Head and neck radiotherapy challenges: Cure versus toxicity

The general aim of this thesis was to investigate ways to improve treatment outcome for head and neck cancer patients, ultimately contributing to an increased cure rate and/or decreased toxicity. More specifically, the objectives were: • To assess the success rate of chemoradiotherapy in organ function preservation • To optimize the concurrent treatment strategy and the use of functional imaging in chemoradiotherapy • To optimize adaptive radiotherapy These aims were addressed through a retrospective analysis, clinical studies and an in silico trial. All these aims had a different impact on the trade-off between cure rate and toxicity. PART I of the thesis is an assessment of the standard of care in head and neck cancer. Chapter 2 is a retrospective cohort analysis of organ function preservation failure after (chemo)radiotherapy in head and neck cancer. PART II has 3 chapters in which possible ways to improve treatment outcomes are investigated. Chapter 3 is about the late follow-up of the RADPLAT study, which investigated intra-arterial administration of cisplatin. Chapter 4 describes the ARTFORCE trial about redistribution of radiotherapy dose. Chapter 5 is a treatment planning study that shows redistribution of radiotherapy dose to the primary tumor is expected to be isotoxic to the standard radiotherapy dose distribution. PART III is about adaptive radiotherapy. In Chapter 6 differences between planned and delivered dose for head and neck cancer, and their consequences for normal tissue complication probability and treatment adaptation are investigated. Chapter 7 is a review article about adaptive radiotherapy