Combining CT and PET Scans in Lymphoma Staging

The use of a combined PET (positron emission tomography) and CT (computed tomography) machine for use in initial staging of lymphoma changed treatment decisions in roughly one-quarter of patients with non-Hodgkin’s lymphoma (NHL) and roughly one-third of patients with Hodgkin’s disease (HD) in a recent study in the Annals of Oncology. Changes in staging and treatment were most likely for patients with stage I or stage II disease based on the CT.



To overcome the limitations of CT and PET used individually, an integrated (combined) PET/CT system has been developed. In order to determine whether use of PET/CT results in different staging information and treatment decisions than use of CT alone, researchers in Israel conducted a study among 103 patients with newly diagnosed lymphoma. Sixty-eight patients had NHL and 35 had HD. Use of PET/CT changed treatment decisions. Among NHL patients, use of PET/CT after CT alone changed treatment decisions for roughly one quarter of patients. Among HD patients, use of PET/CT after CT alone changed treatment decisions for 32%–45% of patients. In contrast, compared to treatment decisions based on PET/CT alone, the addition of CT changed treatment decisions for only a small number of subjects.



The researchers note that PET/CT may become the standard approach for initial staging of lymphoma. In the meantime, following an initial diagnostic CT by PET/CT appears to be most appropriate for patients with early-stage disease.