Determining the extent and stage of disease in patients with newly diagnosed non-Hodgkin's lymphoma using 18F-FDG-PET/CT.

Positron emission tomography (PET) using 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) combined with computed tomography (CT) represents a three-dimensional imaging method suitable for staging in patients with non-Hodgkin's lymphomas (NHLs). The aim of our prospective multicenter study was to assess the value of initial PET/CT as compared with CT and PET alone for determining the stage and extent of the disease. A total of 122 patients with newly diagnosed NHL were examined using PET/CT. Four patients with resected lymphoma lesion and negative PET/CT were therefore excluded from the study. Of the remaining 118 cases, a total of 117 (99%) were described as 18F-FDG-avid. When compared with PET/CT, CT and PET showed very good sensitivity of lymph node imaging (97% and 100%, respectively); the specificity, however, was significantly lower (66.7% and 94.4%, respectively; p=0.0001). When detecting organ lesions, the sensitivity of CT and PET was lower than that of PET/CT (92.5% and 96.3%, respectively; p=0.0001); specificity was significantly decreased in CT and a little lower in PET (59.5% and 91.9%; p=0.0001). When compared with CT alone, PET/CT changed staging of the disease in 11 patients (9%) and was able to detect a total of 82 discrepancies in 67 of the 117 patients (57%). In conclusion, PET/CT is a new standard in imaging the involvement of lymph nodes and extranodal organs in NHL patients regardless of their histopathological types. Both sensitivity and specificity of the examination are higher than those of CT as well as PET alone.

FDG-PET for assessment of early treatment response after four cycles of chemotherapy in patients with advanced-stage Hodgkin's lymphoma has a high negative predictive value.

BACKGROUND: As positron emission tomography (PET) seems to be a powerful prognostic marker in the treatment of Hodgkin's lymphoma (HL), we analysed the prognostic value of PET after four cycles of combination therapy with bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisone (BEACOPP) in patients with advanced-stage HL. PATIENTS AND METHODS: From January 2004 to March 2007, 50 patients with newly diagnosed HL in clinical stages IIB with large mediastinal mass or extranodal disease, III and IV were treated according to the HD15 protocol of the German Hodgkin Study Group. All patients received a PET scan after four cycles of BEACOPP (PET-4). RESULTS: Of the overall group, 14 of 50 patients had a positive PET-4 while 36 had a negative PET-4. At a median observation time of 25 months, 2 of the 14 patients with a positive PET-4 had progressed or relapsed, while there was no progression or relapse in PET-4-negative patients. CONCLUSION: Our results indicate a very good negative predictive value of PET-4 in advanced-stage HL patients treated with BEACOPP.