Principles of cancer treatment by radiotherapy

Radiotherapy is a component of cancer management in more than 50% of cases, and 40% of patients cured of their cancer have had radiotherapy as a part of their management. It can be used to control symptoms in patients with incurable cancer. For some patients, it can replace surgery and has the advantage of organ preservation. It is sometimes used before or after surgery to improve resection rates or to reduce recurrence rates, respectively. Outcomes may be improved if radiotherapy is combined with systemic therapies such as chemotherapy. The process of delivering radiotherapy has multiple steps and involves clinical oncologists, medical physicists and therapeutic radiographers. Each step takes advantage of new technology that allows a more accurate definition of the tumour and delivery of the radiation with the aim of improving treatment outcomes and reducing normal tissue toxicity. There have been significant advances in defining the target and delivering the radiation in the last few years and these are discussed further in this article.