Up until a few years ago, organ-conserving kidney tumour surgery was only performed in cases where the patient was threatened with compulsory dialysis if the kidney were to be completely removed (nephrectomy), i.e. mostly in the case of patients who had only one kidney left. In the meantime it can be considered a certainty that partial kidney removal must take precedence over complete removal, even in those cases where there is a healthy kidney present, i.e. if there is no immediate threat of compulsory dialysis. If the site of the tumour allows partial resection, we therefore perform organ-conserving surgery.