Although there are no official guidelines determining the length of time to wait after cancer treatment before attempting pregnancy, clinical nurse specialist Joanne Frankel Kelvin, RN, MSN, AOCN, of Memorial Sloan Kettering Cancer Center in New York, who established a program called Cancer and Fertility, says it is generally recommended to wait at least one year. "There are generally three factors for a woman to consider. These include making sure that (1) eggs that have been exposed to chemotherapy or radiation and may have been damaged are no longer in her body, (2) she is fully recovered from her treatment and its effects, and (3) she has been 'cleared' by her oncologist because an acceptable period of time has passed in which she is not likely to have a recurrence."
Discussions With A Cancer Care Team Are Important
Kelvin also says that it is important for women to discuss the safety of pregnancy after treatment with their oncologists. Although many women treated for cancer are able to carry a pregnancy without any problems, some treatments have late adverse effects on some organs, such as the heart, lungs, or uterus, that can put her at risk of complications during pregnancy.
Must A Pregnancy After Cancer Be High-Risk?
In general, most pregnancies in cancer survivors are managed the same as pregnancies in other patients of similar age. "However, some women may have medical problems related to prior cancer treatment exposures, including hypothyroidism, or problems with heart or lung function, and may require the care of a maternal fetal medicine specialty obstetrician. Initial consultation with a woman's OB/GYN can help in making this decision," says Erica L. Mayer, MD, MPH, medical oncologist, Dana-Farber Cancer Institute in Boston. "Patients who become pregnant after a cancer diagnosis do not need routine specialized obstetrical monitoring compared with other same-age women who are pregnant. An obstetrician may consider evaluating baseline heart function in a woman who has had exposure to a potentially cardiotoxic medication, and will monitor fetal growth closely. However, pregnant cancer survivors also need to continue routine oncologic follow-up care throughout pregnancy and postpartum periods."
There are two primary risks a woman must consider when deciding about pregnancy after a cancer diagnosis. Dr. Mayer says the first consideration is what is her risk of cancer recurrence? "In general, most women prefer not to attempt pregnancy unless their personal risk of cancer recurrence is low," she says. "Also, will the pregnancy increase the chances of cancer coming back? This is a relevant concern for hormonally driven cancers, such as some forms of breast cancer, or cancers that require prolonged oral therapy that cannot be taken during pregnancy."
More than any other cancer type, breast cancer is the type of cancer that typically complicates a woman's plans to get pregnant. Although research on the safety of pregnancy after a breast cancer diagnosis is limited, says Dr. Mayer, the available data suggest no apparent increased risk of breast cancer recurrence in women who choose to get pregnant after their cancer diagnosis. In general most providers encourage women to wait 2 to 3 years after completion of therapy or, if possible, until completion of any oral cancer therapy, such as tamoxifen.
How Does Cancer Treatment Impact A Woman's System?
According to Dr. Mayer, systemic chemotherapy can be toxic to ovary function and can lead to temporary or permanent menopause. The risk of permanent menopause depends on a woman's age as well as the type and amount of chemotherapy. Radiation therapy to the pelvic area can affect ovary function, but radiation elsewhere should not have an effect.
For patients interested in fertility preservation, a visit to a reproductive endocrinology specialist is encouraged prior to embarking on therapy. Techniques offered can include sperm banking as well as embryo harvesting via in vitro fertilization. "In vitro fertilization is a technique offered to female patients prior to initiation of cancer therapy to harvest eggs for fertilization," Dr. Mayer explains. "Although there are theoretical concerns about exposure to hormonal agents in patients with a new breast cancer diagnosis, in the majority of cases providers believe a single cycle of in vitro fertilization is safe and acceptable."