Proceedings of the International Cancer Imaging Society (ICIS) 16th Annual Teaching Course

Abstract

Cancers arise from unregulated cellular growth and exhibits a range of pathophysiological characteristics and behaviour. The term "tumour heterogeneity" encompasses a broad range of tumour features that have arisen as a result of different mechanistic processes including stem-cell origin, tumour evolution (linked to genetic mutations and adverse tumour microenvironment) and clonal resistance (as a consequence of treatment). Tumour heterogeneity may be intra-tumoural (i.e. within the same tumour), intertumoural (i.e. between lesions in the same patient) and interindividual (i.e. between patients). The understanding of tumour heterogeneity is important because it is a barrier to curing cancers; and improved understanding can lead to better individualised treatments. Tumour heterogeneity is linked to treatment resistance and the emergence of aggressive tumour phenotypes. There is thus a need for biomarkers to identify relevant tumour sub-clones to which specific therapies may be directed. Current approaches to enhance our understanding of tumour heterogeneity include genomics analysis using either multi-tumoural region and/or longitudinal tumor tissue sampling. However, non-invasive imaging using CT, MRI and PET imaging can provide an overview of the imaging characteristics of multiple disease sites across the body, thereby provide critical information about intra-and inter-tumour heterogeneity. Using functional and molecular imaging techniques, imaging can be used to quantitatively measure different aspects of tumour biology; thus identifying imaging phenotypes linked to different stem-cell origins, gene expression, tumour evolution, treatment efficacy (including differential treatment response) and the emergence of clonal resistance. The emerging evidence for the use of imaging to explore and understand tumour heterogeneity will be presented and discussed.