can make carrying a baby possible, although delivery must occur via Caesarian section.
References
- American Society of Clinical Oncology; “About Cancer Survivorship”; http://www.cancer.net/survivorship/about-cancer-survivorship
- Centers for Disease Control and Prevention; Mathews, T.J., MS and Brady E. Hamilton, PhD; “Delayed Childbearing: More Women Are Having Their First Child Later in Life”; (August 2009); http://www.cdc.gov/nchs/data/databriefs/db21.pdf
- National Cancer Institute; “Estimated New Cancer Cases and Deaths for 2014 All Races, By Sex”; http://seer.cancer.gov/csr/1975_2011/browse_csr.php?sectionSEL=1&pageSEL=sect_01_table.01.html
- OncoLink (Penn Medicine); Vachani, Carolyn, RN, MSN, AOCN; “Female Fertility and Cancer Treatment” (Last modified: October 6, 2006); http://www.oncolink.org/coping/article.cfm?c=534&id=990
- OncoLink (Penn Medicine); Vachani, Carolyn, RN, MSN, AOCN; “Male Fertility and Cancer Treatment”; (Last modified: October 6, 2006); http://www.oncolink.org/coping/article.cfm?id=992&aid=1496
- Sexual Medicine Society of North America; “Overview – Retrograde Ejaculation”; http://www.sexhealthmatters.org/retrograde-ejaculation/overview-retrograde-ejaculation
- American Cancer Society; “Questions about chemotherapy”; (Last medical review: March 25, 2013); http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/chemotherapy/whatitishowithelps/chemo-what-it-is-questions-about-chemo
- American Society of Clinical Oncology (ASCO); “Fertility Concerns and Preservation for Men”; (Reviewed and approved: March 2014); http://www.cancer.net/coping-and-emotions/sexual-and-reproductive-health/fertility-concerns-and-preservation-men
- MD Anderson Cancer Center; “Preserving Fertility Before Treatment”; http://www.mdanderson.org/patient-and-cancer-information/cancer-information/cancer-topics/detection-and-diagnosis/preserving-fertility/index.html
- Up to Date; Hayes, Francis J. MD and Glenn J. Bubley, MD; “Effects of cytotoxic agents on gonadal function in adult men”; (Last updated: September 2, 2014); http://www.uptodate.com (access by subscription only)
- American Cancer Society; “Understanding Radiation Therapy”; (Last revised: May 2, 2014); http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/radiation/understandingradiationtherapyaguideforpatientsandfamilies/index
- American Society of Clinical Oncology (ASCO); “Fertility Concerns and Preservation for Women”; (Reviewed and approved: March 2014); http://www.cancer.net/coping-and-emotions/sexual-and-reproductive-health/fertility-concerns-and-preservation-women
- National Cancer Institute; “Radiation Therapy for Cancer”; (Reviewed: June 30, 2010); http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation
- International Society for Sexual Medicine; “Can ovary removal have effects on sexual health/functioning?”; http://www.issm.info/education-for-all/sexual-health-qa/can-ovary-removal-have-effects-on-sexual-health-functioning/;
- International Society for Sexual Medicine; “How might removal of one or both testicles affect a man’s sex life?”; http://www.issm.info/education-for-all/sexual-health-qa/how-might-removal-of-one-or-both-testicles-affect-a-mans-sex-life/