PET/CT improves evaluation of pediatric cancers

January 2, 2008

NEW YORK (Reuters Health) - In children with non-CNS malignancies, fluorodeoxyglucose (FDG) PET combined with CT in a single examination shows significantly better diagnostic performance than does conventional imaging, such as contrast CT or MRI, researchers report in the December issue of the Journal of Nuclear Medicine.

As Dr. Richard L. Wahl said in a statement, "PET/CT is useful in finding small tumors in small children and is a promising imaging tool in evaluating pediatric malignancies."

Dr. Wahl and colleagues at Johns Hopkins Medical Institutions, Baltimore, Maryland reviewed 151 FDG PET/CT studies that were performed in 55 children with non-CNS malignancies. Of these studies, 108 were accompanied by conventional imaging obtained within a month of PET/CT.

The team found that PET/CT produced accurate findings in 72 of 80 lesions in which there were discordant findings on conventional imaging.

The researchers also note that additional information was provided by PET/CT in more than one third of compared examinations.

In another study in the same issue of the journal, Dr. Hans U. Gerth of University Hospital Munster, Germany, and colleagues compared the outcome of 163 PET/CT studies to that of PET in 53 patients (median age, 16.5 years) with confirmed Ewing tumors.

A total of 609 lesions were detected by PET. However, 21% more (for a total of 733) were detected by PET/CT. Altogether, say the investigators, PET/CT was "significantly more accurate than PET alone for the detection and localization of lesions and improved staging of patients with Ewing tumor."

Dr. Noah Federman, author of an accompanying editorial, told Reuters Health that "overall, there is an increasing evidence base to support the use of combined FDG PET/CT in the management of pediatric cancer. This has been shown most convincingly in patients with Hodgkin and non-Hodgkin lymphoma and to a lesser extent in pediatric bone and soft tissue sarcomas."

However, added Dr. Federman of UCLA Mattel Children's Hospital, Los Angeles, "The role of PET/CT as an imaging modality in other pediatric malignancies has yet to be rigorously studied and may not provide any benefit."

Moreover, he concluded, "as the use of PET/CT increases in our management of these often devastating cancers, we must pay careful attention to the radiation doses that children receive, which are not inconsequential."