[Biological characterization of metastatic renal cell carcinoma]

Renal cell carcinoma is the sixth leading cause of death for cancer in industrialized countries and one third of patients has metastases at the time of diagnosis. The three most common histological types of renal cell carcinoma are: clear cell carcinoma (70-80%), papillary carcinoma (10-15%) and chromophobe cell carcinoma (5%). The location of metastases vary according to histotype: lung metastases are found in 53.6% of cases in patients with clear cell carcinoma, whereas in patients with papillary carcinoma or chromophobe cell carcinoma in 33.3% and 28.2% of cases, respectively. In contrast, chromophobe cell carcinoma is more often associated with liver metastases (33.3%), compared with clear cell carcinoma (9.7%) or papillary carcinoma (18%). Patients with renal cell carcinoma metastatic to a single organ have a better prognosis than patients with metastases in multiple organs and the overall survival of patients with localized lung metastases is similar to that of patients with exclusive bone metastases. The overall survival, therefore, is related more to the number of organs involved by metastasis rather than by the location of metastases. The widespread use of abdominal non-invasive diagnostic procedures, with an incidental finding of renal cell carcinomas still in a low stage of development, and the refinement of surgical techniques for resection of metastatic disease (metastasectomy) have led to only a slight improvement in overall survival in the last 30 years for the resistance of the tumor to common chemo-radiotherapy. Surgery remains the best therapeutic option and a rising in cutting-edge molecular therapies is strongly needed.