NEW YORK (Reuters Health) – Overall, women who were treated for cancer during childhood are about 20% less likely to become pregnant than their unaffected sisters, according to data from the Childhood Cancer Survivor Study (CCSS).
Risk factors for infertility identified in the study may be useful for pretreatment counseling, the researchers point out in their article published ahead of print by the Journal of Clinical Oncology.
The CCSS, which is funded by the National Cancer Institute, involves more than 20,000 patients diagnosed with cancer between 1970 and 1986 when they were less than 21 years old, and who survived at least 5 years.
Dr. Daniel M. Green at St. Jude Children’s Research Hospital in Memphis, Tennessee, and co-investigators reviewed the records of 5149 female CCSS participants and 1441 sisters who completed questionnaires between the ages of 15 and 44 years and who were not surgically sterile.
Significant risk factors for reduced fertility identified by multivariate analyses included radiation to the hypothalamus, pituitary, or ovaries, and treatment with alkylating agents, lomustine, or cyclophosphamide.
Specifically, the likelihood of pregnancy was decreased for hypothalamic/pituitary doses greater than 30 Gy (relative risk 0.61). Ovarian/uterine radiation exposure of 5-10 Gy was associated with an RR of 0.56, while a dose greater than 10 Gy conferred an RR of 0.18.
Summed alkylating agent dose scores of 3 or 4 were associated with RRs for pregnancy of 0.72 and 0.65, respectively, compared with no exposure to alkylating agents. Treatment with lomustine (overall RR 0.44) and cyclophosphamide (overall RR 0.80) had dose-related effects, so that treatment in the highest dose tertiles had RRs of 0.31 and 0.11355, respectively.
According to Dr. Green and associates, "These data may be utilized to counsel patients and their parents before initiation of treatment and to identify those at exceptionally high risk for impaired fertility who may benefit from assisted reproduction techniques."
J Clin Oncol 2009;27.