Choi response criteria for early prediction of clinical outcome in patients with metastatic renal cell cancer treated with sunitinib

BACKGROUND: Because sunitinib can induce extensive necrosis in metastatic renal cell cancer (mRCC), we examined whether criteria defined by Choi might be valuable to predict early sunitinib efficacy.

METHODS: Computed tomography was used for measurement of tumour lesions in mm and lesion attenuation in Hounsfield units (HUs). According to Choi criteria partial response (PR) was defined as > or =10% decrease in size or > or =15% decrease in attenuation.

RESULTS: A total of 55 mRCC patients treated with sunitinib were included. At first evaluation, according to the Response Evaluation Criteria in Solid Tumours (RECIST) 7 patients had PR, 38 stable disease (SD), and 10 progressive disease (PD), whereas according to Choi criteria 36 patients had PR, 6 SD and 13 PD. Median tumour attenuation decreased from 66 to 47 HUs (P< or =0.001). In patients with PR, Choi criteria had a significantly better predictive value for progression-free survival and overall survival (both Ps<0.001) than RECIST (P=0.685 and 0.191 respectively). The predictive value for RECIST increased (P=0.001 and <0.001 respectively), when best response during treatment was taken into account.

CONCLUSION: Choi criteria could be helpful to define early mRCC patients who benefit from sunitinib, but the use of these criteria will not change the management of these patients.