Intraoperative cell isolation for a cytological assessment of bone resection margins in patients with head and neck cancer

The intraoperative cytological assessment of bony resection margins (ICAB) is a feasible diagnostic approach to support frozen section for assessment of invasion of margins of soft and hard tissue. However, complex resection margins could challenge both diagnostic approaches. Our objective here was to identify the limitations of intraoperative diagnostic methods for assessing margins. We present an advanced cytological approach to assess complex margins that may solve the problem. Data from 119 patients in whom frozen section was supported by ICAB, were reviewed and the reasons for false results analysed. In 35 patients with squamous cell carcinoma infiltrating bone, specimens (n=100) from the resection margin went through an intraoperative cell isolation process for the cytological assessment of bony margins (ICAB). The results were compared with the histological results of the corresponding margins of bone as a reference. Limitations to the assessment of operative bony margins intraoperatively included an infiltrative histological pattern of growth of the carcinoma, with carcinoma cells disseminated within the cancellous bone, complex and uneven resection margins with soft and bony tissue, inflammation, and signs of previous radiotherapy. Intraoperative cell isolation plus (ICICAB) allowed the microscopic assessment of up to 1 cm³ of bony tissue to detect disseminated carcinoma cells within the cancellous bone with a sensitivity of 92.3% (95% CI 74.9% to 99.1%), and a specificity of 100% (95% CI 95.1% to 100%), and positive and negative predictive values of 100% (95% CI 85.8% to 100%) and 97.4% (95%CI 90.8% to 99.7%), respectively. Intraoperative cell isolation is a feasible new technique to support ICAB and frozen section in the assessment of bony and soft tissue margins.