Pet/Ct Alone Versus Pet/Ct And Mri-Guided Therapy In Patients With Upper Aerodigestive Tract Natural Killer/T-Cell Lymphoma, Nasal Type: A Prospective Study.

7537 Background: Radiotherapy is extremely important in extranodal natural killer/T-cell lymphoma (ENKTL). [18F]-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is a routine pretreatment imaging technique used in ENKTL, while magnetic resonance imaging (MRI) plays a key role in head and neck (HN) cancer. The purpose of this study was to investigate the value of pretreatment HN-MRI and PET/CT-guided therapy in improving survival in upper aerodigestive tract ENKTL (UADT-ENKTL). Methods: We prospectively conducted a single center study on untreated patients with pathologically diagnosed UADT-ENKTL. Patients undergoing PET/CT with/without HN-MRI were decided by clinicians for staging and restaging. The patients were treated with L-asparaginase/Pegaspargase and non-anthracycline-based chemotherapy with intensity-modulated radiation therapy (IMRT). Results: We enrolled 171 patients (median age, 44 years; range, 18-75 years; 118 (69%) males) from April 2011 to March 2018. Overall, 71 patients underwent PET/CT and HN-MRI (PET/CT-MRI) and 100 patients underwent PET/CT alone. HN-MRI upgraded the clinical stages in 8 patients (8/71) undergoing PET/CT based on the Ann Arbor staging system and in 10 patients (10/71) based on the TNM staging system by detecting additional local lesions ( P=0.011 and P=0.019, respectively). With a median follow-up of 54 months, the 5-year overall survival (OS), local recurrence-free survival (LRFS) and progression-free survival (PFS) rates were 72.7%, 68.6% and 68.2%, respectively, for all patients. The 5-year LRFS rate was 100% in the PET/CT-MRI group and 64.3% in the PET/CT group ( P<0.001). Similarly, the 5-year OS and PFS were longer in the PET/CT-MRI group than in the PET/CT group (84.5% vs. 67.8% and 78.3% vs. 65.6%; P=0.04 and P=0.03, respectively). Conclusions: HN-MRI and PET/CT-guided therapy could assist in decreasing local recurrence, which improved prognosis in UADT-ENKTL patients. Therefore, HN-MRI and PET/CT should be incorporated into routine pretreatment imaging examinations in patients with UADT-ENKTL. Clinical trial information: NCT01788137.