When 8-year-old Lauren Mulholland started having back pain, her family thought she was having too much fun on the backyard trampoline.
But during a summer vacation at Disney World, Lauren's mother found a lump on her daughter's left side.
A few days later, on Lauren's 9th birthday, she was diagnosed with a Wilms' tumor, a childhood kidney cancer.
After surgery to remove her kidney, two rounds of chemotherapy, and radiation, Lauren, 16, is cancer free, but far from healthy.
Her treatments have left her with chronic health problems that put her remaining kidney in jeopardy.
Lauren's struggle shows how the remarkable progress in the treatment of cancer in the last 30 years has not come without cost, and her story is a familiar one to other childhood cancer survivors.
A landmark study of more than 14,000 patients in this week's New England Journal of Medicine finds that survivors of childhood cancer have frequent and serious health problems.
The Childhood Cancer Survivor Study "points out long-term complications related to specific kinds of cancer treatment," said Dr. Anna Meadows, director of the Pediatric Cancer Survivorship Program at the Children's Hospital of Philadelphia.
Today 80 percent of children with cancer become long-term survivors.
By the time survivors are 30 years out from their cancer diagnosis, however, almost 75 percent of them have a chronic health problem and 42 percent die or have severe life-threatening conditions.
"Those are sobering statistics. The data are shocking and worrisome," said Dr. Kevin Oeffinger, director of the Adult Program for Pediatric Cancer Survivors at the Memorial Sloan-Kettering Cancer Center.
He calls the study, "the most significant paper in the pediatric cancer survivor literature."
The study found that cancer survivors were 3.3 times as likely as their healthy siblings to have a chronic health condition, and 4.9 times as likely to have two or more chronic health conditions including second cancers, fertility problems, heart disease and kidney failure.
Part of the problem, experts say, is pediatric cancer survivors do not seek out cancer specialists as they get older.
Less than 20 percent of adult cancer survivors are followed by cancer centers, and most doctors do not know what to look for or are completely unaware of these increased risks.
Follow-up care is crucial because pediatric cancer survivors "are not out of the woods at any one period of time," said Dr. Lisa Diller, clinical director of pediatric oncology at Harvard Medical School.
Still others "don't come back because they want to forget about the whole experience and get on with their lives," Meadows said.
Those at highest risk are children who had bone cancers, brain tumors and Hodgkin's lymphoma, researchers say.
Lauren is living proof of this struggle.
Because of her treatment, she needed a double lung transplant.
"The radiation was really bad. That is what damaged her lungs," said her father, Bob Mulholland.
"At the time of her transplant, her lung function was only 9 percent and doctors told us Lauren had only three weeks to live," said Terri Mulholland, Lauren's mother.
Lauren is malnourished -- she weighs 83 pounds and gets feedings overnight through a stomach tube.
The medicines Lauren takes to prevent her body from rejecting her new lungs are now damaging her only kidney.
"I am really worried about my kidney," Lauren said.
Future Health Problems Come As a Surprise