Malik Juweid, M.D., associate professor of radiology at the University of Iowa showed in a study that adding FDG-PET to the standard computer tomography (CT)-based assessment criteria made the predictions of treatment outcome much more accurate for aggressive non-Hodgkin's lymphoma. Based on this study, the new internationally accepted criteria will include PET as an essential part of the assessment and management of lymphoma.

"Basically, about half of patients were called partial or incomplete responders because CT found a residual mass after treatment despite lack of any other evidence of disease," Juweid said. "However, PET showed that the residual mass was scar tissue rather than viable tumor in more than half of these patients. These patients were, therefore, reassigned as complete responders, and we found that they did just as well as patients who had been given the 'all clear' from the CT scan."

The study showed that if PET is negative, patients can be safely observed without biopsy, and patients and physicians can be much more confidant that the patient will remain progression free. However, if a PET scan is positive and the findings are confirmed by a biopsy, patients can move more quickly to necessary salvage therapy.

PET can also serve as a tool to enable physicians to monitor tumor response during treatment and potentially to tailor the treatment based on the PET results. And when a PET scan shows the treatment is not working, stopping chemotherapy would spare the patient from toxic side effects and might also prevent a tumor from becoming resistant to chemotherapy before a more potent treatment can be tried. Alternative treatment options would be pursued for these patients.; Quelle: University of Iowa