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
For cancer survivors, health problems start to appear in early adulthood and continue to add up over a patient's lifetime.
Sadly, the elation of being labeled "cured" is replaced by shock and anger when other health problems occur.
It can be hard for families to comprehend the magnitude of these risks "at the time of diagnosis and treatment," said Dr. Melissa Hudson, director of the Cancer Survivorship Division at St. Jude Children's Research Hospital.
Lauren said, "I had no idea my cancer would affect my lungs."
It is important for primary-care doctors to be on the front lines of monitoring cancer survivors, but access to care is a serious obstacle.
"Health insurance is difficult to get or afford if you are a cancer patient," Oeffinger said.
Despite the bothersome findings, "there is definitely a silver lining," Oeffinger said.
More than 98 percent of childhood cancer survivors were still alive at the study's conclusion, a feat that would have been almost unimaginable 50 years ago.
"There is always a chance that you can get all kinds of bad things, but at the time what are your choices?" Lauren's mother asked.
Now doctors can begin to improve the treatments that are responsible for the lingering health problems.
Efforts by the Childhood Cancer Survivor Study and organizations like the Lance Armstrong Foundation will someday help cancer patients live longer and healthier lives.
"The No. 1 lesson is that we have to pay attention to long-term consequences," said Les Robison, chair of epidemiology and cancer control at St. Jude.
Experts say the best thing survivors can do is to arm themselves with knowledge of their medical history.
Educating patients and their parents about the dark side of being cured of childhood cancer will not only keep patients cancer free but also disease free.
Lauren's advice to cancer patients is simple: "It might not be over as soon as the treatment is over, but you'll get there."