The cancers, however, are generally rare and the study cannot say one condition causes the other -- just that there is a link.

The finding "does sort of point to a global relationship to whatever is driving birth defects and what is driving childhood cancers," said Susan Carozza, a cancer researcher at Oregon State University in Corvallis.

Carozza and her colleagues linked several databases from Texas to identify the number of children born in the state between 1996 and 2005, the number born with birth defects and those who developed cancer.

There were over three million births in Texas during that 10-year period, and about four percent -- approximately 116,000 -- of those babies had at least one birth defect, such as Down syndrome and cleft palates.

Of all the Texas kids, about 2,350 -- or .08 percent -- developed cancer during the study period. Of those, 239 had been born with a birth defect.

The researchers calculated that children born with birth defects were three times more likely to develop a childhood cancer than those without birth defects.

Leukemias, eye and soft-tissue cancers and cancers of the ovaries and testis all seemed to be more common in kids who had birth defects, except those with a musculoskeletal deformity.

When the researchers took into account the already well-established link between leukemia and Down syndrome, the association between birth defects and other childhood cancers still remained.

"We had the same results -- the same pattern," said Carozza, whose study is published in the American Journal of Epidemiology.

Carozza and her colleagues also found that among children with birth defects, those not yet one year old had the highest chance of being diagnosed with cancer.

Dr. Sonia Partap, who has researched connections between birth defects and brain tumors, told Reuters Health in an email that it's important for parents and doctors caring for children with birth defects to know that childhood cancer is rare.

"This research is exciting in providing clues for the genetic links of childhood cancer which can perhaps in the future lead to new and better therapies," said Partap, of Stanford University and Lucile Packard Children's Hospital in Palo Alto, California.

As to why the link exists, Carozza said there could be a number of explanations. She said kids' genetics and environment may play a role, along with changes in how a person's internal organs are structured or lifestyle differences in children who were or weren't born with birth defects.

Unfortunately, according to Carozza, prevention techniques currently don't exist for childhood cancers.

"From the cancer side, there's no good screening. There is no parallel to a mammogram. It just doesn't exist for childhood cancer now," she said.

Partap, who was not involved with the new work, told Reuters Health that it's important for all parents to engage in proper well-child care with their pediatricians as recommended.

SOURCE: bit.ly/ImVMal American Journal of Epidemiology, online April 24, 2012.

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