After cancer, kids get too many CT scans

Children who have completed treatment for Hodgkin's lymphoma, a cancer of the lymph tissue, are routinely given follow-up CT scans that don't lead to better chances of surviving a relapse, according to a new study.

Given the expense and potential hazards of exposing kids to radiation from such scans, some physicians are advocating for fewer routine screens.

"We don't have any evidence that (doing these scans) is a good idea," said Dr. James Armitage, a professor at the University of Nebraska Medical Center, who was not involved in the study.

He added that the scans are moneymakers for those doing them, but increase the risk of cancer in patients—particularly children.

Hodgkin's lymphoma is a cancer that starts in the white blood cells, which are part of the body's immune system. According to the National Cancer Institute, 850 to 900 children are diagnosed with Hodgkin's lymphoma each year, and about 90 percent of kids with the cancer survive.

After patients finish lymphoma therapy, doctors usually follow up with at least one CT, or computed tomography, scan each year for several years. The scans use a high dose of x-rays to search for signs of cancer.

"It's not necessarily a trivial exposure to radiation," said Armitage.

One recent study found that children who received two or three CT scans of the head were three times as likely to later develop brain cancer than kids who never had any scans, although the risk remained tiny.

CT scans are expensive, too. In an editorial accompanying the new report, in the Journal of Clinical Oncology, Armitage noted that at his center, a CT scan of the chest, abdomen and pelvis costs nearly $7,000.

"The concern was that those CT scans were not necessarily providing any additional value beyond what a good clinical exam or what a change in symptoms might have brought to light," said Dr. Stephan Voss, the lead author of the new study and a radiology professor at Boston Children's Hospital.

To determine whether routine scans in patients without symptoms might help save lives, Voss and his colleagues gathered medical information on 216 pediatric patients who received five follow-up CT scans over about three years.

The researchers found that 16 patients had a relapse of the cancer within the first year after treatment had ended.

Most of these cases were detected from symptoms or a physical exam, while two relapses were diagnosed by a routine CT scan.

Nine patients had a relapse after the first year, and four of them were diagnosed by a routine CT scan.

"If we looked at those patients," Voss said, "it didn't really make any difference whether the relapse was detected incidentally based on a CT scan or based on new symptoms. The majority of those patients did very well."

Voss said the results show that, a year or more beyond treatment, routine scans are not necessarily improving the likelihood that children will survive.

His practice has already changed its recommendations for new patients with Hodgkin's lymphoma, such that none of them should have a routine scan more than one year after treatment.

Doctors will still recommend that children receive CT scans at the end of treatment and six and 12 months later.

"We don't want to stop screening patients at a time when they are known to have a high risk of relapse," Voss said.

Armitage said it would be valuable to do a study to find out if there are some patients who do benefit from routine CT scans.

But, he added, "I think it's overwhelmingly clear that in most situations, they're not beneficial."