Incidence of childhood leukemia up in Fallon

A recently discovered cluster of pediatric leukemia cases in Fallon has officials worried.

Doctors have diagnosed seven Fallon children with acute lymphocytic leukemia: one in April of 1999, and six from March to July of 2000.

Epidemiologists say the numbers are a dramatic increase from what might be normally expected.

"When we looked at cancer registry data of all pediatric acute lymphocytic leukemia in all 15 rural counties over time, there might be one case, or four at the most (in a year).

"So to get six in one year from one county is surprising. We also looked at the cumulative number of reported cases," said Nevada State epidemiologist Randall Todd, noting that records have been kept since 1979, and only one case of childhood leukemia had been reported in Fallon before 1999.

"Sometimes there is a cluster of childhood leukemia in terms of geography and time, and no one knows why," Todd said. "Sometimes it is an expected environmental exposure, but in most cases we don't find that. We don't know what the outcome of this investigation will be, and the probability (of finding a cause) isn't that great, but we would be remiss if we didn't try."

While some may be quick to point a finger at Fallon's high arsenic levels, Todd said there is no real evidence indicating arsenic is the culprit at this point.

"In preparing to do this investigation, we reviewed medical literature, and we didn't find anything that said arsenic in drinking water caused leukemia," Todd said, noting that the arsenic problem has been endemic for years, while the increase leukemia is fairly recent.

"It may be statistical fluke. We're doing a detailed assessment of residential history and we may learn some haven't lived in Fallon all that long," he said.

The aquifer beneath Fallon contains arsenic at twice the maximum level allowed by safe drinking water laws, an issue known for some three decades.

Jon Merkle, an environmental scientist in the Environmental Protection Agency's San Francisco office, has called it ''the Mount Everest of arsenic situations.''

Some federal housing programs have cut off aid to the area, and the EPA is threatening to fine Fallon $27,500 a day until the city complies with the agency's standard.

The EPA also has proposed a tenfold reduction in the federal arsenic standard - from 50 parts per billion to 5 ppb - under the Safe Drinking Water Act. Some Fallon water has tested at 100 ppb.

To find out more about the leukemia cases, Todd said lengthy interviews are being conducted at the families' convenience, but schedules are hectic because families are traveling out of town for their children's treatments.

Once the data is accumulated, it will take time to analyze. Todd said there are several subtypes of acute lymphocytic leukemia, and it will be interesting to see if these children harbor the same subtype.

"Any cancer is a serious disease," Todd said. "My understanding is that many respond well to treatment. It's a tragic situation - I don't know if we will find anything, but it is important, so we will try."

Glossary: Childhood acute lymphocytic leukemia (also called acute lymphoblastic leukemia or ALL) is a disease in which too many underdeveloped infection-fighting white blood cells, called lymphocytes, are found in a child's blood and bone marrow. ALL is the most common form of leukemia in children, and the most common kind of childhood cancer.

Source: The National Cancer Institute