title: Tumour thickness in oral cancer using an intra-oral ultrasound probe.
abstract: OBJECTIVE
  To investigate tumour-thickness measurement with an intra-operative ultrasound (US) probe.
  
  
  METHODS
  A retrospective data analysis was undertaken for a total of 65 patients with a T1-2 oral cavity cancer, who were seen at a tertiary referral centre between 2004 and 2010. The correspondence between tumour thickness measured by ultrasonography and histopathology was assessed by Pearson's correlation coefficient, and also between tumour thickness and the development of neck metastasis.
  
  
  RESULTS
  In 11 cases, intra-oral measurement was not optimal due to limited mouth opening (n=2) or impossibility to depict the lesion (n=9). Tumour thickness measured by US correlated well with histopathology (n=23, R=0.93). Tumour thickness of ≤7 mm carries a risk of lymph node metastasis of 12%, whereas in tumours exceeding 7 mm this risk is 57% (p=0.001). Twenty-five percent developed neck metastasis and 19% had local recurrence.
  
  
  CONCLUSIONS
  Tumour thickness is an important predictive marker for lymph node metastases. As such, it can help in decision-making with regard to management of the primary tumour and neck. Based upon our findings, a wait-and-see policy is only warranted for superficial lesions with tumour thickness of less than 7 mm, but only if regular follow-up using US-guided aspiration of the neck is ensured.
authors.affiliation: Department of Head & Neck Surgery and Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, and Department of Otorhinolaryngology, Academic Medical Centre, University of Amsterdam, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
authors.forename: Wouter L
authors.initials: WL
authors.lastname: Lodder
authors.forename: Hendrik J
authors.initials: HJ
authors.lastname: Teertstra
authors.forename: Ing B
authors.initials: IB
authors.lastname: Tan
authors.forename: Frank A
authors.initials: FA
authors.lastname: Pameijer
authors.forename: Ludi E
authors.initials: LE
authors.lastname: Smeele
authors.forename: Marie-Louise F
authors.initials: ML
authors.lastname: van Velthuysen
authors.forename: Michiel W M
authors.initials: MW
authors.lastname: van den Brekel
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D009062:Mouth Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D012189:Retrospective Studies; D047368:Tumor Burden; D014465:Ultrasonics; D014463:Ultrasonography