RENO -- State health officials are monitoring a surge in a rare form of childhood cancer in Nevada, with at least five cases reported over the past two years, the Reno Gazette-Journal reported Monday.
The cancer known as RMS, or rhadbdomyosarcoma, attacks muscles. In addition to the five confirmed cases, the newspaper located a sixth case that apparently has gone unreported.
Officials for the Nevada Center for Health and Data Research said they are watching the situation to see if the disease is on the upswing or whether the numbers will average out in the next few years.
"It's hard to make conclusions from so few cases, but if we get more cases well be in trouble," said Wei Yang, state bio-statistician and director of the center.
The cases of rhabdomyosarcoma also have been showing up in towns nationwide that have childhood leukemia clusters, including Fallon. In that community, 16 youngsters have been diagnosed with childhood leukemia since 1997. One case of RMS was diagnosed there in January.
In all, there were 16 reported cases in Nevada of the rare cancer among people under 18 between 1995 and 2001. Of those, at least five attacking children under 14 were reported in the last two years.
"Three cases in children under age 14 is higher than what we would expect to see in two years, but averaging out the seven years (1995 to 2001) we are still within the normal range for that age group," Yang said.
The newspaper last week documented a sixth case of rhabdomyosarcoma in a child under 14 that doesn't show up in the state statistics. In addition, the paper confirmed a case in Fallon, diagnosed early this year. That case does not show up in state statistics either because the Nevada Cancer Registry takes about two years to complete its count.
Yang said even with two extra cases, the states numbers still are within expected levels. He said he did not know why the case from 2000 didn't show up in the cancer registry.
Robert Johnson's son, Lane, was born in 2000 with the disease, but state statistics do not include his case.
"My son is apparently invisible to the Nevada Cancer Registry," said Johnson of Sun Valley. He said the discrepancy shows more attention needs to be paid to tracking cancers.
Lane, now 2, began showing symptoms of RMS while still in the womb and has recovered from the disease. His diagnosis was made at the University of California, Davis, Medical Center in December 2000.
"My son, and a child from Palomino Valley, and a child from Spanish Springs were all diagnosed with rhabdomyosarcoma within the last three months of 2000," Johnson said.
State officials said Washoe County cases diagnosed in California in 2000, while not available to Nevada officials at the time, have since been added to the Nevada registry. But they could not explain why the registry shows only two cases in Washoe Country for that year, instead of three.
Including the Fallon boy diagnosed in January, there's been a surge of four cases in northern Nevada in the last 15 months.
"It's strange to have four cases in a 65-mile radius with a small population within such a short period of time," Johnson said. "And those are just the ones we know about."
In Nevada, the expected rate of RMS in children under age 14 is about 1.81 cases per year, state health officials said.
Nationally, the incidence rate for rhabdomyosarcoma hasn't changed over the last few decades, according to the American Cancer Society. The society said about 250 new cases of childhood RMS are diagnosed each year, and the disease accounts for about 3.4 percent of all childhood cancers.
"Four cases for every million children is in the right ballpark for the expected numbers of rhabdomyosarcoma," said Dr. Doug Taylor, a pediatric hematologist-oncologist at UC-Davis Medical Center. "Whether little groupings of rare cancers define a cluster or not is a matter for statisticians. It's a harder thing to determine than it would initially appear."
Cancer doctors and researchers said all childhood cancer is rare and RMS is the rarest of the rare, so with so few cases its hard to tell if there's a problem. But they said any situation that seems out of the ordinary suggests further study is needed.
"Rhabdo is unusual, so seeing more than the expected number of cases could be a statistical blip, or it could be way out of line," said Dr. Michael Link, chief of hematology, oncology and stem cell transplantation at Stanford University School of Medicine in Stanford, Calif.