title: Impact of a second FDG PET scan before adjuvant therapy for the early detection of residual/relapsing tumours in high-risk patients with oral cavity cancer and pathological extracapsular spread.
abstract: OBJECTIVE
  Extracapsular spread (ECS) to the cervical lymph nodes is a major adverse prognostic factor in oral cavity squamous cell carcinoma (OSCC). We prospectively examined the value of FDG PET immediately before postoperative radiotherapy/concurrent chemoradiotherapy (pre-RT/CCRT PET) to detect residual/relapsing disease in the early postsurgical follow-up period in high-risk OSCC patients with ECS.
  
  
  METHODS
  We examined 183 high-risk OSCC patients with ECS who underwent preoperative FDG PET/CT for staging purposes. Of these patients, 29 underwent a second pre-RT/CCRT FDG PET/CT scan. The clinical utility of the second FDG PET/CT was examined using Kaplan-Meier curve analysis.
  
  
  RESULTS
  Patients who underwent the second FDG PET/CT scan had baseline clinicopathological characteristics similar to those who did not undergo a second scan. Of the patients who underwent the second scan, seven (24 %) had unexpected, newly discovered lesions. Five eventually died of the disease, and two had no evidence of recurrence after a change in RT field and dose. In an event-based analysis at 2 months, rates of neck control (6/29 vs. 6/154, p = 0.001), distant metastases (3/29 vs. 4/154, p = 0.046), and disease-free survival (7/29 vs. 10/154, p = 0.003) were significantly higher in patients who received a second PET scan than in those who did not. The second pre-RT/CCRT PET scan was of particular benefit for detecting new lesions in OSCC patients with both ECS and lymph node standardized uptake value (SUV) of ≥ 5.2 in the first PET scan.
  
  
  CONCLUSIONS
  The present findings support the clinical value of pre-RT/CCRT FDG PET for defining treatment strategy in OSCC patients with both ECS and high nodal SUV, even when FDG PET had already been performed during the initial staging work-up.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, Republic of China.
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Kang-Hsing
authors.initials: KH
authors.lastname: Fan
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Shiang-Fu
authors.initials: SF
authors.lastname: Huang
authors.forename: I-How
authors.initials: IH
authors.lastname: Chen
authors.forename: Chung-Jan
authors.initials: CJ
authors.lastname: Kang
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Chuen
authors.initials: C
authors.lastname: Hsueh
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Lee
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
mesh_terms: D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D018365:Neoplasm, Residual; D049268:Positron-Emission Tomography / Q000379:methods*; D018714:Radiotherapy, Adjuvant; D012008:Recurrence; D012306:Risk; D016019:Survival Analysis
chemical_list: D019788:Fluorodeoxyglucose F18