Imaging biomarkers for evaluating tumor response: RECIST and beyond

Abstract

Response Evaluation Criteria in Solid Tumors (RECIST) is the gold standard for assessment of treatment response in solid tumors. Morphologic change of tumor size evaluated by RECIST is often correlated with survival length and has been considered as a surrogate endpoint of therapeutic efficacy. However, the detection of morphologic change alone may not be sufficient for assessing response to new anti-cancer medication in all solid tumors. During the past fifteen years, several molecular-targeted therapies and immunotherapies have emerged in cancer treatment which work by disrupting signaling pathways and inhibited cell growth. Tumor necrosis or lack of tumor progression is associated with a good therapeutic response even in the absence of tumor shrinkage. Therefore, the use of unmodified RECIST criteria to estimate morphological changes of tumor alone may not be sufficient to estimate tumor response for these new anti-cancer drugs. Several studies have reported the low reliability of RECIST in evaluating treatment response in different tumors such as hepatocellular carcinoma, lung cancer, prostate cancer, brain glioma, bone metastasis, and lymphoma. There is an increased need for new medical imaging biomarkers, considering the changes in tumor viability, metabolic activity, and attenuation, which are related to early tumor response. Promising imaging techniques, beyond RECIST, include dynamic contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI), diffusion-weight imaging (DWI), magnetic resonance spectroscopy (MRS), and 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET). This review outlines the current RECIST with their limitations and the new emerging concepts of imaging biomarkers in oncology.

Movement Disorders in Oncology: From Clinical Features to Biomarkers

“…Within the context of brain malignancies, the gold standard is the complete or partial tumor removal, based on its location, and/or the prompt initiation of chemo/radiotherapy [ 54 , 55 ]. Again, in the case of paraneoplastic conditions, the first therapeutic step is the oncological treatment of the underlying tumor (if diagnosed), and, when necessary, the administration of first-line drugs able to suppress the immune response, such as intravenous (IV) steroids, IV high-dose immunoglobulins, and plasma-exchange [ 24 ].…”

Emerging Role for 7T MRI and Metabolic Imaging for Pancreatic and Liver Cancer

“…The difficulty of monitoring treatment response with structural images is a major hindrance to precision medicine methods for treating pancreatic ductal adenocarcinoma [ 59 ]. The MRI-derived apparent diffusion coefficient—one of the most promising imaging modalities for quantifying treatment response—outperforms typical imaging criteria for tumor response (e.g., RECIST and mRECIST) though is still insufficient for distinguishing between responders and non-responders to chemotherapy [ 60 ]. Multi Detector CT, and other imaging modalities, suffer from an inability to distinguish between infiltrating tumor and fibrotic tissue, and therefore there is an immediate need for new non-invasive methods for evaluating response to chemotherapy to support re-staging after neoadjuvant therapy [ 61 ].…”

Peptide Receptor Radionuclide Therapy Targeting the Somatostatin Receptor: Basic Principles, Clinical Applications and Optimization Strategies

“…Historically, a morphological decrease in tumor size is commonly associated with an increase in survival, ultimately reflecting treatment efficacy. At present, the Response Evaluation Criteria in Solid Tumors (RECIST) methodology is still considered the gold standard for response assessment in solid tumors [ 36 ]. However, several PRRT studies have used the Southwest Oncology Group (SWOG) criteria for response assessment in NETs.…”