Optical coherence tomography for surgical margin assessment of soft-tissue sarcomas of the extremities and trunk

Introduction Incomplete resection of superficial trunk and extremity soft-tissue sarcomas can impact the risk of local recurrence and overall prognosis for patients after surgical resection. Multiple methods have been described for intraoperative surgical margin assessment of soft-tissue sarcomas, including optical coherence tomography (OCT) evaluation of surgical margins. The accuracy of OCT imaging for evaluating the surgical margins of soft-tissue sarcoma has not been reported. The first aim of this study was to determine the OCT imaging features of different tissue types at the surgical margins when compared to histopathology to allow for image interpretation training for observers. The second aim was to determine the diagnostic accuracy of OCT for identification of incomplete margin status for soft-tissue sarcomas of the superficial trunk or extremities. Methods The surgical margins of 20 soft-tissue sarcoma specimens were imaged using OCT following surgical resection. The OCT images from the first five tumors were used to identify features of different tissue types compared to histopathology and create a training presentation. The OCT images from all tumors were then used to create a training set and test set. Seven observers underwent a training session using a training presentation and interpreted a training and test set. Images were graded on a numeric scale from 1 (no tumor present) to 4 (tumor present). The results of the test set were used to evaluate the sensitivity, specificity, accuracy, and inter- and intraobserver variability. Results The overall sensitivity and specificity for detection of tumor on the surgical margin were 83.5% [95% confidence interval (CI): 74.6% -89.7%] and 76.8% (95% CI: 68.2% -83.6%), respectively. The overall correct classification rate of the surgical margin was 162/203 (79.8%; 95% CI: 73.8% -84.7%). Discussion Further research is needed in an intraoperative setting with a larger patient population to evaluate the use of OCT to evaluate the surgical margins for soft-tissue sarcomas.