Evaluation of the response to therapy of neoplastic lesions

The introduction of an evaluation standard for the response to therapy of neoplastic lesions is necessary not only for the standardisation of clinical research protocols, but also to allow the objective and transferable management of the oncology patient in routine clinical practice. The international criteria that define how to evaluate a neoplastic disease and to determine its response to treatment were first introduced in the 80s by the WHO and have been recently updated with the new RECIST criteria defined by broad consensus of European and U.S. oncology organisations and published in 2000. The new criteria, especially those related to lesion measurement are substantially different from the previous criteria, they are simpler and easier to use, but present some problems that should be brought to the attention of radiologists who must adjust them with the common sense and balance of judgement resulting from our practice. These problems refer above all to certain types of lesions (such as cystic, bone and nodal metastases), to the method for measuring the maximum diameter, to the use of contrast agents and to the frequency of follow-up examinations, with consequent effects on radioprotection and workloads. In any case, the radiologist who examines a patient with neoplastic lesions and compares the examination results with previous images, should make sure the report does not contain vague language, that the maximum diameters of the lesions are always indicated and that any morphological and/or contrast enhancement changes are described: the report should enable clinicians to make a complete evaluation of the condition and of disease progression, for a global management of the oncology patient.