The Loss of Radiographic Enhancement in Primary Renal Cell Carcinoma Tumors Following Multitargeted Receptor Tyrosine Kinase Therapy is an Additional Indicator of Response

Intratumoral changes in computed tomography enhancement after receptor tyrosine kinase inhibition correlate with primary tumor response, and may be a useful adjunct to the standard response evaluation criteria in solid tumors (RECIST criteria) in assessing response to therapy. Prospective studies evaluating antiangiogenic agents should explore intratumoral changes in contrast enhancement as part of response criteria, and examine the effect of intratumoral changes on survival-based outcomes.