The Lugano Classification incorporating FDG-PET/CT in the staging and response assessment of lymphomas was published (JCO 2014). However, the concordance between the clinical stage assessed by FDG-PET/CT and that assessed by the conventional evaluation remains elusive.
Patients (pts) who were initially histopathologically diagnosed as having DLBCL at our institution from 2010 to 2012 were included. The clinical stage using only FDG-PET/CT was compared to that by the conventional evaluation based on CT, esophageogastroduodenal endoscopy (EGD) and bone marrow (BM) aspiration and/or biopsy.
A total of 98 pts were identified as subjects of this retrospective analysis with a median age of 64 years (range; 30-91). 11 pts (11%) resulted in upstaging through conventional evaluation plus FDG-PET/CT; 3 from stage I to IV, 6 from II to IV, 1 from II to III, and 1 from III to IV (Table 1). 3 pts (3%) resulted in downstaging; 1 from stage II to I, and 2 from IV to III. Bone or BM lesions were more frequently detected by FDG-PET/CT. BM examination detected 6 pts (6%) with BM lesions, while FDG-PET/CT detected 10 pts (10%). However, 2 pts (2%) of BM lesions went undetected by FDG-PET/CT. Compared with EGD, FDG-PET/CT seems to be less accurate in detecting gastric lesions. 19 pts (19%) had gastric lesions detected by the EGD but only 4 of them were positive by FDG-PET/CT. On the other hand, 3 pts had FDG-PET/CT positive colon lesions, which turned out to be adenocarcinoma with colonoscopic biopsy.
Our data suggests that FDG-PET/CT cannot completely take the place of conventional staging evaluation for DLBCL mainly because of low sensitivity of gastrointestinal lesions, although FDG-PET/CT is useful in the staging of DLBCL. Therefore, we still recommend EGD as one of the routine staging procedures of DLBCL, and also recommend colonoscopy when FDG-PET/CT positive.
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All authors have declared no conflicts of interest.