Metastatic non-clear cell renal cell carcinoma: current therapeutic options

Non-clear cell (ncc) renal cell carcinoma (RCC) accounts for approximate to 25% of all patients with metastatic RCC. It is refractory to standard immuno(chemo)therapy and, to date, no specific trials have been reported to evaluate the efficacy of novel targeted drugs in the different subtypes of metastatic nccRCC. We review all available data from subgroup analyses of the global sorafenib and sunitinib expanded access programmes, current phase-III trials, and smaller multi- and single-centre studies focusing on the activity of targeted agents in these specific and rare RCC subtypes. Both sorafenib and sunitinib have significant activity in metastatic nccRCC, but the efficacy of each agent seems to vary between different nccRCC forms. Preliminary clinical data for temsirolimus appear to be promising but more extensive and long-term data are awaited. With the advent of novel therapeutic options, specific controlled multicentre trials are urgently needed to define their exact value and efficacy for treating the historically resistant nccRCC forms. The medium-term aim should be to tailor the most advantageous therapy for each patient with respect to his/her individual RCC subtype and physical condition.