title: Predictive and prognostic value of PET/CT imaging post-chemoradiotherapy and clinical decision-making consequences in locally advanced head & neck squamous cell carcinoma: a retrospective study.
abstract: BACKGROUND
  The accuracy of (18)F-fluorodeoxygluocose positron emission tomography/computed tomography (PET/CT) in predicting immediate failure after radical chemoradiotherapy (CRT) for HNSCC is poorly characterized at present. The purpose of this study was to examine PET/CT as a predictive and prognostic gauge of immediate failure after CRT and determine the impact of these studies on clinical decision making in terms of salvage surgery.
  
  
  METHODS
  Medical records of 78 consecutive patients receiving radical CRT for locally advanced HNSCC were reviewed, analyzing PET/CTs done before and 3 months after CRT. Immediate failure was defined as residual disease or locoregional and/or systemic relapse within 6 months after CRT.
  
  
  RESULTS
  Maximum standard uptake value (SUV) of post CRT PET/CT (postSUVmax) was found optimal for predicting immediate failure at a cutpoint of 4.4. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 90.0%, 83.8%, 98.3%, and 45.0%, respectively. Of 78 patients studied, postSUVmax ≥ 4.4 prevailed in 20 (25.6%), with postSUVmax <4.4 in 58 (74.4%). At postSUVmax ≥ 4.4 (vs. postSUVmax <4.4) OS was poorer by comparison (3-year OS: 56.9 vs. 87.7%; P = 0.005), as was progression-free survival (3-year PFS: 42.9 vs. 81.1%; P < 0.001). At postSUVmax ≥ 4.4, OS with and without immediate salvage surgery did not differ significantly (3-year OS: 60.0 vs. 55.6%; Log-rank P = 0.913).
  
  
  CONCLUSIONS
  Post CRT PET/CT imaging has prognostic value in terms of OS and PFS and is useful in predicting immediate therapeutic failure, given its high NPV. However, OS was not significantly altered by early salvage surgery done on the basis of post CRT PET/CT findings.
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. chrono0707@icloud.com.
authors.forename: Ryul
authors.initials: R
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. ock.chanyoung@gmail.com.
authors.forename: Chan-Young
authors.initials: CY
authors.lastname: Ock
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. bhumsuk@snu.ac.kr.|Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. bhumsuk@snu.ac.kr.
authors.forename: Bhumsuk
authors.initials: B
authors.lastname: Keam
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. gabriel9@snu.ac.kr.|Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. gabriel9@snu.ac.kr.
authors.forename: Tae Min
authors.initials: TM
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea. jinho.kim.md@gmail.com.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea. paengjc@snu.ac.kr.
authors.forename: Jin Chul
authors.initials: JC
authors.lastname: Paeng
authors.affiliation: Department of Otorhinolaryngology, Seoul National University Hospital, Seoul, Korea. otolarynx@hanmail.net.
authors.forename: Seong Keun
authors.initials: SK
authors.lastname: Kwon
authors.affiliation: Department of Otorhinolaryngology, Seoul National University Hospital, Seoul, Korea. jhunhah@gmail.com.
authors.forename: J Hun
authors.initials: JH
authors.lastname: Hah
authors.affiliation: Department of Otorhinolaryngology, Seoul National University Hospital, Seoul, Korea. kwontk@snu.ac.kr.
authors.forename: Tack-Kyun
authors.initials: TK
authors.lastname: Kwon
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. kimdw@snu.ac.kr.|Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. kimdw@snu.ac.kr.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea. wuhg@snuh.org.
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
authors.affiliation: Department of Otorhinolaryngology, Seoul National University Hospital, Seoul, Korea. mwsung@snu.ac.kr.
authors.forename: Myung-Whun
authors.initials: MW
authors.lastname: Sung
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 110-744, Seoul, Korea. heo1013@snu.ac.kr.|Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea. heo1013@snu.ac.kr.
authors.forename: Dae Seog
authors.initials: DS
authors.lastname: Heo
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D012372:ROC Curve; D012189:Retrospective Studies; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult