title: Retropharyngeal nodes in squamous cell carcinoma of oropharynx: incidence, localization, and implications for target volume.
abstract: OBJECTIVE
  To investigate the incidence and anatomic localization of retropharyngeal (RP) nodal involvement in patients with squamous cell carcinoma of the oropharynx.
  
  
  METHODS
  The CT studies of 208 patients presenting with oropharyngeal carcinoma were retrospectively analyzed. The location of the nodal neck disease was registered according to recent consensus guidelines for target volume delineation, and special attention was given to the RP nodes. To obtain statistically significant predictors for RP nodal involvement, univariate and multivariate analyses were performed.
  
  
  RESULTS
  RP adenopathies were present in 16% of all patients and in 23% of those patients with nodal disease in other neck sites. Ipsilateral involvement of Level II and contralateral involvement of Level III predicted for involvement of the ipsilateral RP nodes on multivariate analysis (p < 0.05). A solitary ipsilateral RP node was present in 3 (9%) of 34 patients with RP nodes; 2 of these 3 patients had a primary posterior pharyngeal wall tumor. No patients presented with a solitary contralateral RP node.
  
  
  CONCLUSIONS
  Given the high incidence of RP nodal involvement in oropharyngeal cancer-16% of all patients and 23% of patients with pathologic nodal disease in other neck sites-RP nodes should be included in the target volume, especially in node-positive necks. In node-negative necks, inclusion of RP nodes into the target volume is advised in posterior pharyngeal wall tumors.
authors.affiliation: Department of Radiation Oncology, Leuvens Kanker Instituut (LKI), University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bussels
authors.forename: Robert
authors.initials: R
authors.lastname: Hermans
authors.forename: Alex
authors.initials: A
authors.lastname: Reijnders
authors.forename: Piet
authors.initials: P
authors.lastname: Dirix
authors.forename: Sandra
authors.initials: S
authors.lastname: Nuyts
authors.forename: Walter
authors.initials: W
authors.lastname: Van den Bogaert
mesh_terms: D000704:Analysis of Variance; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000556:secondary; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D009367:Neoplasm Staging; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging*; D010614:Pharynx; D011859:Radiography; D012189:Retrospective Studies