By Lawrence H. Schwartz, ,Tavis Allison, Binsheng Zhao
This article summarizes progress from the initial imaging biomarkers developed to evaluate tumor shrinkage in response to cancer therapeutics, to the challenges posed by contemporary treatment paradigms which may produce new patterns of response. Current avenues toward meeting this challenge, including volumetrics, radiomics, kinetic modeling, and artificial intelligence, are reviewed. It focuses on computerized tomography (CT) because it is the workhorse of contemporary oncology, generating datasets required to develop novel approaches and creating immediate translational potential. However, the techniques discussed may enhance analysis of any quantitative imaging modality, including FDG-PET and/or MRI. The review of historical progress suggests factors that drive improvement independent of technology: increasing reproducibility, refining conceptual models, quantifying tumor phenotype, and learning from experience.