Chemotherapy in metastatic renal cell carcinoma today? A systematic review

The prognosis of patients affected by metastatic renal cell carcinoma (mRCC) has improved markedly with targeted therapies. Unfortunately, 20-25% of the patients are refractory to treatment at the first response assessment and most patients will acquire drug resistance during the treatment. Moreover, current data on the clinical activity of targeted agents in poor risk or non-clear-cell mRCC patients are inconclusive because of the absence of prospective trials. Therefore, there are still several patients in need of new therapeutic approaches to improve clinical outcomes. Kidney cancer is historically considered resistant to chemotherapy on the basis that the results of phase II trials have not always been promising. We carried out a systematic review of both monochemotherapy and polychemotherapy alone or combined with immunotherapy or targeted agents in mRCC to define the state of the art and to evaluate further clinical research fields. All retrospectives, phase I/dose finding, phase II and phase III studies on chemotherapy in mRCC, published in the literature from January 2003 to November 2012, with at least 20 patients enrolled, were evaluated. Although the results of clinical trials have often been disappointing, in selected cases of mRCC, chemotherapy may have a promising antitumor activity, particularly when there are sarcomatoid differentiation features, or in highly progressive disease where the combination of doxorubicine plus gemcitabine or capecitabine has yielded interesting results. Chemotherapy may play a role in mRCC, whereas targeted agents and immunotherapy have not yielded durable and satisfactory results; further studies are needed.