title: Midtreatment ¹⁸F-FDG PET/CT Scan for Early Response Assessment of SMILE Therapy in Natural Killer/T-Cell Lymphoma: A Prospective Study from a Single Center.
abstract: In a prospective study of newly diagnosed or relapsed histologically proven extranodal natural killer/T-cell lymphoma (ENKTL) patients, we aimed to determine the accuracy of midtreatment (18)F-FDG PET for response assessment using both visual and quantitative analyses.
  
  
  METHODS
  Twenty-four patients (12 men, 12 women; median age, 50 y; age range, 16-83 y) were referred for pre-, mid- (after 2-3 cycles of SMILE [prednisolone, methotrexate, ifosfamide, L-asparaginase, etoposide] chemotherapy), and end-treatment PET/CT scans (n = 24, 24, and 17, respectively) using a standardized protocol. Sixty-five PET/CT scans were analyzed visually using the Deauville 5-point score (DS), and the lesion with the highest maximum standardized uptake value (SUV(max)) was recorded. Survival curves were obtained using Kaplan-Meier analysis and compared using the log rank test, followed by multivariate analysis using the Cox proportional hazards model to assess the independent effects of International Prognostic Index (IPI) score (0-1 vs. 2-5), stage (stage I/II vs. stage III/IV), sex, DS (1-3 vs. 4-5), SUV(max), and change in SUV(max) on overall survival (OS) and progression-free survival (PFS). The mean (±SD) follow-up period was 32 mo (±21 mo).
  
  
  RESULTS
  For 2-y OS, the following parameters were predictive: IPI score (P = 0.047), DS at mid- and end-treatment (P < 0.001), and SUV(max) at mid- and end-treatment (P < 0.001 and 0.045, respectively). For 2-y PFS, the following parameters were predictive: sex (P = 0.006), stage (P = 0.034), IPI score (P = 0.038), DS at mid- and end-treatment (P < 0.001 and 0.001, respectively), and SUV(max) at midtreatment (P = 0.001). Multivariate analysis showed DS on mid- and end-treatment scans to be the only significant independent predictor of both OS (P = 0.004 and 0.018, respectively) and PFS (P = 0.004 and 0.014, respectively). The 2-y estimate for OS and PFS was 81% and 62%, respectively, in patients with a DS of 1-3, compared with 17% in patients with a DS of 4-5 (P < 0.001 and 0.001, respectively). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the midtreatment DS for prediction of OS and PFS were 63%, 94%, 83%, 83%, and 83%, respectively.
  
  
  CONCLUSIONS
  Midtreatment PET/CT is a valuable tool for early treatment response assessment in extranodal natural killer/T-cell lymphoma patients.
authors.affiliation: Department of Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; and plkhong@hku.hk.
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
authors.affiliation: Department of Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; and.
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; and.
authors.forename: Elaine Yuen Phin
authors.initials: EY
authors.lastname: Lee
authors.affiliation: Department of Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; and.
authors.forename: Winnie Kit Sum
authors.initials: WK
authors.lastname: Chan
authors.affiliation: Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Yok-Lam
authors.initials: YL
authors.lastname: Kwong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols; D001215:Asparaginase / Q000008:administration & dosage / Q000627:therapeutic use; D005047:Etoposide / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007069:Ifosfamide / Q000008:administration & dosage / Q000627:therapeutic use; D016399:Lymphoma, T-Cell / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy*; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage / Q000627:therapeutic use; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011239:Prednisolone / Q000008:administration & dosage / Q000627:therapeutic use; D011446:Prospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D019788:Fluorodeoxyglucose F18; D005047:Etoposide; D011239:Prednisolone; D001215:Asparaginase; D007069:Ifosfamide; D008727:Methotrexate
keywords: 18F-FDG PET/CT; Deauville score (DS); extranodal natural killer/T-cell lymphoma (ENKTL); response assessment