In oral squamous cell carcinoma (OSCC), depth of invasion (DOI) is an important predictive, prognostic, and staging parameter. While it is known that DOI can be estimated from preoperative imaging, an analysis of measurements variations according to imaging modality and to depth of tumor itself is lacking. The aim of the study was to assess the accuracy of imaging-based estimation of DOI in relation with the tumor histological DOI. We retrospectively reviewed 121 patients with OSCC treated at University Hospital Zurich. The radiologic DOI of CT, T1-weighted, and T2-weighted MRI were compared with histological DOI. Frequency of relevant imaging artifacts was assessed as well. A total of 110 CT (90.9 %) and 90 MRI (74 %) were analyzed. Both modalities were available for 79 patients (65.3 %). The median histological depth of invasion was 9 mm (IQR 4.5-14). The median depth of invasion was 14 mm (IQR 10-20) on CT, 13 mm (IQR 8.25-18) on T1-weighted MRI, and 13 mm (IQR 9-18.75) on T2-weighted MRI. All diagnostic modalities tended towards an overestimation of the histopathologic DOI from about 5-15 %. This trend was most pronounced for thin tumors, for which both CT and MRI lead to upstaging in over 50 % of the cases. For 25 (22.7 %) patients, dental scattering on CT rendered DOI not estimable. For MRI, 18 patients (20 %) had artifacts (blooming, motion artifacts) rendering DOI not estimable. CT and MRI measurements of DOI in OSCC lead to an overestimation of histological DOI, especially in tumors with DOI<5 mm, with upstaging by imaging in over 50 % of the cases. Artifacts were present in more than 20 % of performed images.

Background: In the past few decades, a re-evaluation of treatment paradigms of head and neck cancers with a desire to spare patients the treatment-related toxicities of open surgery, has led to the development of new minimally invasive surgical techniques to improve outcomes. Besides Transoral Laser Microsurgery (TLM), a newroboticsurgical technique namely Transoral Robotic Surgery (TORS) emerged for the first time as one of the two most prominent and widely used minimally invasive surgical approaches particularly for the treatment of oropharyngeal cancer, a sub-entity of head and neck cancers. Recent population-level data suggest equivalent tumor control, but different total costs, and need for adjuvant chemoradiation. A comparative analysis of these two techniques is therefore warranted from the cost-utility (C/U) point of view.Methods: A cost-utility analysis for comparing TORS and TLM was performed using a decision-analytical model. The analyses adopted the perspective of a Swiss hospital. Two tertiary referral centers in Lausanne and Zurich provided data for model quantificantion.Results: In the base case analysis TLM dominates TORS. This advantage remains robust, even if the costs for TORS reduce by up to 25%. TORS begins to dominate TLM, if less than 59,7% patients require adjuvant treatment, whereby in an interval between 55 and 62% cost effectiveness of TORS is sensitive to the prescription of adjuvant chemoradiation therapy (CRT). Exceeding 29% of TLM patients requiring a revision of surgical margins renders TORS more cost-effective.Conclusion: Non-robotic endoscopic surgery (TLM) is more cost-effective than robotic endoscopic surgery (TORS) for the treatment of oropharyngeal cancers. However, this advantage is sensitive to various parameters, i.e.to the number of re-operations and adjuvant treatment.