PhD defence R.W.H. (Roeland) Smits

The primary choice of treatment for oral cavity cancer is surgery. The most important goal of surgery is to excise the tumor with adequate resection margins (>5 mm distance between tumor border and resection surface), because patient outcome is negatively affected when adequate resection margins are not achieved. We show that adequate margins are only achieved in 15% of cases at Erasmus MC and Leiden UMC. We also showed a significant difference in recurrence of disease, metastasis and survival in favor of the patients with adequate resection margins. We hypothesize that the main reason for the high number of inadequate margins is the lack of a method to evaluate the entire resection surface intraoperatively. The same is true for bone resection margins, there is lack of a reliable method to evaluate the bone resection margin. We found 21% tumor-positive bone resection margins.  We evaluate different methods for intraoperative assessment of resection margins. Specimen-driven intraoperative assessment showed best results with 58% adequate margins. Other potential methods and techniques were also evaluated. Raman spectroscopy is able to differentiate between tumor and surrounding healthy tissue. We show that there is a clear difference in water concentration between tumor and healthy tissue. Furthermore, Raman spectroscopy is able to differentiate between tumor and healthy tissue fast and reliable. Raman Spectroscopy was then used to differentiate between water concentration of the tumor and surrounding healthy tissue in order to set the adequate resection margin.

The public defence will take place at the Senate Hall, 1st floor Erasmus Building, location campus Woudestein. The ceremony will begin exactly at 10.30 AM. In light of the solemn nature of the ceremony, we recommend that you do not take children under the age of 6 to the first part of the ceremony.