Ultrasound-guided oral cancer surgery: An accessible technique for an impactful disease

Abstract

The most effective treatment for oral cancer is surgical removal of the tumor in the mouth. The goal is to remove at least 5 millimeters of healthy tissue around the tumor. If this so-called “tumor-free margin” is not achieved, extra treatment may be needed, such as radiotherapy or another operation. This thesis looks at the feasibility, accuracy, and clinical effect of ultrasound-guided surgery for oral cancers, with a focus on tongue cancer. Ultrasound can be used both during the operation in the mouth (“in-vivo”) and on the removed tissue (“ex-vivo”). Studies in this thesis show that ultrasound-guided tongue surgery more often achieves tumor-free margins, especially in the deeper parts. Because of this, extra treatment was needed less often, without a higher risk of the tumor coming back. Ex-vivo ultrasound can show margins smaller than 5 millimeters, which allows the surgeon to remove extra tissue during the same operation in a targeted way. However, the accuracy of this method still needs improvement. Ultrasound has also been studied in the surgical removal of cheek mucosa cancer, where it is especially difficult to find the right balance between removing enough tissue and preserving cheek function. This thesis also reviews the existing literature on other image-guided surgical techniques, such as fluorescence, MRI, and iodine staining. Finally, a study was done on the use of a powerfull MRI to create digital 3D models of the removed tumor tissue. In the future, these models could help surgeons remove extra tissue more precisely when tumor-free margins are not sufficient.