title: Optical coherence tomography in the assessment of oral squamous cell carcinoma resection margins.
abstract: BACKGROUND
  Incomplete surgical removal of cancer is believed to be the main cause of local recurrence and high mortality. This study assessed the use of optical technology (namely optical coherence tomography [OCT]) in examining oral squamous cell carcinoma (OSCC) resection margins to assess if this modality could guide the surgeon during surgical resections.
  
  
  METHODS
  Twenty-eight T1-T2 N0M0 oral squamous cell carcinoma patients participated in this study. Nineteen patients were males and nine were females. The majority of lesions were in the ventro-lateral tongue, floor of mouth, retromolar trigone and the buccal mucosa. Following tumour resection, the specimen resection margins were optically scanned in the immediate ex vivo phase. Two independent assessors commented on the four resection margins of each specimen. The findings were then compared to the corresponding gold standard histopathology. The average epithelial thickness for both tumor-free and tumor-involved margins was also calculated.
  
  
  RESULTS
  The pathology reports of the 112 margins revealed 90 tumor-free margins and 22 tumor-involved margins. Examining the data from both senior operating surgeons (assessors), the overall sensitivity and specificity was found to be 81.5% and 87%, respectively. Whilst the positive predictive value was 61.5% and the negative predictive value was 95%. OCT accuracy for the first assessor was 88% and for the second assessor 84%. The assessors' inter-observer agreement was "very good" for superior, inferior and medial margins; while agreement on the lateral surgical margin status was "good". Using OCT, the mean epithelial thickness at the tumor-free resection margins was 360 μm; while, it was 567 μm for the tumour-involved margins.
  
  
  CONCLUSIONS
  OCT is a valuable tool in the assessment of surgical margins. Tumour-involved margins can be identified by architectural changes and increase in epithelial layer thickness on the OCT image. Further studies are required to assess tumour margins in vivo.
authors.affiliation: Unit of Oral and Maxillofacial Surgery, UCL Eastman Dental Institute, London, UK; Head and Neck Centre, University College London Hospitals, London, UK. Electronic address: zaid19772000@yahoo.com.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Hamdoon
authors.affiliation: UCL Department of Surgery, London, UK. Electronic address: waseem_wk1@yahoo.co.uk.
authors.forename: Waseem
authors.initials: W
authors.lastname: Jerjes
authors.affiliation: UCL Department of Surgery, London, UK. Electronic address: gordon.mckenzie@md-ltd.co.uk.
authors.forename: Gordon
authors.initials: G
authors.lastname: McKenzie
authors.affiliation: Head and Neck Centre, University College London Hospitals, London, UK. Electronic address: amritajk@msn.com.
authors.forename: Amrita
authors.initials: A
authors.lastname: Jay
authors.affiliation: Unit of Oral and Maxillofacial Surgery, UCL Eastman Dental Institute, London, UK; Head and Neck Centre, University College London Hospitals, London, UK; UCL Department of Surgery, London, UK. Electronic address: c.hopper@ucl.ac.uk.
authors.forename: Colin
authors.initials: C
authors.lastname: Hopper
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D000072662:Margins of Excision; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D018365:Neoplasm, Residual; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: Optical coherence tomography; Oral squamous cell carcinoma; Resection margins