Emerging insights on neoadjuvant chemoradiotherapy in pancreatic cancer

The overall survival of patients with resectable or borderline-resectable pancreatic ductal adenocarcinoma (PDAC) has hardly improved over the last decade with a rise in studies investigating the role of preoperative (neoadjuvant) chemoradiotherapy. Since neoadjuvant chemoradiotherapy has not proven its efficacy yet, little is known about the radiotherapy aspects of pancreatic cancer. As a consequence, no standard guideline is available on delineation of pancreatic tumors in the neoadjuvant setting. It is known that tumor delineation can be challenging, with poor contrast between the tumor and surrounding tissue. This thesis aimed to study the role of neoadjuvant chemoradiotherapy in patients with resectable or borderline-resectable PDAC and investigate the radiotherapeutic aspects: delineation and treatment planning of neoadjuvant radiotherapy. Within this thesis, the suggestion was found that neoadjuvant chemoradiotherapy is beneficial in patients with resectable and borderline-resectable PDAC, especially in the latter group. Further improvements in neoadjuvant chemotherapy using FOLFIRINOX and gemcitabine/nab-Paclitaxel should be investigated, but also should focus on the efficacy of neoadjuvant radiotherapy. Considerable interobserver variation was found in both CT and MRI delineation, and further improvements in radiotherapeutic approaches to reduce the treating volumes are needed, such as MR-guided stereotactic radiotherapy, breathhold or midposition radiotherapy.