title: Whole-body18F-FDG PET/CT for M staging in the patient with newly diagnosed nasopharyngeal carcinoma: Who needs?
abstract: OBJECTIVE
  Although whole-body fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) (18F-FDG PET/CT) is commonly used for M staging of newly diagnosed nasopharyngeal carcinoma (NPC), some patients may not benefit from this procedure. The present study investigated which patients require this modality for M staging.
  
  
  METHODS
  Whole-body18F FDG PET/CT results and clinical data were collected for 264 patients with newly diagnosed NPC. The relationships between distant metastasis and age, gender, pathological type, lesion size, SUVmax-T, T staging, N staging, SUVmax-N and Epstein-Barr virus (EBV) quantity were retrospectively analysed to identify factors associated with increased risk.
  
  
  RESULTS
  Of the 264 patients, only 37 (14.0%) were diagnosed with distant metastasis. Using multiple logistic regression analysis, EBV-positivity (OR=13.1; 95% CI:1.61,106.80), N staging (OR=3.05; 95% CI:1.41,6.63) and T staging (OR=2.16; 95% CI:1.10, 4.24) were significantly related to distant metastasis (all P<0.05). EBV DNA levels≥9000copies/ml, N3 stage and T4 stage were identified as high risk factors. A low risk of distant metastasis was found in patients with 0-1 risk factors and in those with 2 specific risk factors, T3/T4 and N2/N3 staging. Patients with EBV DNA levels ≥9000copies/ml and N3 or T4 staging and those with 3 risk factors had a medium or high risk, with a much higher incidence of distant metastasis (χ2=29.896, P=0.000), and needed a whole-body18F FDG PET/CT for M staging.
  
  
  CONCLUSIONS
  Due to the low incidence of distant metastasis, only patients with medium or high risk need to undergo a whole-body scan.
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yun-Yan
authors.initials: YY
authors.lastname: Ren
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: You-Cai
authors.initials: YC
authors.lastname: Li
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China. Electronic address: wuhbym@163.com.
authors.forename: Hu-Bing
authors.initials: HB
authors.lastname: Wu
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Quan-Shi
authors.initials: QS
authors.lastname: Wang
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yan-Jiang
authors.initials: YJ
authors.lastname: Han
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Wen-Lan
authors.initials: WL
authors.lastname: Zhou
authors.affiliation: Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Hong-Sheng
authors.initials: HS
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging*; D009367:Neoplasm Staging; D018579:Patient Selection; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: (18)F-FDG PET/CT; EBV DNA level; Head and neck cancer; Nasopharyngeal carcinoma; Staging; Whole-body scan