New cancer drugs may have their biggest impact on the littlest patients. Conventional treatments have worked wonders in children with cancer: before 1970, young patients had little chance of survival; today, three quarters make it past the critical five-year mark. But standard chemotherapy and radiation can ravage a child's body and brain in ways that may not show up until years later. Greta Greer, manager of the American Cancer Society's Cancer Survivors Network, says: "It's not all over when the treatment is over."
In the 1970s and '80s, when the majority of today's adult survivors of childhood cancer were treated, pediatric oncologists were focused first and foremost on saving their patients, despite the toxic cost. Children with leukemia, for example, routinely received radiation to their heads and spines to prevent cancer cells from infiltrating the fluid around their brains. While the treatment helped contain the cancer, it also damaged healthy neurons, leading to learning disabilities or attention problems later on in some patients. It caused physical injury as well, as Amorette Dye-Vinson, 26, can attest. At 3, she received radiation to treat a spinal-cord tumor. The treatment interrupted the development of her thyroid and badly damaged the vertebrae in her neck; as an adult, she takes thyroid medication and has undergone multiple spinal fusions. Chemotherapy, for its part, can damage cells in the cardiac muscle, causing heart failure years after a child's cancer has been cured.
Conventional therapy can also cause stunted growth, infertility, lung damage and even secondary cancers. In a landmark study of more than 9,500 adults who were treated for childhood cancer, published in The Journal of the American Medical Association in September, researchers reported that cancer survivors diagnosed between 1970 and 1986 were far more likely than their siblings to report health problems or to suffer from some kind of functional impairment, like needing help with bathing or everyday chores, after tumor removal or amputation.
Today minimizing side effects is a priority. Over the past 30 years doctors have learned how to dial back on toxic therapies--reducing doses of chemotherapy and, in some cases, even eliminating radiation--without affecting survival. As with adults, the goal is targeted treatment, so drugs like Gleevec and Iressa are now being tested in children. The trials must proceed cautiously, says Dr. Barry Anderson, a pediatric oncologist at the National Cancer Institute: "We don't want to compromise our success at curing childhood cancer with conventional therapy."
If the new drugs work, the payoff could be enormous. Already, survivors of childhood cancer are a resilient group. The most powerful finding in the JAMA study, says lead author Dr. Melissa Hudson of St. Jude Children's Research Hospital in Memphis, Tenn., is that despite the long-term problems caused by treatment, the vast majority of adults rated their health as good or excellent. "Even the worst of these side effects is so much better than the cancer," says Dye-Vinson. "I'm feeling great." As treatments improve, that resiliency will only get stronger.