The new Web-based DB system was established to collect basic demographic and clinicopathological characteristics of a large cohort of patients with RCC in Korea. This project was approved by local ethics committee at Seoul National University Bundang Hospital (IRB number: B1202/145-102). The data included basic demographic (such as age, gender, height, and weight) and clinicopathological characteristics (such as clinical stage, perioperative parameters, pathological stage, Fuhrman nuclear grade and survival data) (Tables 1 , 2 , 3 , 4 , 5 ). AJCC cancer staging manual was used for TNM staging [15 ]. Private information (such as resident registration number and hospital ID number) was excluded to protect the patients' personal information.
Data from a total of 6,849 patients were collected from 8 tertiary care hospitals that agreed to participate in organizing KORCC study group as of 1 July 2015. These hospitals were Chonnam National University Hwasun Hospital (308 cases), Chungbuk National University Hospital (178 cases), Korea University Anam Hospital (105 cases), Kyungpook University Medical Center (890 cases), National Cancer Center (618 cases), Seoul St. Mary's Hospital (883 cases), Seoul National University Bundang Hospital (1,440 cases) and Seoul National University Hospital (2,427 cases). Data were collected for the management of renal masses of all tumor stages (pT1-4, N0-2, M0-1) at the Department of Urology at each hospital from 1990 to present (time frame varies among hospitals due to differences in their own DB collections). Hospitals have contributed to the database by adding all consecutive patients until now.
We analyzed the data of patients who underwent surgical treatments. They were compared with those of previous international studies to characterize Korean RCC. Some data were excluded from the analysis due to insufficient or missing variables.
Data from a total of 6,849 patients were collected from 8 tertiary care hospitals that agreed to participate in organizing KORCC study group as of 1 July 2015. These hospitals were Chonnam National University Hwasun Hospital (308 cases), Chungbuk National University Hospital (178 cases), Korea University Anam Hospital (105 cases), Kyungpook University Medical Center (890 cases), National Cancer Center (618 cases), Seoul St. Mary's Hospital (883 cases), Seoul National University Bundang Hospital (1,440 cases) and Seoul National University Hospital (2,427 cases). Data were collected for the management of renal masses of all tumor stages (pT1-4, N0-2, M0-1) at the Department of Urology at each hospital from 1990 to present (time frame varies among hospitals due to differences in their own DB collections). Hospitals have contributed to the database by adding all consecutive patients until now.
We analyzed the data of patients who underwent surgical treatments. They were compared with those of previous international studies to characterize Korean RCC. Some data were excluded from the analysis due to insufficient or missing variables.
