Characteristics of lymph node metastases defining the outcome after radical cystectomy of urothelial bladder carcinoma

Objective: The aim of this study was to identify clinicopathological variables associated with the clinical outcomes of patients with lymph node metastasis-positive urothelial bladder carcinoma after radical cystectomy. Methods: Forty-six patients who underwent radical cystectomy without preoperative chemotherapy and had histologically proven nodal metastasis were included in the study. The status of lymph nodes and primary lesion was analyzed in terms of disease-specific survival and recurrence-free survival. Results: The 5-year disease-specific survival and recurrence-free survival for the 46 patients overall were 41.3 and 32.2%, respectively. Univariate analysis showed that pN status, the total number of involved lymph nodes, lymph node density and extranodal invasion were statistically significant variables predictive of disease-specific survival. Multivariate analysis revealed that the total number of involved lymph nodes, extranodal invasion and diameter of the metastatic lesion were statistically significant variables predictive of disease-specific survival. Interestingly, the diameter of metastatic lesions was inversely correlated with poorer survival. Patients with large (≥10 mm) metastatic lesions and no extranodal invasion (expansive growth) had significantly better disease-specific survival than those with multiple small (<10 mm) metastatic lesions and no extranodal invasion (highly spreading) (P = 0.0156) or those with extranodal invasion (infiltrative growth) (P = 0.0181). Conclusions: Our data indicate that the clinical outcome of node-positive patients is not only stratified according to the tumor burden reflected in the total number of involved lymph nodes, but also affected by tumor biology including invasiveness and potential for metastasis, which is reflected in pathological characteristics such as extranodal invasion and the diameter of metastatic lesions.