Purpose: We determined the relationship between the prevalence of metastasis at presentation and cancer specific mortality with tumor size in renal cancer cases using a large cancer database.
Materials and methods: The Surveillance, Epidemiology and End Results data set was analyzed for renal tumors diagnosed from 1998 to 2003. A total of 24,253 patients were included. The prevalence of metastasis and cancer specific survival as a function of tumor size were evaluated using linear and nonlinear curve fitting methods. Metastatic cases with tumors 2.5 cm or less were individually reconfirmed case by case for accuracy.
Results: Increasing tumor size correlated with a higher prevalence of metastasis at diagnosis (range 1.4% for tumors 1 cm or less to 50.9% for tumors greater than 15 cm). Five-year cancer specific mortality in treated patients was also closely related to tumor size (range 3.5% for tumors 1 cm or less to 50.9% for tumors greater than 15 cm). In each instance the relationship was sigmoidal rather than linear and it was best modeled using a quadratic function. The most rapid increase in the prevalence of metastasis and mortality was noted for tumors 4 to 12 cm. In treated patients with tumors 1 cm or less, 1.1 to 2, 2.1 to 3 and 3.1 to 4 the prevalence of metastasis at diagnosis was 1.4%, 2.5%, 4.7% and 7.4%, and the 5-year cancer specific mortality rate was 3.5%, 3.8%, 4.1% and 5.3%, respectively.
Conclusions: In cases of renal cancer the prevalence of metastasis at presentation and 5-year cancer specific mortality increase in a nonlinear sigmoidal relationship with tumor size.