Decreasing size at diagnosis of stage 1 renal cell carcinoma: analysis from the National Cancer Data Base, 1993 to 2004

Purpose: The proportion of renal cell carcinoma cases diagnosed at stage I is known to be increasing significantly. We characterized stage I tumors further in terms of tumor size at diagnosis using a large national cancer registry. Materials and Methods: The National Cancer Data Base captures approximately 75% of all newly diagnosed cancer cases in the United States. The database was queried for all adults who were diagnosed between 1993 and 2004 with stage I renal cell carcinoma. Trends were assessed in mean size with time as well as in the proportion of stage I tumors diagnosed at less than 2.0, less than 2.5 and less than 3.0 cm. Results: There were 104,150 patients in the National Cancer Data Base diagnosed with stage I renal cell carcinoma during the study period. A total of 10,279 stage I tumors (9.9%) were less than 2.0 cm, 26,621 (25.6%) were 2.5 cm or less and 39,879 (38.3%) were 3.0 cm or less. Analysis of stage I renal cell carcinoma diagnoses with time demonstrated a statistically significant increase in the proportion of renal masses 3.0 cm or less between 1993 and 2004 (32.5% vs 43.4%). Of tumors 3.0 cm or less the proportion smaller than 2.0 cm increased significantly during the study period from 24.1% in 1993 to 29.4% in 2004. Mean tumor size decreased from 4.1 to 3.6 cm between 1993 and 2004 (p