Clinical significance of 18F-FDG uptake by primary sites in patients with diffuse large B cell lymphoma in the head and neck: a pilot study

Objective  This pilot study was launched to explore the utility of positron emission tomography scans, at the time of diagnosis, for clinical outcomes in patients with primary extranodal non-Hodgkin’s lymphoma (PENHL) in the head and neck, retrospectively. Methods  Twenty-two patients with a diffuse large B cell lymphoma (DLBCL) among those with a PENHL were included. We retrospectively evaluated the clinical outcomes of patients according to the maximum standardized ¹⁸F-fluoro-2-deoxy-glucose (¹⁸F-FDG) uptake value of the primary lesion (SUV_p). The SUV_p was initially analyzed as a continuous variable. The cut-offvalue of SUV_p was obtained from receiver-operating characteristic analysis to predict event-free survival. Using this value, patients were divided into those with a low and high SUV. Results  Seventeen patients (59%) were men and the median age was 50 years. Most primary sites were in Waldeyer’s ring (73%). The SUV_p ranged from 3.3 to 23.7. The international prognostic index (IPI < 2 vs. ≥ 2) was associated with the SUV_p (P = 0.014). Patients with low SUV_p showed favorable survival (P = 0.015). After IPI scores were stratified, the survival difference remained significant (P = 0.029). Conclusions  The results of this pilot investigation indicate that ¹⁸F-FDG uptake of the primary lesion may be related with survival outcomes in patients with extranodal DLBCL in the head and neck. Further studies are needed to confirm and extend these results. I.I. Na and G.J. Cheon contributed equally to this work.