title: (18)F-FDG PET in Patients with Primary Systemic Anaplastic Large Cell Lymphoma: Differential Features According to Expression of Anaplastic Lymphoma Kinase.
abstract: OBJECTIVE
  Primary systemic anaplastic large cell lymphoma (ALCL) is divided into two entities according to the expression of anaplastic lymphoma kinase (ALK). We investigated (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) findings in primary systemic ALCL according to ALK expression.
  
  
  METHODS
  Thirty-seven patients who had baseline PET before CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone)-based chemotherapy were enrolled. Among them, patients who underwent interim and/or post-therapy PET were further investigated for the treatment response and survival analysis. Baseline PET was analyzed visually and semi-quantitatively using peakSUV, and interim and post-therapy PETs were visually analyzed.
  
  
  RESULTS
  All cases were (18)F-FDG-avid on baseline PET. The peakSUV of ALK-positive ALCL (n = 16, 18.7 ± 10.5) was higher than that of ALK-negative ALCL (n = 21, 10.0 ± 4.9) (P = 0.006). In ALK-negative ALCL, complete response (CR) rate in negative-interim PET was higher than positive-interim PET (100 % vs 37.5 %, P = 0.02); however, there was no such difference in ALK-positive ALCL (100 % vs 75 %, P = 0.19). The 3-year progression-free survival (PFS) was not significantly different between ALK-positive and ALK-negative ALCL (72.7 % vs 47.6 %, P = 0.34). In ALK-negative ALCL, negative interim and post-therapy PET patients had better 3-year PFS than positive interim (83.3 % vs 25.0 %, P = 0.06) and post-therapy PET patients (70.0 % vs 20.0 %, P = 0.04). In contrast, ALK-positive ALCL had no such differences between PFS and PET results.
  
  
  CONCLUSIONS
  On baseline PET, all cases showed (18)F-FDG-avidity, and ALK expression was related to higher (18)F-FDG uptake. ALK-positive patients tend to have better PFS than ALK-negative patients. Negative-interim PET was a good indicator of CR, and interim or post-therapy PET was helpful for predicting the prognosis only in the ALK-negative group.
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736 Korea.
authors.forename: Dong Yun
authors.initials: DY
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736 Korea.
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736 Korea.
authors.forename: Seol Hoon
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736 Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Chae
authors.affiliation: Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Shin
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Dok Hyun
authors.initials: DH
authors.lastname: Yoon
authors.affiliation: Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Cheolwon
authors.initials: C
authors.lastname: Suh
authors.affiliation: Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jooryung
authors.initials: J
authors.lastname: Huh
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736 Korea.
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Ryu
keywords: 18F-FDG PET; Anaplastic lymphoma kinase; Primary systemic anaplastic large cell lymphoma