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 em 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 < 0.001). Conclusions: Tumor size at diagnosis is decreasing with time in patients with stage I renal cell carcinoma. These data likely underestimate the proportion of all enhancing renal masses diagnosed at a small size. Patients with small masses may be appropriate candidates for nephron sparing surgery, energy based ablative therapy or active surveillance. Better technologies are needed to determine the diagnosis and prognosis of small enhancing renal masses.