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Changing Clinical Practice for the Better
New Study Suggests Reducing CT Imaging in Pediatric Cancer Patients With Initial Febrile Neutropenia

In a new study in the February issue of Pediatric Blood Cancer, CHORI clinical scientist Anurag K. Agrawal, MD, and his colleagues determined that using routine computed tomography (CT) in pediatric cancer patients to evaluate potential causes of infection during initial febrile neutropenia does not provide enough diagnostic value to outweigh the associated radiation exposure.

"Due to cancer therapies and the routine surveillance that is required, many of the patients are already getting a lot of CT scans and radiation, so we wanted to see in this study if we could determine when, and if, CT scans were of value in treating kids with febrile neutropenia," says Dr. Agrawal.

“We wanted to see in this study if we could determine when, and if, CT scans were of value in treating kids with febrile neutro-
penia.”


Febrile neutropenia, or FN, occurs in patients with compromised immune systems. In cancer patients, chemotherapy treatments reduce the normal number of cells that the body uses to fight infections, specifically bacteria-fighting cells called neutrophils.

"When patients have a very low neutrophil count, it indicates they are at higher risk of getting an infection," explains Dr. Agrawal. "FN occurs when kids get a fever at the same time their neutrophil count is low, and it suggests the potential for an active, serious infection."

When FN occurs, patients are generally hospitalized so that the type of infection can be determined and treated. But figuring out what kind of infection a patient might have is not necessarily that easy.

"In some kids, they have a short period of time with a fever, and then it resolves and they go home. In other kids, the fever persists longer and we are able to find a source for the infection, such as bacteria in the blood for example," Dr. Agrawal says. "In a large portion of kids, however, the fever continues with no known source."

In those cases, pediatric oncologists generally treat patients with empiric antibiotics and antifungals. In addition, with continued FN for five to seven days, it has become standard practice to perform CT images on the sinuses, chest, abdomen and pelvis to look for evidence of occult infections. However, the risk of radiation exposure in children, and children being treated for cancer in particular, has come under more scrutiny as cancer treatments have become more successful and cancer patients are living longer.
“Everyone has always proceeded from the concept of exposing patients to as little radiation as possible considering the long-term potential risks, but now we're finding more ways in which we can reduce the exposure.”
As the results of the new study show, reducing the use of CT scanning with initial FN may be a simple way for pediatric oncologists to reduce their patients' radiation exposure.

In the study, although there were positive findings in 18, 12, and 25 percent of initial CT scans of the chest, abdomen, and sinuses, these positive findings rarely resulted in changes in therapy. In fact, alteration in therapy at this stage was incredibly rare, only occurring in two of the initial scans or 0.8 percent of all the scans that were done.

Patients that were asymptomatic but were still scanned due to the length of their FN may have had positive findings on CT but due to the use of empiric antibiotics and antifungals, these findings were generally not significant, meaning they did not affect how the patient was treated for the FN.

"The study demonstrated that doing a full series of scans sinuses, chest, abdomen and pelvis did not have much utility in the setting of an initial episode of FN. Of all the scans, the chest seemed to be the one area that might still be of benefit. Still, eliminating the standard CT of the sinuses, abdomen, and pelvis at this stage would be a significant reduction in radiation for kids with prolonged FN," says Dr. Agrawal.

Dr. Agrawal is hopeful that the results of the study will help guide pediatric oncologists treating cancer patients from here on out.
“As our treatments have become better, we are having more and more patients who are surviving cancer.”
"We really have to think about longer term effects, and start looking at other things we do that impact long term survival, and radiation exposure definitely plays a role," says Dr. Agrawal.

"We undertook the study with the hopes of changing clinical practice and reducing radiation exposure. I think we've done a pretty good job of showing that CT scanning with initial FN is a place where we can do exactly that."
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Tuesday, May 17, 2011 8:19 AM

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