A new study has welcome news for women who have survived childhood cancer and are trying to conceive—chemotherapy doesn't significantly reduce fertility.
Cancer treatments have long been thought to affect fertility, but are unfortunately a necessary side effect of saving a life. Whether children being treated for cancer will be able to have their own children later on is often a far-off concern for parents. A new study published in The Lancet Oncology, though, has promising news for women who've survived childhood cancer: Their ability to get pregnant is almost the same as women unaffected by cancer.
Women's fertility less affected than men's
Researchers looked out over 10,000 male and female survivors of childhood cancers, such as leukemia and Hodgkin disease, and compared them to 4,000 of their siblings. "We found that among these survivors, all of whom received primarily chemotherapy without any radiation to the pelvis or brain, that female survivors appeared to have almost a similar rate of pregnancy as their siblings—only about a 10 to 15 percent difference," lead author Eric Chow, M.D., of the Fred Hutchinson Cancer Research Center in Seattle, tells Fit Pregnancy. But, male survivors had a much lower rate of achieving pregnancy compared to their siblings—almost 40 percent less.
Why is there such a big difference in ability to have children between male and female survivors? "For males, sperm are actively being produced by stem cells even in [prepubescent] boys, and are known to be very sensitive to chemotherapy," Dr. Chow says. "If enough of these stem cells are knocked off by chemotherapy, infertility can occur due to lack of sufficient sperm following treatment."
For women, the impact of chemo on fertility is less understood. "I don't think the exact effects of chemotherapy on women, and their eggs, are clear," Dr. Chow says. "Women are born with their full complement of eggs, and chemotherapy may have direct effects on eggs or surrounding support cells that eggs need." What is clear from his study, though, is that older women were less likely to get pregnant than their siblings. "Other studies have shown that female cancer survivors have a higher risk of premature or early menopause," Dr. Chow says. "We think that although women who received chemotherapy alone may be able to achieve pregnancies almost as readily as siblings early on, that their overall fertility 'window' may be shorter. This is suggested by the substantially decreased pregnancy rate among women ages 30 to 45 in this study."
This study was most important because it looked at the effects of chemotherapy alone—most other large studies also included radiation therapy. Radiation is known to lead to fertility problems, so it's being used less with children, of whom 80 percent survive long-term. In looking at different types and doses of chemo drugs used, this study can help doctors and parents better understand the risks to children's fertility.
Preserving childhood cancer patients' fertility
If you're a childhood cancer survivor trying to conceive, Dr. Chow says to discuss the possible impact of your treatment with your doctor. For women who've had chemo or radiation, "it probably wouldn't hurt to consult with a reproductive medicine specialist to better assess their reproductive potential," he says. If you're not quite ready to start a family but are in your thirties, or are going to delay until you're in your thirties, he also says to consider freezing your eggs.
Unfortunately for parents of young children with cancer, little can be done to protect their future fertility. "There are no current accepted methods for fertility preservation in girls who have not yet started [their period]," Dr. Chow says. "No standard options exist currently for boys diagnosed prior to puberty" either. Boys who've passed puberty can bank their sperm; but since retrieving eggs is invasive, parents of girls who've entered puberty should discuss the risks and benefits with their doctors.
Although cancer is among every parent's worst fears, Dr. Chow says there's no need to worry until it happens. "Childhood cancer is so rare, I hope no one is thinking in advance what they would do if their child got diagnosed with cancer," he says. For survivors trying to get pregnant, though, his study provides some hope. "Chemotherapy, especially certain drugs and at higher doses, can still have considerable effects on the fertility potential of boys or young men receiving treatment—however, the news for girls or young women is more encouraging," he says.