Imaging Criteria for Tumor Treatment Response Evaluation

The evaluation of the tumor response to therapy represents a significant and continuously expanding part of the radiological practice, especially in services with oncological departments. The modern imaging modalities are valuable tools for objective quantitative assessment of the result of new antineoplastic therapeutic schemes. The standardization of criteria provides common endpoints for clinical trials, permits comparisons between different studies, facilitates the formation of more effective therapies and accelerates the procedure of approval of new drugs by the authorized organizations. The most widely used imaging criterion of a successful therapy is the shrinkage of the neoplastic lesions in a certain patient. It represents the typical endpoint in phase II trials, targeted to the preliminary evaluation of the effectiveness of new antineoplastic drugs in order to decide if these have to be further tested in wider clinical studies. Also, the objective criterion of “tumour shrinkage” and the duration of “progression free survival” (PFS) represent the commonest endpoints for phase III clinical trials, aiming to assess the benefit of applying one or more therapeutic schemes in specific patient populations.