Infant Cancer Screening No Panacea
Tests find tumors, but don't cut death rate
WEDNESDAY, April 3, 2002 (HealthDayNews) -- Routine screening for some of the most common forms of solid tumors in babies might catch cancers early, but it doesn't seem to reduce the risk of death from the disease.
The tumors, called neuroblastomas, occur in nerve roots and usually lead to an increase in urine of chemicals known as catecholamines, which tip off doctors before symptoms appear. While it seemed intuitive that looking for these markers would lead to early detection of the cancer, and thus save lives, new research from North America and Germany says that's not the case.
Since widespread testing of all infants would be enormously expensive, experts say, the weak results don't justify the practice. In fact, the test may lead to more harm than good if children with less aggressive forms of the tumors suffer harm from treatment. Both studies appear in tomorrow's issue of the New England Journal of Medicine.
Neuroblastomas occur in one in 7,000 children in the United States each year, making up as much as 10 percent of all childhood cancers and half of those found in infants.
Japan has led the charge for neuroblastoma screening, which is now mandatory in that country. However, doctors in the United States, Canada and Europe have had reservations about the test and, as the latest results show, for good reason.
In the first study, researchers in the United States and Canada analyzed the impact of neuroblastoma screening among all infants born in Quebec between 1989 and 1994. During that time, nearly 440,000 babies received the test, first at three weeks of age and again at six months.
Yet, the death rate from the brain tumors was roughly the same in Quebec as it was among unscreened groups of children in other parts of North America, including the United States, the researchers found.
"It picks up the tumors that seem to be destined in general to do well, and it doesn't pick up the tumors that seem to be the bad actors," says Dr. William G. Woods, a childhood cancer expert at Emory University in Atlanta and lead author of the study.
The second study, from scientists in Germany, turned up similar results when the test was performed on year-old babies. The researchers, led by Dr. Freimut Schilling of the Klinikum Stuttgart, say screening might have led to the early detection of 11 of 149 tumors, or 7 percent, that occurred in the nearly 1.5 million tested children.
Yet, that "small potential benefit" was outweighed by the 99 children who had neuroblastomas with favorable prognoses and who might have been harmed by treatment, they say. Three with localized tumors ultimately died of treatment-related illness.
Intriguingly, Woods says, it now appears that many neuroblastomas go away on their own. "They look cancerous, they look like they should act that way, but for some reason" they simply decide to resolve themselves.
Dr. George Cunningham, chief of the genetic disease branch at the California Department of Health Services, argues the latest findings underscore the need for firm evidence before implementing screening tests.
"Sometimes we have to admit that we don't have the technology to effectively or efficiently screen" for a disease, Cunningham says. "We do have to be concerned about our resources. We want the public to get its money's worth."
Cunningham, author of an editorial accompanying the journal article, says government and private research spending on biotechnology, and the breakthroughs those dollars produce, is outstripping the ability of states to provide screening to their citizens.
"No one's thinking about how to translate these tests into ordinary clinical care, and make them accessible to everybody," he says.
What To Do
To find out more about infant screening tests, check out KidsHealth.