FORT LAUDERDALE, Fla. -- Alarmed at the seemingly high rate of brain cancer among children in St. Lucie County, Fla., a group of mothers who courted controversy with their calls for a major health study are starting to feel vindicated.
Last summer, the mother of a child who died organized other families, raised concerns about the local water and soil and generally set the population on "pins and needles," in the words of the Port St. Lucie mayor.
At first, the mothers' effort seemed to stall as community leaders tried to stave off panic over a highly questionable public health threat.
But now the Florida Department of Health is launching a major investigation into the potential cancer cluster. And the federal Environmental Protection Agency mounted an investigation in September into an extraordinary rise in some childhood cancers nationwide.
"All of a sudden, we weren't just a bunch of stupid housewives with nothing better to do," said Marge McIntyre, one of the mothers who heads Suffer the Children, the Port St. Lucie group of cancer victims' families.
"Here was the government and health experts saying there was something out there, that more and more children are getting cancer and nobody knows why."
Since 1981, about 29 St. Lucie County children have been diagnosed with relatively rare brain cancers -- nearly three times the rate that would occur normally, local health officials said.
For families, it has been a devastating ordeal. The diagnoses came after lengthy illnesses that first were labeled flus, ulcers and other less dire ailments. The children go blind, experience chronic vomiting, suffer strokes, and in many cases, die.
Those who survive face brain damage, stunted growth, and secondary cancers later in life, usually as a result of radiation and chemical therapies.
But childhood cancer certainly is not unique to Port St. Lucie. In fact, the rate of cancer among children nationwide has been rising steadily since the early 1970s. About 8,000 new cases of cancer, the most common form of fatal childhood disease, are being diagnosed every year.
Put another way, a newborn child in the United States faces about a 1 in 600 risk of having cancer by age 10.
The reasons for the increases remain unclear, but experts suspect that it might have something to do with the huge number of untested chemicals to which children have been exposed.
Nationally, the rate of brain cancers of the type afflicting children in Port St. Lucie have increased by nearly 40 percent from 1973 to 1994.
Other cancers such as lymphoblastic leukemia have increased 27 percent in boys and girls from 1973 to 1990, according to the National Cancer Institute.
Since 1990, the rate in boys has declined but it is rising in girls.
These two forms of cancer account for most of the disease in children.
Other forms of cancer, especially those afflicting bones and kidneys, also have risen.
The increases are big enough that more accurate diagnosis and reporting of the diseases are unlikely to be the principal explanation, experts said. The methods used to diagnose cancer in children have not changed for decades, despite improvements in treatment that are saving more victims' lives.
"The good news is that the death rate of children with cancer is down. There's a whole new set of treatments that have been working quite well," said Dr. Philip Landrigan, a pediatrician who directs the division of environmental medicine at the Mount Sinai School of Medicine in New York City and a senior adviser on children's health at the EPA.
"The bad news is that the number of cases has been increasing over the last three decades," Landrigan said. "The increase is real; we just don't know what's causing it. I don't want to overstate the case, but I'd say there's a strong probability something in the environment is a factor."
A possible culprit, Landrigan said, could be substances among the estimated 75,000 new synthetic chemicals introduced in the past half century, including car emissions and pesticides in foods, homes and drinking water.
The combined effect of these substances might have particular threats for fetuses and children, whose immune systems and organs are still developing.
"You're talking about 15,000 chemicals in common use around the country, and only about half of them that have ever been tested," Landrigan said. "The real issue is that we are exposing children every day to chemicals that we've never tested for hazardous effects, which is simply criminal in my view."
In Port St. Lucie, parents began organizing after one mother, Juliann Freitas, began compiling a list of adolescent cancer victims in February. Her 4-year-old son had died from a cancerous brain tumor diagnosed just several months earlier.
Freitas found 19 cases and alerted the local media and other parents, who found more. Most were neuroblastomas and gliomas, a type of cancer rare enough that only 3.5 cases should have been found in the county of 175,000 people.