title: Exploration for an Algorithm for Deintensification to Exclude the Retropharyngeal Site From Advanced Oropharyngeal Squamous Cell Carcinoma Treatment.
abstract: OBJECTIVE
  Understanding the drainage patterns to the retropharyngeal lymph nodes is an important consideration in oropharyngeal squamous cell carcinoma (OPSCC) because treatment of these nodes is related to increased morbidity. Prediction of these drainage patterns could not only help minimize treatment morbidity but also prevent failures in at-risk patients as deintensification trials are under way for this disease.
  
  
  OBJECTIVE
  To evaluate the prevalence of pathologic retropharyngeal adenopathy (RPA) in OPSCC relative to involvement of the oropharyngeal subsite, number of metastatic neck nodes, T classification, and N classification.
  
  
  METHODS
  We performed a retrospective review from January 1, 2003, through December 31, 2010, at an academic referral center of 205 previously untreated patients with pathologically confirmed, advanced-stage (III, IV) OPSCC. Data analysis was performed from January 1, 2013, through June 30, 2015.
  
  
  METHODS
  Concurrent chemoradiotherapy.
  
  
  METHODS
  Radiologic evidence of pathologic RPA was tabulated and related to involvement of the oropharyngeal subsite, number of metastatic neck nodes, T classification, and N classification.
  
  
  RESULTS
  Of the 205 previously untreated patients (183 men; mean age, 56.1 years), pathologic RPA was identified in 37 (18.0%) of the 205 patients. Pathologic retropharyngeal lymph nodes were found in 12 (13.5%) of 89 patients with base of tongue cancers, 24 (22.0%) of 109 patients with tonsil cancers, and 1 (14.3%) of 7 patients with other oropharyngeal subsite cancers. Increasing prevalence of RPA was positively correlated with closer proximity to the posterior tonsillar pillar. A multivariable logistic regression model using the oropharyngeal subsite, involvement of the posterior tonsillar pillar, number of metastatic neck nodes, T classification, and N classification revealed that the number of metastatic neck nodes was statistically significant (odds ratio, 1.44; 95% CI, 1.20-1.71; P < .001).
  
  
  CONCLUSIONS
  The prevalence of pathologic RPA in this cohort was 18.0%, and patients with multiple nodes had the highest risk of pathologic RPA, followed by involvement of the posterior tonsillar pillar. However, these data suggest that there is no clear algorithm that can be used for deintensification to exclude the retropharyngeal site from the treatment volume using extent of disease gathered from pretreatment imaging for patients with advanced-stage OPSCC.
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Spector
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Steven B
authors.initials: SB
authors.lastname: Chinn
authors.affiliation: Department of Biostatistics, University of Michigan, Ann Arbor.
authors.forename: Emily
authors.initials: E
authors.lastname: Bellile
authors.affiliation: Department of Otolaryngology, Baylor College of Medicine, Houston, Texas.
authors.forename: K Kelly
authors.initials: KK
authors.lastname: Gallagher
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Kang
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Moyer
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Prince
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Wolf
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Carol R
authors.initials: CR
authors.lastname: Bradford
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: McHugh
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Carey
authors.affiliation: Department of Medical Oncology, University of Michigan, Ann Arbor.
authors.forename: Francis P
authors.initials: FP
authors.lastname: Worden
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor.
authors.forename: Avraham
authors.initials: A
authors.lastname: Eisbruch
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor.
authors.forename: Mohannad
authors.initials: M
authors.lastname: Ibrahim
authors.affiliation: Department of Otolaryngology, University of Michigan, Ann Arbor8Department of Otolaryngology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Chepeha
mesh_terms: D000465:Algorithms; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000556:secondary / Q000628:therapy; D059248:Chemoradiotherapy; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck; D009367:Neoplasm Staging / Q000145:classification*; D009959:Oropharyngeal Neoplasms / Q000473:pathology* / Q000628:therapy; D049268:Positron-Emission Tomography; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents