title: Response evaluation of the neck in oropharyngeal cancer: Value of magnetic resonance imaging and influence of p16 in selecting patients for post-radiotherapy neck dissection.
abstract: BACKGROUND
  Residual neck disease after radiotherapy in advanced oropharyngeal squamous cell carcinoma (OPSCC) is associated with increased mortality, and some patients may benefit from post-radiotherapy neck dissection (PRND). The aim of the present study was to assess the value of magnetic resonance imaging (MRI) and other clinical characteristics in selecting patients for PRND.
  
  
  METHODS
  Retrospective cohort study. Consecutive patients with N+ OPSCC were included. Medical records, pathology reports and imaging reports were reviewed. Pre- and post-therapeutic imaging was re-evaluated.
  
  
  RESULTS
  A total of 100 consecutive patients from a three-year period were included. Neck response was evaluated with MRI two months after treatment. Sixty patients were suspicious for residual neck disease, and were offered surgery; seven of these patients had histologic evidence of carcinoma. Cumulative neck failure after three years was 14% (8.4-24%), and did not differ significantly among patients with positive compared to negative MRI (radiologist's initial description; p = 0.47, log-rank test). Applying neck failure as gold standard, sensitivity and specificity of MRI was 69% and 41%, respectively; positive and negative predictive value was 15% and 90%. Patients with p16 + disease had significantly larger lymph nodes after treatment, and imaging based on lymph node size resulted in many false positives. Analysis of receiver operating characteristic curves in 191 individual lymph nodes showed that a short axis ≥ 10 mm should be classified as suspicious. Furthermore, T-stage and p16-status were associated with increased risk of neck recurrence. Salvage was successful in four patients with early detected nodal recurrence.
  
  
  CONCLUSIONS
  These results suggest that lymph node size, T-stage and p16 status could be used in selecting patients for PRND in OPSCC. Yet, early anatomical imaging may be inappropriate for evaluating neck response in patients with p16 + disease as enlarged lymph nodes often do not indicate residual neck disease.
authors.affiliation: a Department of Experimental Clinical Oncology , Aarhus University Hospital , Aarhus , Denmark.|b Department of Otorhinolaryngology-Head & Neck Surgery , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Jacob K
authors.initials: JK
authors.lastname: Lilja-Fischer
authors.affiliation: c Department of Oncology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Jensen
authors.affiliation: d Department of Neuroradiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Helle W
authors.initials: HW
authors.lastname: Eskildsen
authors.affiliation: e Department of Radiology , Aalborg University Hospital , Aarhus , Denmark.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Fink-Jensen
authors.affiliation: b Department of Otorhinolaryngology-Head & Neck Surgery , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Viveque E
authors.initials: VE
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000556:secondary / Q000628:therapy*; D003131:Combined Modality Therapy; D019941:Cyclin-Dependent Kinase Inhibitor p16; D018572:Disease-Free Survival; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009363:Neoplasm Proteins / Q000032:analysis*; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000601:surgery; D018365:Neoplasm, Residual; D009929:Organ Size; D009959:Oropharyngeal Neoplasms / Q000737:chemistry / Q000473:pathology / Q000628:therapy*; D018579:Patient Selection; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009363:Neoplasm Proteins