Many women who are survivors of childhood cancer can become pregnant. This good news comes from the Childhood Cancer Survivor Study (CCSS), in which nearly two-thirds of the women in the survivor group who were initially unsuccessful at becoming pregnant eventually conceived—a proportion that is comparable to the pregnancy rate for all clinically infertile women who eventually become pregnant. The study, conducted by researchers from Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and Brigham and Women’s Hospital, is the first large-scale study of female childhood cancer survivors to evaluate outcomes for those women who experienced infertility.1
CCSS was a cohort investigation of 3,531 sexually active women age 18 to 39 years, who were 5-year cancer survivors from 26 medical centers in the United States and Canada. The women in the survivor group were younger than 21 years when they received their diagnoses. Their siblings comprised a control group of 1,366 women in the same age group. The investigators used the standard clinical definition of infertility, attempting to conceive for 1 year or more without success.
“This is the first study to examine direct questions about infertility and the use of infertility services,” said lead author Sara Barton, MD, who was a clinical fellow of reproduction and infertility at Brigham and Women’s Hospital at the time of the study. Barton explained that previous studies used surrogate markers such as parenthood, pregnancy, and births; however, those markers do not take into account the intent to conceive, nor do they consider how long it took to achieve pregnancy.
INFERTILITY IN BOTH GROUPS
The investigators reported that of the 15.9% of the childhood cancer survivor cohort who were infertile, 12.9% had tried to conceive for 1 year or longer. The remaining survivors in the infertile group experienced ovarian failure and may not have even attempted to conceive. Infertility also affected 10.8% of the survivors’ sisters (the control group).
Of the survivors who had been trying to conceive for at least 1 year, 64% were able to achieve pregnancy after trying for an average of 6 more months. The clinically infertile women in the control group who eventually conceived did so after trying for an average of 5 more months, only 1 month less than the survivor group. Similar numbers of women in both groups (69% of survivors and 73% of controls) sought medical help for their infertility. Interestingly, only 42% of the childhood cancer survivors received medication, compared with 75% in the control group.
The risk of infertility was greatest for those women whose cancer had been treated with an alkylating chemotherapy agent or with high-dose radiation to the pelvis or abdomen. The researchers noted that although a number of treatment protocols in pediatric oncology have been revised over the last several decades to reduce late effects, alkylating agents and radiation are still used to treat cancers in this patient population.
Barton suggests triage for fertility preservation of female patients receiving alkylating agents or radiation to the pelvis or abdomen. In addition to being at higher risk to report infertility, female cancer survivors who received those therapies were the least likely to conceive once they had infertility.
This new research could help clinicians offer guidance to their patients based on the treatment protocol for their cancer. For example, patients with a new diagnosis of Hodgkin lymphoma may be slightly more likely to experience infertility, Barton explains, but they do not necessarily need to delay therapy to freeze their eggs. However, the researchers suggest that survivors of childhood cancer should see a fertility expert sooner rather than later if they do not achieve a desired pregnancy within 6 months.
1. Barton SE, Najita JS, Ginsburg ES, et al. Infertility, infertility treatment, and achievement of pregnancy in female survivors of childhood cancer: a report from the Childhood Cancer Survivor Study Cohort. Lancet Oncol. 2013;14(9):873-881.