title: Positron emission tomography scan to determine the need for neck dissection after chemoradiation for head and neck cancer: timing is everything.
abstract: We present a case of a negative positron emission tomography (PET) scan in a patient with pathologic viable cancer at neck dissection.
  
  
  METHODS
  Case Report.
  
  
  METHODS
  A 69-year-old man presented with clinical stage T2N2c squamous cell cancer of the left tonsil and was treated with definitive chemoradiation. Left-sided adenopathy decreased but remained palpable after therapy.
  
  
  RESULTS
  PET scan performed 23 days after completion of treatment showed no suspicious uptake in the left neck. Neck dissection performed at 2 months post-therapy revealed viable tumor in left cervical nodes.
  
  
  CONCLUSIONS
  Persistent adenopathy after chemoradiation for head and neck cancer remains a clinical dilemma. A negative PET scan is accurate but only if the scan is performed 3 to 4 months after therapy.
authors.affiliation: Department of Radiation Oncology, Oregon Health and Science University, Portland, Oregon 97239, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Canning
authors.forename: Samuel
authors.initials: S
authors.lastname: Gubbels
authors.forename: Crispin
authors.initials: C
authors.lastname: Chinn
authors.forename: Mark
authors.initials: M
authors.lastname: Wax
authors.forename: John M
authors.initials: JM
authors.lastname: Holland
mesh_terms: D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000532:radiotherapy / Q000556:secondary / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D002945:Cisplatin / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005472:Fluorouracil / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D009333:Neck / Q000000981:diagnostic imaging*; D037981:Neck Dissection / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014067:Tonsillar Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*
chemical_list: D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D002945:Cisplatin; D005472:Fluorouracil