Impact of 18F-FDG PET/CT in Predicting Recurrence in Neurolymphomatosis

To clarify the prognostic value of 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in Neurolymphomatosis (NL), we retrospectively reviewed medical records of all NL patients who had undergone 18F-FDG PET/CT from 2007 to 2020 at Kameda Medical Center and Tokyo Medical and Dental University Hospital. The clinical data of patients were compared with 18F-FDG PET/CT findings of number of nerve lesions and presence of non-nerve extranodal lesions (ENL). Subsequently, we calculated recurrence-free survival (RFS) and overall survival (OS) using the Kaplan–Meier method. A total of 28 patients (mean age 70.1 years, range 44–87 years; 15 women) were included in the study and 7 patients (25.0%) relapsed NL. The number of nerve lesions detected by 18F-FDG PET/CT ranged from 1 to 5, with an average of 2.02. ENL was observed in 18 cases (64.3%). The comparison between the findings revealed that the more the lesions detected by 18F-FDG PET/CT, the higher the probability of recurrence (χ2 = 13.651, p = 0.0085) and there was significantly shorter RFS for the patients with 3 or more nerve lesions (p = 0.0059), whereas the presence of ENL was not significantly associated with any clinical findings. The present study revealed that the more nerve lesions detected by 18F-FDG PET/CT, the poorer the recurrence rate and RFS.