Two new studies raise questions about a possible link between childhood cancer and light therapy for newborn jaundice.
These questions should alert clinicians to exercise caution in prescribing the treatment for infants whose jaundice is likely to resolve on its own.
However, the suggestion of a link should not deter use of the treatment in babies who otherwise would be at risk of brain damage or hearing loss.
Although the findings were inconclusive, the research represents an important and novel approach using “big data” to determine whether environmental factors play a role in the development of pediatric cancer.
Two studies examined an association between phototherapy and pediatric cancers.
The first study analyzed data from five million infants born in California hospitals between 1998 and 2007. The study used administrative data that linked the billing code for phototherapy and the diagnosis code of childhood cancer. The strongest association is a 1.6 fold increased risk of acute myeloid leukemia.
The second study analyzed data from 500,000 children born in the Kaiser Permanente Northern California healthcare system between 1995 and 2011. The associations between phototherapy and childhood cancer were not statistically significant, but and association with acute myeloid leukemia was again observed.
These studies come at a time when the number of infants receiving phototherapy is increasing partially due to the availability of light therapy units that can be used in the home.
In both studies, the associations were stronger and statistically significant among children with Down syndrome. Children with Down syndrome are already known to be at an increased risk of leukemia.
Studying childhood cancer is difficult because it is such a rare disease. To study childhood cancer, a researcher needs to find a way to study large populations. These two studies found a way to do just that. However, even in these studies of huge populations, the number of children who actually develop cancer remains quite small.
These studies suggest that phototherapy may not be harmless and that the risks as well as the benefits need to be weighed before flipping the switch.