Metachronous Metastatic Potential of Small Renal Cell Carcinoma: Dependence on Tumor Size

ObjectivesTo evaluate the association between tumor diameter and clinicopathologic characteristics and metastatic potential in small (≤4 cm) renal cell carcinoma (RCC).MethodsA total of 350 patients with an age range of 24-84 years (median, 54) were included in the study. Patients were categorized according to tumor diameter into 3 groups: ≤2, 2.1-3.0, and 3.1-4.0 cm.ResultsThere were no significant differences in age, sex, histologic type, pathologic stage, and Fuhrman's grade according to tumor diameter. Tumor size did not predict synchronous metastatic disease. Distant metastases at diagnosis were documented in 2.1%, 1.6%, and 0.0% in patients with RCC of diameter ≤2, 2.1-3, and 3.1-4 cm, respectively. During follow-up, recurrence or metastasis developed in 11 patients (3.5%) with a median time to metastasis of 43 months (range 7-104) in 345 patients with localized (N0M0) RCC. Metastases were diagnosed in 2 patients (0.9%) with RCC ≤3 cm and in 9 patients (7.0%) with RCC 3.1-4.0 cm. Significant difference was noted in metastasis-free survival among groups (P = .023). Multivariate Cox proportional hazards model analysis showed that only tumor diameter was an independent predictor of metastasis-free survival (Hazard ratio, 5.344; 95% confidence interval, 1.137-25.127; P = .034).ConclusionsOur findings suggest that risk of metachronous metastasis, but not synchronous metastasis, increases in RCC of diameter >3.0 cm.