Adults who survived childhood cancer are facing a new health challenge: premature aging.
As more survivors reach their 30s and 40s, researchers are noticing health problems more common to much older people, such as frailty and serious memory impairment.

"Their overall physical being resembles that of people 30 years older than they are,'' said Kirsten Ness, associate member of the Department of Epidemiology and Cancer Control at St. Jude Children's Research Hospital in Memphis. She is one of the authors of a number of studies looking at premature aging in childhood cancer survivors.
The research is being driven by the growing number of childhood-cancer patients who now are adults—survival rates for many childhood cancers rose over recent decades—and the emergence of programs that follow them. Some experts estimate that one in every 640 adults aged 20 to 39 had cancer when he or she was a child.
One of the largest programs looking at the health risks of childhood cancer survivors is the St. Jude Lifetime Cohort Study, which follows people who were treated at St. Jude between 1962 and 2003. The subjects return to the hospital for regular testing and assessment.
Last month, St. Jude researchers reported in the Journal of Clinical Oncology that adult survivors of childhood cancer are far more likely than other people their age to be frail, with slow walking speed, low muscle mass and weakness more common to people decades older.
In the study of 1,922 survivors, researchers reported 13.1% of women and 2.7% of men were frail. In a comparison study looking at 341 people who had no history of cancer, none were frail.
Brandy Wilbanks, who was diagnosed with osteosarcoma, a bone cancer, at 13 and had a relapse at 16, is now showing signs of frailty at age 32. She took an exercise stress test as part of the St. Jude Lifetime study that showed she had fitness levels comparable to a 65-year-old woman.
Ms. Wilbanks, who works long shifts as an oncology nurse at a Memphis hospital and is the mother of a 2-year-old son, said she knows that many of her health challenges are uncommon among people her age. "You don't hear about 32-year-olds falling and breaking a hip, but I have to worry about that because of what I've gone through,'' she said.
Researchers are grappling with the cause of the premature aging. They have focused on the treatment the survivors received at a time when their brains and other organs were developing.
Children who had acute lymphoblastic leukemia, for example, and were treated with high doses of radiation to the brain are showing signs of brain changes and memory problems comparable to people who are 70, said Gregory T. Armstrong, a pediatric oncologist at St. Jude who is an author of a study published earlier this year.
"The treatment that saved their lives caused an injury to their brain,'' he said.
Researchers are also examining the role of chemotherapy on premature aging. The concerns have led to efforts to use lower doses of medicine and avoid radiation when possible.
Some researchers think that genetic or other factors also may make some survivors more susceptible to premature aging.
Tim A. Ahles, director of the Neurocognitive Research Laboratory at Memorial Sloan-Kettering Cancer Center in New York, said that in studies of younger women with breast cancer, some had lower-than-expected cognitive function based on age, occupation and education before beginning any treatment, "so there is some suspicion that the cancer itself may also be implicated in the development of the cognitive problems and the accelerated aging.'' Data remain sparse, he added.
Cancer researchers first noticed premature aging in younger survivors because "the aging is more dramatic in someone younger,'' Dr. Ahles said. New studies are under way in people diagnosed with cancer in their 60s, and some of these survivors also seem to be at risk for accelerated aging.
"The biology of cancer and the biology of aging are linked together in complicated ways,'' said Dr. Ahles. "It makes sense that the cancer itself or the genetic susceptibility to cancer may also influence how one ages.''
Other researchers are examining childhood cancer survivors who show signs of cognitive issues.
Ronald C. Petersen of the Mayo Clinic in Minnesota, who focuses on Alzheimer's and mild cognitive impairment in the general population, worked with St. Jude researchers on a study in which they gave young survivors standard memory tests and magnetic resonance imaging, similar to the diagnostics used for people at risk for Alzheimer's.
The survivors resembled people with mild cognitive impairment, he said. They could hold down jobs and have normal social interactions, but the worry was the problems would progress to early-onset memory loss and dementia. More studies are needed, he said.
Kevin C. Oeffinger, director of the Adult Long-Term Follow-Up program at Memorial Sloan-Kettering, said doctors are working to boost patients' physical activity, build muscle mass and other steps to address frailty and other health problems.
"We don't want to be satisfied with curing the cancer, then the patient dies at a younger age from something we could have prevented,'' he said.