Infant screening for neuroblastoma, one of the most common forms of
solid tumors in young children, fails to detect the most severe form of
the disease, according to a group of international researchers led by University
of Minnesota faculty. After screening nearly 500,000 Canadian infants for
neuroblastoma, the group found that screening did not detect the most severe
neuroblastomas even though it found twice as many cancers as had been expected.
The researchers conclude that, if left to run their course, some neuroblastomas
detected by screening in infancy either go away or fail to progress. Results
of the Quebec Neuroblastoma Screening Project appear in the December 21,
1996, issue of The Lancet.
"Widespread infant screening for neuroblastoma does not save lives
and could subject infants to unnecessary cancer treatments," said
Mendel Tuchman, one of three principal investigators of the study. No such
routine screening programs are currently in place in the United States,
added Dr. Tuchman, who is professor of pediatrics and a member of the University
of Minnesota Cancer Center. Other principal investigators were William
Woods, professor of pediatrics and director of the South Carolina Cancer
Center at the University of South Carolina; and Bernard Lemieux, professor
of pediatrics at the University of Sherbrooke in Quebec. Leslie Robison,
holder of the Cancer Center Children's Cancer Research Fund chair in pediatric
cancer at the University of Minnesota; and Russell Luepker, professor and
head of the division of epidemiology in the University of Minnesota School
of Public Health, also were involved in the study.
"When the disease develops before the child is a year old, it is
often successfully treated," said Tuchman, whose laboratory developed
and performed the screening test. "After that age, it could evolve
rapidly into an advanced stage disease with a very high mortality. It is
extremely unfortunate that infant screening does not detect the severe
neuroblastomas that develop in older infants."
Two Distinct Types of Neuroblastoma
Researchers now believe that there are at least two distinct types of
neuroblastoma. One that appears at birth or shortly thereafter may resolve
spontaneously without leaving any trace of the disease. A more advanced
form appears in older infants and carries a high mortality. One in 7,000
children is diagnosed with neuroblastoma, making it one of the most common
malignant tumors in young children. In 90% of cases, the disease affects
those under 5 years of age.
"While screening for cancer has great appeal, these results demonstrate
the importance of large-scale studies to make sure we don't do more harm
than good and end up wasting millons of dollars," said Robison. Prior
to the study, many people had advocated for widespread infant screening
in the United States, based on preliminary reports from programs in Japan.
The $6.6 million Quebec Neuroblastoma Screening Project was funded by
the National Cancer Institute (NCI). The NCI grant was based on the results
of a pilot study in the Twin Cities funded by the American Cancer Society.
Children born between 1989 and 1994 in the Province of Quebec were screened
for neuroblastoma. Quebec was chosen for the study because it had an established
program to screen for metabolic defects at the age of 3 weeks. Parents
submitted urine samples from their children at the ages of 3 weeks and
6 months. Researchers analyzed samples from 425,816 3-week-olds (91% of
those eligible). At 6 months of age, samples from 349,706 (75%) of those
children were again analyzed. The 118 detected neuroblastoma cases were
more than twice the 54 expected, when compared with newborns in Ontario
and Minnesota, where screening was not performed.