[Monitoring of metastatic renal cell carcinoma--standards and challenges].

The introduction of targeted therapies has led to a novel situation regarding monitoring of metastatic renal cell carcinoma (mRCC): patients treated with these new drugs have a significantly longer life expectancy than just a few years ago. In order to maximize the treatment benefit, new demands have come up on the assessment of tumor progression: timing and interpretation of imaging studies are crucial for optimal therapeutic management. Detailed knowledge of the new compounds' mode of action is important as it is different from that of classic cytotoxic drugs. The RECIST criteria constitute the standard for evaluation. Following recommendations made by the German Cancer Society's (DKG) interdisciplinary task force, targeted therapies should strive for a sufficient treatment duration in each line of therapy in order to achieve the best therapeutic outcome. Treatment is continued until clinical progression occurs. Assessing therapeutic efficacy with adequate imaging techniques 6-9 weeks after the beginning of therapy is recommended. Subsequent follow-up examinations should be repeated using identical imaging modalities every 2-3 months. For cyclically applied drugs such as Sunitinib, examinations should be carried out at identical time points within the treatment cycle.