Defining secure surgical bone margins in head and neck squamous cell carcinomas: The diagnostic impact of intraoperative cytological assessment of bone resection margins compared with preoperative imaging.

Background: Imaging provides crucial staging information for treatment planning of head and neck squamous cell carcinomas (HNSCCs). Despite technical progress in imaging techniques, defining the extent of bone involvement preoperatively remains challenging and requires intraoperative information to control for adequate resection. The intraoperative cytological assessment of the bone resection margins (ICAB) provides information whether bone is infiltrated by carcinoma. The aim of this study was to assess the diagnostic value of preoperative imaging compared with ICAB in order to achieve carcinoma-free bone margins.

Materials And Methods: 108 HNSCC patients underwent preoperative computed tomography (CT), magnetic resonance imaging (MRI) and orthopantomogram (OPG) for staging and surgical planning. Curative resection was planned based on imaging. Intraoperatively, the resection margins were controlled by ICAB. The diagnostic value of preoperative imaging and ICAB was assessed with reference to the histological findings.

Results: CT showed a sensitivity of 89.7%, specificity of 63.0%, positive predictive value (PPV) of 85.9%, and negative predictive value (NPV) of 70.8%. MRI revealed a sensitivity of 45.5%, specificity of 66.7%, PPV of 71.4% and NPV of 40.0%. OPG-imaging had a sensitivity of 64.7%, specificity of 76.2%, PPV of 81.5%, NPV 57.1%. In comparison, ICAB provided a sensitivity of 78.6%, specificity of 95.7%, PPV 73.3%, and NPV 96.7%. The accuracy was 82.1%, 52.9%, 69.0%, and 93.5% for CT, MRI, OPG, and ICAB, respectively.

Conclusion: Preoperative imaging lacks accuracy in defining adequate bone resection margins, compared with ICAB. ICAB supports preoperative imaging and intraoperative frozen sections to improve bone margin control.