title: Impact of perineural invasion in the pathologically N0 neck in oral cavity squamous cell carcinoma.
abstract: OBJECTIVE
  Patients with oral cavity squamous cell carcinoma (OCSCC) undergo adjuvant radiation for pathologically high-risk features including positive nodal disease and extracapsular spread (ECS). In the absence of these high-risk features, our objective was to determine if perineural invasion (PNI) is an independent risk factor and if adjuvant radiation (XRT) improves disease control rates.
  
  
  METHODS
  Historical cohort analysis.
  
  
  METHODS
  Tertiary university hospital.
  
  
  METHODS
  Eighty-eight OCSCC patients (46 males, 42 females; mean age = 56.7 years; median follow-up = 4.6 years) treated surgically with pathologically N0 (pN0) necks were studied. Overall, 23% (20/88) were pN0/PNI+ and of those with PNI, 70% (14/20) underwent XRT. Survival analysis using Kaplan-Meier followed by multivariable Cox models was performed.
  
  
  RESULTS
  Multivariate analysis verified PNI to be associated with worse disease-free interval (DFI) (P = .012) and local-regional control (LRC) (P = .005) and perivascular invasion (PVI) associated with worse DFI (P = .05). Among pN0/PNI+ patients, those who received XRT demonstrated significantly improved DFI (mean = 6.5 years vs 1.7 years; P = .014) and LRC (mean 6.7 years vs 1.9 years; P = .047). There was no improvement in overall survival (P = .68) or disease-specific survival (P = .8) in those receiving XRT.
  
  
  CONCLUSIONS
  PNI is an independent adverse risk factor in the absence of nodal metastasis and extracapsular spread. We observed a statistically significantly longer DFI and LRC when patients were treated with adjuvant radiation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
authors.forename: Steven B
authors.initials: SB
authors.lastname: Chinn
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Spector
authors.forename: Emily L
authors.initials: EL
authors.lastname: Bellile
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: McHugh
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Gernon
authors.forename: Carol R
authors.initials: CR
authors.lastname: Bradford
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Wolf
authors.forename: Avraham
authors.initials: A
authors.lastname: Eisbruch
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Chepeha
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D037981:Neck Dissection; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010525:Peripheral Nerves / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome
keywords: oral cavity; perineural invasion; squamous cell carcinoma