Common infections, such as cold and influenza, may precipitate some cases of certain childhood cancers, according to a report by British and Scottish researchers.
The findings, published in the December issue of the European Journal of Cancer, are based on an analysis of 44 years of British pediatric cancer data and their discoveries that both leukemia and brain tumors — leading cancers in children — occurred in clusters. This suggests that outbreaks of infections contribute to those malignancies, researchers said.
“We found that place of birth was particularly significant, which suggests that an infection in a mother while she is carrying her baby or in a child’s early years could be a trigger factor for the cancer,” said Dr. Richard McNally of the Royal Victoria Infirmary in Newcastle, England, and lead author of the report.
“These could be minor, common illnesses, such as a cold, mild flu or a respiratory infection,” he said.
In their report, Dr. McNally and his colleagues said that after reviewing several thousand cancer cases among children 14 and younger who were diagnosed between 1954 and 1998, their results are “consistent with common, possibly infectious etiological mechanisms for childhood leukemia (particularly acute lymphoblastic leukemia, or ALL) and central nervous system tumors (particularly astrocytoma).
“We would speculate that around 10 percent of the astrocytoma cases and around 3 percent of the ALL cases may have arisen in this manner,” the researchers concluded.
But Dr. David Ascher, chairman of the Department of Pediatrics and a pediatric infectious disease specialist at Inova Fairfax Hospital for Children, called the statistical associations Dr. McNally found in the study “small.”
“For a pregnant woman to become concerned about getting a cold in the dead of winter” and having a baby that could develop leukemia or brain cancer “may be unwarranted,” he said.
But the European researchers said their findings build on the results of prior studies that have used “space-time clustering” of childhood cancers, which have suggested that leukemia and brain tumors in children may be linked to infections.
They stressed that their study was the first to “systematically examine cross-clustering between cases from different diagnostic groups.”
Cross-clustering involves the clustering of different diseases in a certain location or time.
Leukemia is the most common childhood cancer, accounting for a third of all cases in the United States, according to the National Cancer Institute. Nearly 20 percent are brain and other nervous system tumors, NCI says. It puts the five-year survival rate for childhood leukemia at 85 percent.
On average, two-thirds of children with tumors of the brain or other parts of the nervous system survive five or more years, NCI says.