FRIDAY, Jan. 17, 2003 (HealthDayNews) -- Survivors of childhood brain tumors are at risk of developing other serious medical problems later in life, from hormonal imbalances to osteoporosis to stroke.
That's the conclusion of a new study that found that about 43 percent of teenagers and young adults who survived at least five years after being treated for a cancerous brain tumor experienced at least one "adverse endocrine event." And 18 percent experienced an "adverse cardiovascular event," the study says.
Endocrine events included hypothyroidism, growth hormone deficiency, delayed puberty and osteoporosis. Cardiovascular events included stroke, blood clots or angina-like symptoms associated with cardiovascular disease.
"One of the points of this study is for us to get both childhood brain tumor survivors and primary-care physicians to be aware of the problems that can occur many years down the line," says Dr. James Gurney, lead author of the study.
"The survivors of brain tumors need to let their physicians know about the treatment they had and be vigilant about monitoring their health throughout their lifetime," adds Gurney, an epidemiologist and associate professor of pediatrics at the University of Minnesota in Minneapolis.
The study appears in the Feb. 1 issue of Cancer.
Gurney and his colleagues surveyed 1,607 young adults who were treated for a brain tumor between 1970-86 and had survived at least five years. They compared their medical histories to those of 3,418 siblings of childhood cancer survivors.
Information about how their cancer was treated -- chemotherapy, radiation, surgery or some combination of the three -- was obtained from their medical records.
The researchers found the survivors of brain tumors were 14 times more likely than the siblings to develop hypothyroidism, 278 times more likely to develop growth hormone deficiency, and 25 times more likely to develop osteoporosis.
Although the numbers sound terrifyingly high, Gurney says, the findings can be stated another way: 6.6 percent of young adult brain tumor survivors reported hypothyroidism first occurring five years after diagnosis; 21 percent developed growth hormone deficiency, and 1.8 percent developed osteoporosis.
That means the absolute risk of getting osteoporosis, for example, is actually quite small, but the relative risk is much higher for survivors of brain tumors because the rates of osteoporosis among the young is typically very small, Gurney explains.
The study also found that childhood brain tumor survivors were nearly 43 times more likely to have a stroke, six times more likely to develop a blood clot, and twice as likely to develop angina-like symptoms, such as chest pain and shortness of breath, which may indicate heart disease.
Put another way, 2.4 percent had a stroke five years or more after their brain tumor was diagnosed, 1.9 percent had a blood clot, and 4.4 percent had symptoms of angina.
Researchers found the type of treatment had a big impact on how many medical problems survivors faced later on.
Children who received chemotherapy, surgery and radiation were at the highest risk of later complications.
Those who had surgery only were the least likely to have problems, while the risk of children who had only surgery and radiation fell somewhere in between.
The dangers of radiation to the young are well known, says Dr. Herman Kattlove, a medical oncologist for the American Cancer Society. Doctors try to avoid giving radiation to children under age 3, and ideally under age 5.
At that age, the brain is forming all sorts of connections, and radiation can cause a devastating disruption that can have lifelong implications, Kattlove says.
However, radiation is more effective at killing brain cancers than chemotherapy because of the blood-brain barrier, a membrane that deters drugs from entering the brain.
"The problem is you're dealing with a deadly disease and you have to do something," Kattlove says. "The good news is our treatments are becoming so good, more children are surviving. Now, we're taking a step back to really look at how we are treating people. This is occurring because the child is alive. It's better than a dead child."
About 54 percent of children with brain tumors in 1976 survived five years or more. The survival rate rose to 70 percent in 1998, according to the study.
Because so many more children are surviving, it's becoming more and more important to figure out what treatments put a child at risk of long-term difficulties, says Dr. Patricia Shearer, a pediatric oncologist at the Ochsner Clinic Foundation in New Orleans.
"This study is very important because it enables us to identify and predict the problems that are likely to happen in children later on," Shearer says.
More information
To learn more about children and brain tumors, visit the Children's Brain Tumor Foundation or the National Cancer Institute.
