Radiological response evaluation of targeted therapy

The objective assessment of the changes in the tumor burden along with cancer therapy has essential importance. Recently, the quantitative evaluation of the radiological tumor response was undergone several changes. For conventional chemotherapy of solid tumors the standard procedure has been RECIST since 2000. The targeted therapies trigger other pathophysiological changes in the cells than the cytotoxic agents, accordingly the morphological changes show a new picture. Therefore the targeted therapies require a new evaluation system, that takes into consideration not only the tumor size, but other changes as well, the changes of attenuation that corresponds with the proportion of the viable cells. In case of the targeted therapies in substantial clinical was experienced even without signifi cant morphological changes in the tumour size. As a consequence, the traditional, size-based criteria system can underestimate the effi ciency of the new types of treatments. To eliminate this problem new evaluation systems were created taking the tumortypes and treatment protocolls into consideration. The estimation of the early tumor response to targeted therapy also has high importance. In assessment of the response functional imaging methods are used more frequently. The role of PET has already been defi ned in numerous tumortypes, however the determination of the position of some promising functional examinations still require further studies.