title: Synchronous malignancies in patients with squamous cell carcinomas of the oral cavity.
abstract: OBJECTIVE
  Synchronous malignancies in patients with squamous cell carcinomas of the oral cavity (OCSCC) are occasionally encountered. In the current study we tried to evaluate their frequency, detectability by (18)F-fluorodeoxyglucose (FDG) studies, and prognostic factors.
  
  
  METHODS
  A retrospective analysis of patients with primary OCSCC enrolled for (18)F-FDG studies from 2002 to 2008 was performed. The detectability of synchronous second cancers by (18)F-FDG studies was defined by the scoring of two interpreters. Prognostic factors for overall survival in patients receiving curative-intent treatment were assessed using the univariate Kaplan-Mayer analysis and the multivariate Cox regression model.
  
  
  RESULTS
  Of 764 patients, 40 (5.2%) had synchronous malignancies. (18)F-FDG studies detected 22 (48%) of 46 synchronous second cancers. For synchronous cancers at the hypopharynx, esophagus, or liver, the median survival of patients was no longer than 1 year, and the detection rates by (18)F-FDG studies were 100, 86, and 25%, respectively. In the 33 patients receiving curative-intent treatment, the site of second cancer, complete surgical resection of all known tumors, and the oral habit of betel quid/areca nut chewing are significant prognostic factors in the univariate analysis, while the site of second cancer is the only significant prognostic factor in the multivariate analysis (p = 0.041).
  
  
  CONCLUSIONS
  The site of second cancer is the most significant prognostic factor in OCSCC patients with synchronous malignancies receiving curative-intent treatment. (18)F-FDG studies detect synchronous malignancies with poor prognosis in OCSCC patients except for hepatic cancers. In OCSCC patients with synchronous malignancies with poor prognosis, prospective studies comparing different treatment options should be further conducted.
authors.affiliation: Department of Nuclear Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Chiayi, Taiwan.
authors.forename: Feng-Yuan
authors.initials: FY
authors.lastname: Liu
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy; D049268:Positron-Emission Tomography; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18