The first generation to survive childhood cancers in large numbers is discovering that some of the same treatments that destroy tumors with toxic force can cause serious side effects to surface years later.
As more children outlive their cancers, doctors are drawing links between curative therapies and delayed problems such as early puberty, sterility, stunted growth, learning disabilities and weakened hearts.
At the Johns Hopkins Oncology Center, physicians are taking a second look at cured patients to see if they are suffering long-term effects of treatment.
They have found people like Chris Staub, 8, a second-grader from Pennsylvania who has already entered puberty because radiation prematurely flipped a hormonal switch in his brain. When he was just a year old, X-rays destroyed a malignant brain tumor.
Then, there's Eric Kincaid, 26, of East Baltimore, who survived leukemia at 10 but quit school in the 10th grade because he couldn't concentrate and complete his work -- the possible result of radiation treatments that targeted his brain.
Delayed side effects are a cruel blow for many people who ended years of surgery, chemotherapy and radiation believing the ordeal of cancer was over.
Learning the cause, however, can be strangely liberating.
"In a weird kind of way, it was gratifying, like turning on a light," Mr. Kincaid said. "At least I know it's not totally me."
As many as 10 percent to 15 percent of children who survive cancer suffer severe complications in the years that follow -- while up to a quarter suffer mild to moderate symptoms, some studies show.
Radiation treatments that burn away brain tumors also can hinder learning, retard growth and spawn new cancers. One class of anti-cancer drugs can weaken the heart, placing patients at risk for heart failure as they age.
Some drugs damage sex organs, forcing youngsters to face the prospect that they will never conceive when they grow up.
This year, doctors and nurses at the Johns Hopkins Oncology Center have begun to track patients who were declared cured five, 10, even 20 years ago. Their goal is to document and help people overcome the delayed consequences of treatments -- and to fashion therapies that are less damaging but no less effective.
Hopkins has contacted 100 of the 700 people who have survived at least five years past therapy. Doctors and nurses are evaluating five new patients a week, and hope to see 200 survivors by year's end.
Many people are hearing for the first time that treatments that saved their lives might explain why they can't keep up in class or hold down a job.
"Some of the problems are subtle," said Dr. Cindy Schwartz, who heads the "late effects" clinic at the Johns Hopkins Oncology Center.
"Some of these children are not retarded, but school is a little more difficult for them. They were passed along in the school system. They were quiet and didn't get great grades, and they ended up not learning a lot."
Long-term effects weren't much of a problem in years past, when cancer simply killed the vast majority of its young victims. In the 1960s, for instance, doctors cured only about 10 percent of afflicted children.
The ballyhooed War on Cancer has failed on many fronts -- such as curbing breast cancer deaths -- but it has scored shining victories against childhood leukemia and some solid-tumor cancers. Today, doctors estimate that two-thirds of afflicted youngsters will survive their malignancies.
Dr. Curt I. Civin, chairman of pediatric oncology at Hopkins, said he cannot credit revolutionary treatments. There have been few, but doctors have become more creative in deploying old drugs along with radiation and surgery.
Doctors, for instance, have learned to use chemotherapy drugs in combinations rather than singly.
This way, if a tumor becomes resistant to one drug, it might succumb to another before it gathers strength and grows.
"But these battles are being won with drugs that aren't very smart," Dr. Civin said.
Drugs that poison tumors are equally capable of damaging organs, glands and brain cells, he said.
James and Kimberly Staub of New Oxford, Pa., didn't worry much about long-term effects when their son Chris, at the age of 1, was diagnosed with a brain tumor.
They wanted him cured.
The diagnosis explained why their little boy leaned into people's faces in order to see them, why he crashed into doors and why his eyes jumped from side to side.
L The tumor, resting against the optic nerve, had to come out.
The Staubs weren't surprised that surgery, radiation and chemotherapy left him legally blind. The tumor's location virtually ensured that.
He has coped well. In school, he learns quickly and gets good grades. He is helped by a classroom aide who stays by his side throughout the school day and an optical device that greatly enlarges print on a screen.
But he has trouble sitting still or concentrating on tasks for long. Doctors have learned that radiation and drugs that target the brain can produce symptoms of attention deficit disorder.
His father says he also seems to lack judgment despite his
capacity to learn. One day in school, he bolted from his seat and pulled a fire alarm.
"He doesn't realize that if he walks out in front of a car, it could kill you," Mr. Staub said.
While bathing Chris earlier this year, Mrs. Staub was astonished to find that he was developing body hair.
Doctors immediately recognized this as the premature onset of puberty, which would inevitably trigger a teen-age growth spurt and other unsettling changes if not arrested.
Just as bad, puberty would end far ahead of schedule, causing him to stop growing just as his peers launched into adolescence.
Although prematurely tall, he ultimately would stand in the shadow of his classmates.
Physicians are reasonably confident that radiation or the tumor itself pulled a biological switch in the hypothalamus, a region in the brain that sets the clock for puberty and other hormonal changes.
Dr. Leslie Plotnick, a pediatric endocrinologist at Hopkins, said there is a reliable remedy if tests confirm the cause.
Chris would take injections of synthetic hormones, which would arrest puberty immediately. He would take the injections until he reached his early teens, when nature would be allowed to run its course.
"These drugs are amazing," said Dr. Plotnick. "Each time you do it and watch the puberty regress, it's like a miracle."
For some survivors, remedies are harder to find.
Eric Kincaid said he had little trouble tolerating the drugs and radiation that helped him defeat leukemia. But he was unprepared for the aftermath.
When he returned to school, he had trouble sitting still and focusing on classwork. He suffered from dyslexia before his cancer, but words and letters became a hopeless jumble after he was cured. He rarely finished assignments on time and, by 10th grade, he simply stopped trying. At 17, he dropped out.
Chemotherapy sapped his fingertips of their dexterity. He struggles to button his shirt with fingers that feel bound by a tight pair of gloves. And doctors tell him that the drugs probably made him sterile, although he has not taken tests to confirm it.
'Outside looking in"
Mr. Kincaid, who displays a wide vocabulary and an easy affability, has worked sporadically as a cook's assistant and, more recently, as a stock clerk in a Fells Point five and dime.
He was fired from his last job because he couldn't work fast enough. Now, he fights depression and wonders how he will ever become self-sufficient and move from his parents' home in Highlandtown.
"I always aspired to go to college, always thought of myself as an intellectual. But I've always felt I was on the outside looking in, my whole life."
Filled with self-blame, he never suspected his cancer treatments were even remotely linked to his problems until recently, when he stumbled into the Hopkins program and got an evaluation.
Armed with new knowledge about "late effects," doctors are working to fashion new treatments that are less injurious in the long run.
They have reduced the use of cranial radiation and, in some cases, trimmed chemotherapy doses without compromising results. They are also trying to balance heart-damaging drugs with medications that reduce blood pressure. This could make it easier for a weakened heart to do its work.
When side effects cannot be avoided, doctors can reduce the impact by warning patients. Teen-age boys who might become sterile can bank sperm before starting chemotherapy. Young women at risk for early menopause can consider having children earlier than planned.
"Sometimes it just helps to say, it's going to take you three times as long to learn a new computer or a new cash register," Dr. Schwartz said. "This is because of your disease."
Although cancer researchers are looking for harmless cures, the search has been difficult.
"I've become resigned to the fact we're going to be using these toxic treatments for some time," said Dr. Civin.
"We have a lot of cured patients out there. It would be morally bankrupt to treat patients with such toxic drugs without providing for their best care later."
In the meantime, doctors are tracking today's survivors to see if further problems emerge as they age.
"The real question," said Dr. Schwartz, "is what's going to happen to these patients when they reach their 50s and 60s, when most of us have deterioration of organs."