Baseline total lesion glycolysis by positron emission tomography/ computed tomography as a best prognostic parameter for patients with primary thyroid lymphoma

Objectives To analyze the prognostic significances of total lesion glycolysis (TLG), metabolic tumor burden (MTV), and maximum standardized uptake value (SUV_max) in patients with primary thyroid lymphoma (PTL).

Methods Seventeen patients with PTL were histologically diagnosed in 1141 lymphoma patients. Baseline¹⁸F-FDG PET/CT scan was performed before therapy. TLGs, MTVs, and SUVs were calculated with the margin thresholds as 42% or 50% of SUV_max. Clinical outcomes were compared between metabolic parameters and prognostic factors.

Results Of nine quantitative parameters, only TLG50 of the whole body (TLG50_whole) was significantly associated with treatment outcomes (P<0.05). High TLG50_whole have been related with adverse prognostic factors (2-year PFS of 60±22 % versus 100 %, P=0.027; and 2-year OS of 53±25 % versus 100 %, P=0.023). SUV_max, MTVs, and clinical factors had no correlate with outcomes in PTL patients (P>0.05).

Conclusions Our preliminary results indicated the baseline TLG50_whole might help predicting the outcomes of PTL patients.