Oncologic imaging end-points for the assessment of therapy response

Sophisticated clinical and diagnostic imaging modalities are critical for the detection, staging, treatment, and follow-up surveillance of cancer. Previously, uni- and bi-dimensional measurements of a tumor lesion were considered the "holy grail" of the assessment of tumor growth and provided imaging end-points for cytotoxic chemotherapeutic agents. With increasing understanding of cancer-related pathways and emerging discoveries of targeted signal transduction inhibitors for cancer treatment, novel pharmacodynamic endpoints of treatment efficacy are required. The innovations in medical imaging include computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), positron emission tomography (PET), single photon emission tomography (SPECT), ultrasonography (US) and, mostly in the pre-clinical arena, optical imaging. While CT and MRI provide superb anatomic resolution, physiological changes in tumor microenvironment can be assessed by dynamic contrast enhanced MRI (DCE-MRI), metabolic endpoints can be established with PET and MRS protocol, and molecular biomarkers can be non-invasively followed up using PET and MRI-based molecular probes (and optical imaging mostly in pre-clinical setting). Novel protocols for improved spatial resolution, automated quantitative methods for anatomic assessment, and development of physiological, metabolic and molecular imaging probes are currently under investigation. The imaging future promises new avenues for exploration of physiological, metabolic, molecular and genetic events in the human body, performed non-invasively and in real time, using multi-modality imaging platforms. The aim of this article is to represent the available patents on imaging response assessment in oncology.