Predictive value of pretreatment positron emission tomography/computed tomography in patients with newly diagnosed extranodal natural killer/T-cell lymphoma

The role of ¹⁸Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in extranodal natural killer/T-cell lymphoma (ENKL) is not well established. This study aimed to investigate the prognostic role of the pretreatment maximum standardized uptake value (SUV_max) on PET/CT in patients with newly diagnosed ENKL. Among 364 consecutive patients with newly diagnosed ENKL, 81 patients were included and reviewed. The impact of SUV_max on survival and the relationship between SUV_max and other clinicopathological parameters were analyzed. The median SUV_max was 14.6 (range 2.0–45.4). The optimal cutoff value of SUV_max to predict overall survival (OS) was 15. Patients with high SUV_max (SUVmax >15) were associated with bulky disease (P < 0.001), local invasion (P = 0.030), high score of Korean Prognostic Index (KPI, P = 0.046), resistance to primary treatment (P = 0.014), poor OS (P < 0.001), and unfavorable progression-free survival (P < 0.001). With a median follow-up of 25.0 months, the median OS was 63.0 months (range 2.0–99.0 months). Multivariate analyses revealed the following independent prognostic factors for OS: age >60 years (P = 0.001), stage III–IV (P = 0.023), SUV_max >15 (P = 0.020), and bulky disease (>5 cm) (P = 0.002). By using the SUV_max, patients in most subgroups stratified by the KPI or the International Prognostic Index (IPI) were further discriminated in OS with significant statistical difference. Our results suggest the pretreatment SUV_max is predictive of prognosis in patients with newly diagnosed ENKL. The SUV_max may provide additional prognostic information for IPI and KPI.