The ailments of old age have taken a toll on Evan Whisenant. In the past few years, she’s dealt with osteoporosis and cataracts. She’s gone through a couple of bouts with melanoma. Her lung function is low, and she has problems with her memory.

Much of this is to be expected as people grow older — but Evan is only 10, a fourth-grader living with her family in Antelope, Calif. And all of these maladies are side effects of the intense radiation and chemotherapy treatments she endured half her lifetime ago, when she beat a rare and especially tenacious form of leukemia.

“It’s almost like this beautiful little soul is living in this body that looks 10 but is really a lot older,” said Evan’s mother, Shannon Whisenant, 34. “She’s so spirited and strong.

“There’s not a day I’m not grateful for her. But there are also points where I wonder who she would have been. The things we did have long-lasting complications.”

This is the reality lurking on the other side of survival. When children are diagnosed with cancer, families fight so hard for them to make it; their lives are a gift. But the miraculous treatments that save childhood cancer patients can also, years after the fact, make them susceptible to secondary cancers and other health problems — a range of illnesses known as late effects.

Now researchers are learning that late effects can include not only the early development of the illnesses of old age but also the premature onset of frailty — physical weakness, exhaustion and low muscle mass seen in people of advanced age.

‘Profound’ problems

The numbers are startling. St. Jude Children’s Research Hospital research shows that 80 percent of adults who beat cancer as kids have a chronic, perhaps life-threatening health condition by the time they reach age 45. More than half have heart abnormalities by that age. Another 65 percent have impaired lung function, and 48 percent have memory impairment.

“We were surprised by the degree of problems, and I think the survivors we studied were, too,” said Kirsten Ness, a St. Jude scientist. “We didn’t expect it to be as profound.”

Cancer itself is a disease of age. Out of an estimated 1.6 million new cases diagnosed this year, says the National Cancer Institute, 75 percent will be in people 65 and older — and only 13,400 will occur in children. Fortunately, as treatments have grown more streamlined and sophisticated, the pediatric oncology survival rate has risen to 80 percent, up from only 20 percent in the 1960s: a major medical success.

The American Cancer Society estimates that 395,000 Americans have survived childhood cancers. But many of them can bear serious, lifelong consequences.

“We want them to survive their cancer, and then we deal with the problems,” said Kay Wells, a pediatric nurse practitioner at the University of California-Davis Comprehensive Cancer Center, which monitors its young patients.

At the clinic Wells runs, called Getting Regular Evaluations After Treatment, she sees children and people in their teens and 20s for annual scans and tests designed to evaluate their specific risks. The goal is to provide them with a thorough summary of their treatment, including drugs and dosages used, as well as guidelines on what their late effects might be. Through an Internet tool called Passport to Care, they’ll be armed with that information wherever they go.

Studying the risks

Researchers know that the risk of late effects depends on the patient’s age and gender, the kind of cancer they had as well as the treatments: surgery, chemotherapy, radiation or stem-cell transplant — or perhaps all of the above.

Children exposed to radiation can be at risk of skin cancers. Those who received steroid treatments can develop osteoporosis. A common chemotherapy drug, anthracycline, increases the possibility of heart problems. Chest radiation can cause lung problems. Cranial radiation can leave patients with cognitive impairment. Infertility can also result from treatment.

People who beat cancer as kids in the 1960s and ’70s are pioneers helping today’s doctors research their survival.

“You can’t take back that you got radiation or chemotherapy, but exercise and diet can reduce your overall risk of late effects,” said Ruth Rechis, a pediatric cancer survivor. “Getting moving again is such an important issue.”