Optimising the treatment of central nervous system cancers with radiotherapy in adult and paediatric patients

Abstract

CNS tumours in adults and children carry some of the worst prognoses of all cancers. Radiotherapy remains integral to their treatment, particularly for primary high-grade tumours and brain metastasis. The planning and delivery of therapy is technically demanding, requiring precise treatment of tumours that can rapidly progress, delivered to unwell patients and in situations where treatment must be urgently commenced.Maximising tumour control whilst minimising dose to critical organs at risk, remains challenging in the brain. This thesis presents investigations into strategies to optimise the planning and delivery of radiotherapy in both adult and paediatric patients. Four interrelated studies were conducted across all stages of radiotherapy simulation, planning, quality assurance and treatment delivery. The focus of the research was to examine clinically important issues that could be used to improve treatment quality and accuracy.

The first study quantified the impact of the change in brain metastasis during the radiosurgical planning process, demonstrating that clinically significant variations necessitating re-planning occur in a substantial portion of patients. The second study examined the use of knowledge-based planning with RapidPlan for children with diffuse midline glioma, demonstrating that high-quality plans could be produced rapidly, in a clinically urgent situation. The third paper evaluated the introduction of a multi-disciplinary quality assurance checkpoint to improve plan conformity and reduce organ at risk doses. The final study analysed real-world patient setup accuracy and dosimetric impact in cranial-spinal radiotherapy for paediatric, adolescent, and young adult patients.

Collectively, these studies highlight practical and clinically implementable methods to improve the quality of central nervous system radiotherapy.