Role of 18FDG-PET/CT in detecting relapse during follow-up of patients with Hodgkin’s lymphoma

Abstract

The role of 18 FDG-PET/CT during follow-up of patients affected by Hodgkin's lymphoma (HL) in complete remission after treatment is not fully elucidated, since a wide use of 18 F fluorodeoxyglucose positron emission tomography/computed tomography ( 18 FDG-PET/CT) in this setting could be limited by a relative high rate of false-positive results. Herein, we summarize a retrospective analysis of 27 patients with Hodgkin's lymphoma in complete remission after the first-line (n=20) or salvage (n=7) therapy receiving serial 18 FDG-PET/CT scans during follow-up. Out of 165 scans, 13 were suspected for relapse, which was confirmed in seven patients. All relapses were correctly identified by 18 FDG-PET/CT positivity, with a 100% sensitivity; false-positive rate was 46% and negative predictive value was 100%. True-positive findings were mostly associated with multiple sites, subdiaphragmatic involvement, and/or previous sites of disease. According to our results, we conclude that performing routine PET/CT scan during follow-up of those patients who are at high risk of relapse would be advisable, although caution must be adopted when interpreting PET/CT results due to the relatively high rate of false-positive findings. If FDG abnormal uptake is present at multiple nodal sites, subdiaphragmatic lymph nodes, or previous sites of disease, histological verification of PET abnormal findings is warranted.

Baseline and ongoing PET-derived factors predict detrimental effect or potential utility of 18F-FDG PET/CT (FDG-PET/CT) performed for surveillance in asymptomatic lymphoma patients in first remission

“…Another relevant issue related to the use of FDG-PET for relapse screening is the high prevalence of FP [26,27]. Besides affecting cost-effectiveness of PETsv, these findings are a source of anxiety and potentially further radiation exposure.…”

Positron Emission Tomographic Scans in Lymphoma: Convention and Controversy

“…However, imaging-detected relapse was not associated with improved survival. 53 An important issue related to the use of FDG-PET to screen for relapse is the high number of false-positive results 54 and the expense. 55 Furthermore, repeated PET scans increase the radiation exposure and thereby increase the risk for malignancy.…”

Reactive Tonsillar Enlargement Showing Strong 18F-Fdg Uptake During the Follow-Up of Follicular Lymphoma

“…18 F-FDG accumulation in the major salivary glands, spinal cord, and vocal cords is variable; whereas in the inferior concha, thyroid gland, and tongue is typically minimal [4]. In lymphoma patients, unfortunately, false-positive results are possible, because an infection, inflammation, hypermetabolic brown fat surrounding lymph nodes or reactive process producing strong 18 F-FDG uptake might be present [2,[5][6][7][8]. In these cases, and not uncommonly after chemotherapy, reactive enlargement of the lymph nodes, tonsils, and thymus gland can be detected [8][9][10][11][12].…”