Choi response criteria for prediction of survival in patients with metastatic renal cell carcinoma treated with anti-angiogenic therapies

Abstract

Anti-angiogenic drugs cause a reduction in tumour density (Choi criteria) first and then in size [Response Evaluation Criteria In Solid Tumours (RECIST)]. The prognostic significance of changes in tumour density in metastatic renal cell carcinoma (mRCC) is unknown and was assessed in this study. The prognostic significance of partial response (PR) as opposed to non-response [stable disease (SD) + progressive (PD)] to anti-angiogenic therapy was assessed in patients with mRCC separately for both criteria using the log-rank test and Cox regression models. Both criteria were applied to 35 patients. The response was identical for all eight patients with PR and most patients with PD (10/12) when using the RECIST and Choi criteria. Adding tumour density information, 14 patients with SD were re-categorised as having PR (7), SD (4), and PD (3). Patients with PR (Choi) were progression free significantly longer [hazard ratio (HR) 0.24; 95 % CI 0.10–0.57; P = 0.001] and had better overall survival (HR 0.36; 95 % CI 0.15–0.89; P = 0.026) compared to patients with SD or PD. The predictive value of PR according to RECIST was not statistically significant. In mRCC, the Choi criteria separate prognostic groups better when compared with RECIST. This may allow early discrimination of patients benefiting from continued treatment. • CT is widely used to assess patients with metastatic renal cell carcinoma. • Various algorithms can be applied for tumour therapy control in patients with mRCC. • Follow-up should be based on evaluation of the tumour size and density. • RECIST is based only on tumour shrinkage and might lead to wrong conclusions.