Like many adults who survived childhood cancer, Karen Cormier always assumed she would never get pregnant.
Cormier, 39, developed a rare form of kidney cancer when she was 5 years old. Chemotherapy helped cure her of the disease, but her doctors warned that the treatments would damage her reproductive organs, almost certainly leaving her infertile.
Cormier, who lives in Massachusetts, saw a fertility specialist when she and her husband were ready to start a family about eight years ago, hoping there was a chance she had survived her early ordeal with her fertility intact. But after two years of trying to conceive without success, they ended the fertility treatments and adopted their son, Luke, in 2008.
Then, three years later, the unthinkable happened: Cormier discovered she was pregnant.
"I was in complete and utter shock," she said. "I couldn't even get the words out to tell my husband."
Cormier gave birth to a son, Ryan, 15 months ago.
"He is a walking biological miracle," she said. "I am just so happy to have two kids I thought we'd never have."
For children with cancer, chemotherapy and radiation treatments are a double-edged sword. Many who live through cancer struggle to conceive once they reach adulthood. Clinical infertility, the failure to conceive after a year of trying, is particularly common among adults who received pelvic radiation and a class of chemotherapy drugs called alkylating agents. At one time, oncologists rarely worried about the reproductive side effects of treatment because so few pediatric patients survived. But as more children with cancer live into adulthood — death rates have plunged 66 percent since the 1970s — the landscape of fertility has changed. Doctors are offering young patients preservation options at the time of diagnosis, and researchers are finding that for many survivors, the odds of overcoming clinical infertility are surprisingly good.
Last month, a large study in the Lancet Oncology found that about two-thirds of female survivors who sought out fertility treatments as adults ultimately became pregnant — a rate of success comparable to that among other infertile women. Other recent studies have found that many men who experience low sperm counts as a result of pediatric cancer treatment, a side effect in two-thirds of boys who receive chemotherapy, can undergo procedures that harvest viable sperm, allowing them to father their own children.
But if fertility treatment is to be successful, time is crucial, said Dr. Lisa R. Diller, the chief medical officer of the Dana-Farber/Boston Children's Cancer and Blood Disorders Center.
"In the setting of having had childhood cancer, if a woman is 25 and has been trying to conceive for six months, then I would say see a specialist," said Diller, the lead author of the Lancet study.
The new goal in the field of cancer fertility, or oncofertility, is to be as proactive as possible, said Dr. Teresa K. Woodruff, chief of fertility preservation at Northwestern University's Feinberg School of Medicine.
Oncologists are increasingly making a point of bringing up the subject of fertility at the time of diagnosis, discussing options like freezing eggs, sperm and embryos before treatment. In younger patients who have not gone through puberty, some fertility clinics offer the option of freezing ovarian and testicular tissue, which can be reimplanted when patients get older.