External validation of the preoperative Karakiewicz nomogram in a large multicentre series of patients with renal cell carcinoma

Purpose: To perform a formal external validation of the preoperative Karakiewicz nomogram (KN) for the prediction of cancer-specific survival (CSS) using a large series of surgically treated patients diagnosed with organ-confined or metastatic renal cell carcinoma (RCC). Methods: Patient population originated from a series of retrospectively gathered cases that underwent radical or partial nephrectomy between years 1995 and 2007 for suspicion of kidney cancer. The original Cox coefficients were used to generate the predicted risk of CSS at 1, 2, 5, and 10 years following surgery and compared to the observed risk of CSS in the current population. External validation was quantified using meas…