title: Tumour thickness as a determinant of nodal metastasis in oral tongue carcinoma.
abstract: BACKGROUND
  Tumour thickness is a strong predictor for cervical node involvement in oral cavity squamous cell carcinomas (SCCs), with a recent meta-analysis concluding a 4-mm optimal prognostic cut-off point. No consensus has been reached for the tumour thickness cut-off for oral tongue SCCs.
  
  
  METHODS
  A retrospective review of prospectively collected data from 112 patients by the Northern Sydney Cancer Centre (Australia) with primary oral tongue SCC was conducted. Tumour thickness was measured by standard histopathological techniques and cervical node involvement was determined either from neck dissection histopathology or by clinical and radiological follow-up.
  
  
  RESULTS
  Neck dissection was performed in 78 patients (70%). Tumour thickness was a significant predictor of cervical node disease (P < 0.01), with a median tumour thickness of 5.5 mm. Cervical node metastasis rates for tumours <2, 2-3.9 and ≥4 mm thick were 10%, 42.1% and 46.5%, respectively. The rate of cervical node metastasis was significantly higher for patients with tumours thicker than a cut-off of 2 mm (odds ratio: 7.53, P < 0.01). A 4-mm thickness cut-off was also statistically significant (P < 0.05); however, the odds ratio was smaller at 2.52.
  
  
  CONCLUSIONS
  Despite some previous evidence for a 4-mm tumour thickness cut-off in oral tongue SCCs, thinner tumours (2-3.9 mm) can also have a propensity for cervical node metastasis. Patients in this category require close monitoring for regional recurrence if they do not have a neck dissection.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Royal North Shore Hospital, Sydney, New South Wales, Australia.
authors.forename: Kejia
authors.initials: K
authors.lastname: Wang
authors.affiliation: The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Veivers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000473:pathology*; D009062:Mouth Neoplasms / Q000473:pathology; D009333:Neck / Q000473:pathology; D037981:Neck Dissection / Q000379:methods; D009367:Neoplasm Staging; D012189:Retrospective Studies; D000071036:Sentinel Lymph Node / Q000473:pathology*; D014062:Tongue Neoplasms / Q000473:pathology* / Q000601:surgery
keywords: 
  SCC
  ; neoplasm metastasis; oral cavity