Coded Tumor Size May Be Unreliable for Small Metastatic Renal Cancers in the Surveillance, Epidemiology, and End Results Dataset

Coded primary tumor sizes in the April 2006 release SEER dataset for metastatic renal tumors <1.8 cm from 1998 to 2003 were often inaccurate. Verification of tumor size in this subset was essential to insure data accuracy and quality of research. Researchers should recognize potential limitations of population-based cancer registries.