New Insights in Testing and Imaging Techniques for Solid Tumor Response Evaluation

Background: Evaluation of tumor burden plays central roles in cancer care. There remain several aspects of limitations of the conventional Response Evaluation Criteria in Solid Tumors (RECIST). More precise techniques with sufficient standardization and availability are needed for characterizing tumor biological features. Results: This review summarized current techniques of blood testing and imaging techniques on tumor response evaluation. Benefit and limitations of each method were characterized and current trends in application were provided. Conclusion: Peripheral circulating tumor cells (CTCs) and circulating cell-free DNA (ccfDNA) testing techniques overcome the limitations of repeated sampling and bias of histopathological examination, and provide insights of obtaining the whole genome information by blood sampling. Current structural and functional imaging techniques proposed the prognostic value of density, volume, surface area and functional indexes for tumor response evaluation. Further research on distinguishing tumor biological features from the interference of microenvironment and combined multi-parameters analyses based on larger scale data are needed.