Preliminary Results of Early Assessment of Response with Perfusion-CT in Patient with Metastatic Renal Cell Carcinoma Treated with Sunitinib

ABSTRACT Introduction The fact that renal cell carcinoma (RCC) is highly dependent of angiogenesis has allowed the development of antiangiogenic drugs (e.g. sunitinib). The assessment of response was based on Response Evaluation Criteria in Solid Tumors (RECIST) but in RCC there is no good correlation between response rate and survival data. So, it is necessary to adopt new image methods that allow a more accurate assessment of response. Objectives To evaluate the pattern of response with perfusion-CT one month after the beginning of the antiangiogenic treatment and correlate with the radiologic evolution. Material and methods Patients (pts) with metastatic RCC and candidates for sunitinib treatment were selected. A volumetric study (21 cm) with perfusion-CT (Flash Definition, Siemens, Erlangen, Germany) was done in these patients before starting the treatment, 1 and 4 months after the antiangiogenic initiation. We defined 6 types of response patterns based on changes in density (D), perfusion (P) and size (S) of the metastases. Results From March 2011 to May 2012, 16 pts were included. The median age was 62 years (43-79), the majority of pts had clear cell carcinoma (n = 13, 81.25%) and good prognosis (n = 14, 87.5%) based on Motzer criteria. We present the results of 1-month evaluation: In 12 pts (75%) a decrease of D and P was observed. This pattern was correlated with a partial response in 8 pts (66.66%). Two pts (16.66%) had a stable disease and two more pts were lost before 4 months CT. This pattern was correlated with a partial response in 8 pts (66.66%). Two pts (16.66%) had a stable disease and two more pts were lost before 4 months CT. The increase of S, associated with a decrease of P and D, was related to haemorrhagic necrosis and it should not be confused with disease progression. This pattern was found in only 2 pts (12.5%). In both cases, the changes in D and P preceded the changes in S. Stability of D, P and S was found in only one patient (6.25%) who had a papillary variant of MRC. An increase of D and P was related with disease progression in one patient (6.25%) and with stability in another case (6.25%). Conclusion The changes in D and P precede the changes in S, and could be predictive of response to antiangiogenic treatment. Long-term follow-up data and a larger series will be presented at the meeting. Disclosure All authors have declared no conflicts of interest.