Recent advances in radiation oncology

Abstract

Radiotherapy (RT) is very much a technology-driven treatment modality in the management of cancer. RT techniques have changed significantly over the past few decades, thanks to improvements in engineering and computing. We aim to highlight the recent developments in radiation oncology, focusing on the technological and biological advances. We will present state-of-the-art treatment techniques, employing photon beams, such as intensity-modulated RT, volumetric-modulated arc therapy, stereotactic body RT and adaptive RT, which make possible a highly tailored dose distribution with maximum normal tissue sparing. We will analyse all the steps involved in the treatment: imaging, delineation of the tumour and organs at risk, treatment planning and finally image-guidance for accurate tumour localisation before and during treatment delivery. Particular attention will be given to the crucial role that imaging plays throughout the entire process. In the case of adaptive RT, the precise identification of target volumes as well as the monitoring of tumour response/modification during the course of treatment is mainly based on multimodality imaging that integrates morphological, functional and metabolic information. Moreover, real-time imaging of the tumour is essential in breathing adaptive techniques to compensate for tumour motion due to respiration. Brief reference will be made to the recent spread of particle beam therapy, in particular to the use of protons, but also to the yet limited experience of using heavy particles such as carbon ions. Finally, we will analyse the latest biological advances in tumour targeting. Indeed, the effectiveness of RT has been improved not only by technological developments but also through the integration of radiobiological knowledge to produce more efficient and personalised treatment strategies.

Keywords: adaptive radiotherapy; image guided radiotherapy; intensity-modulated radiotherapy; radiogenomics; stereotactic body radiotherapy.

Figure 1.. Axial view of a treatment plan for whole breast irradiation with SIB delivered with TomoTherapy. The colour green corresponds to 95% of the prescribed dose to the breast, and the colour red to 95% of the boost dose.

Figure 2.. Axial view of a volumetric arc therapy (VMAT) treatment plan for prostate cancer delivered with RapidArc, with SIB to DILs.

Figure 3.. Axial view of a stereotactic treatment plan delivered with CyberKnife for an early stage non-small cell lung carcinoma.