PET parameter is better than a visual read for Hodgkin's lymphoma

A reduction of the FDG maximum standardized uptake value is superior to visual analysis for the evaluation of treatment response in patients with Hodgkin's lymphoma, according to a study published online Feb. 24 in the Journal of Nuclear Medicine.

Cedric Rossi, MD, from the Hematologie Clinique, CHU Le Bocage in Dijon, France, and colleagues assessed the two means of gauging response after two cycles of chemotherapy. Researchers compared a five-point visual analysis with a more quantitative protocol focusing on falling maximum standardized uptake values from baseline to follow-up in this retrospective study.

“These encouraging results suggest the use of semiquantitative analysis in addition to visual analysis to interpret early PET findings for [Hodgkin’s lymphoma] patients, specifically for predicting with good confidence those patients who will have a poor outcome requiring alternative therapies.” Wrote Rossi et al. “Larger and prospective series are warranted to confirm these preliminary results.”

For this study, a total of 59 subjects were treated for Hodgkin’s lymphoma from 2007 to 2010 with four to eight cycles of chemotherapy. Of these, 14 patients went up to receive radiotherapy. All patients underwent PET imaging at baseline and after two cycles of chemotherapy. Patients with a maximum standardized uptake value greater than 71 percent were noted as “good responders.”

Results revealed that 46 patients, or 78 percent, achieved a negative second PET scan with visual interpretation, while seven of these had failed treatment for a negative predictive value of 85 percent. A total of 49 patients, or 83 percent, showed a maximum standardized uptake value greater than 71 percent. Of these, six patients had actually failed treatment. This gives the semi-quantitative PET parameter 88 percent negative predictive value. Maximum standardized uptake value showed significantly better predictive value, 70 percent, than the visual scale did, 46 percent.

It is important to note that a positive second scan was associated with lower four-year progression-free survival—45 percent, versus a negative second scan—for 81 percent progression-free survival.