Comment from Henk van der Poel: TKI is currently standard of care in advanced renal cancer. In particular in clear cell cancers responses are impressive, delay in progression substantial, improvement in overall survival noticeable albeit without complete responses. TKI are not without toxicity. In this registry 198/833 (24%) of patients stopped treatment because of toxicity over a median of 4.4 months. Increased age and number of metastases as well as decreased renal function were among the stongest predictors of treatment cessation.