Prognostic Significance of Macroscopic Appearance in Clear Cell Renal Cell Carcinoma and Its Metastasis-Predicting Model.

Prognostic significance of macroscopic appearance of clear cell renal cell carcinoma (ccRCC) has not yet been studied. This study aimed to define the prognostic significance of macroscopic appearance and to propose a prognostic model for post-operative metastasis in ccRCC. A total of 1,025 patients with ccRCC were analyzed for the development dataset. A separate cohort of 399 such patients was used as an external validation dataset. Macroscopic appearances were initially divided into four groups, but were later divided into two groups: a simple nodular group (700 cases, 68.3%) and an irregular outline group (325 cases, 32.7%). During the 66.1-month mean follow-up period, 98 patients (9.6%) developed metastasis. Univariate analysis revealed that metastasis was associated with older age, radical nephrectomy, larger tumor size, higher tumor grade and stage, and the irregular outline group. On multivariate analysis, age, tumor size, and macroscopic appearance remained as independent prognostic factors. These factors were used to build a prognostic model, which divided into three risk groups. The probabilities of 5-year metastasis-free survival in the low-, intermediate-, and high-risk groups were 98%, 83%, and 53%, respectively. The results showed prognostic significance of macroscopic appearance in ccRCC and propose a prognostic model to guide post-operative management of patients with ccRCC.