FDG-PET is superior to gallium scintigraphy in staging and more sensitive in the follow-up of patients with de novo Hodgkin lymphoma: a blinded comparison

Abstract

Accurate staging of Hodgkin lymphoma (HD) allows for minimization of therapy and reduction of long-term toxicities. The present study prospectively compares FDG-PET with gallium/SPECT scintigraphy at time of diagnosis and in follow-up of 36 patients with HD. Prior to therapy, whole body FDG-PET and gallium/SPECT were performed. Follow-up scans were obtained after 3 cycles of chemotherapy (n = 22), and at the end of chemotherapy (n = 32). Two nuclear medicine physicians independently interpreted scans in blinded and random order and a consensus was obtained. Baseline scans revealed a greater number of supradiaphragmatic disease sites detected by PET, and 5 patients had splenic involvement on PET not noted by gallium (P = 0.05); 3 patients were upstaged on PET. Midway through therapy, 5 patients had positive PET (4 of whom relapsed), and 3 had positive gallium (1 relapsed). At conclusion of chemotherapy, 8 patients had a positive PET (4 relapsed) and 3 had a positive gallium (2 relapsed). In conclusion, diagnostic PET and gallium are largely concordant, with the exception of unique detection of splenic disease by PET. However, more patients have persistently positive PET at the end of chemotherapy compared with gallium (P = 0.04), although only half of these patients have relapsed.