Use of Transoral Ultrasound for Measuring Depth Of Invasion in Oral Tongue Carcinoma, and Comparing Obtained Measurements With Measurements From MRI With the Results Obtained From Pathological Examination of Surgically Resected Specimens

The investigators will conduct a prospective cohort study to investigate the correlation between DOI measurements from preoperative imaging (MRI and intraoral ultrasound), and final histopathology findings.

All patients with oral tongue cancer histologically verified on biopsy diagnosed in the Capital Region and Zealand Region (population 2.6 mio) are treated at the department of Head and Neck surgery at Copenhagen University Hospital (Rigshospitalet). These patients will be invited to participate in the study before or at their multidisciplinary team (MDT) conference at Rigshospitalet where the final treatment will be decided.

The ultrasound exam is conducted with a bk5000 or bk3000 machine, a "Hockey Stick" X18L5s transducer or a 18L5s Linear transducer.

The transducer will be placed directly on the tongue tumor. The tumor size will be measured, and depth of invasion will be estimated. For later reevaluation of the ultrasound images, a sweep will be performed, and image files and video clips will be stored for documentation.

Patients will primarily be examined in the outpatient clinic, and the measurement will be repeated at the time of surgery when the patient is in general anesthesia. It is, however, at time of the examination outpatient clinic that the information about DOI is most useful in planning the treatment, and therefore this is measurement the investigators will be focusing on.