1. Urology Department, Instituto de Investigación Sanitaria; Hospital Clinico San Carlos, Universidad Complutense; Madrid; Spain
2. Surgery Department, Instituto de Investigación Sanitaria; Hospital Clinico San Carlos, Universidad Complutense; Madrid; Spain
3. Research and Statistics Unit, Department of Preventive Medicine, Instituto de Investigación Sanitaria; Hospital Clinico San Carlos, Universidad Complutense; Madrid; Spain