The Presence of Vascular Mimicry Predicts High Risk of Clear Cell Renal Cell Carcinoma after Radical Nephrectomy

Purpose: Vascular mimicry is a type of tumor cell plasticity. The aim of this study was to determine the prognostic value of vascular mimicry in patients with clear cell renal cell carcinoma. Materials and Methods: We performed a retrospective cohort study in 387 patients with clear cell renal cell carcinoma who underwent radical nephrectomy at Zhongshan Hospital, Fudan University between 2008 and 2009. Pathological features, baseline patient characteristics and followup data were recorded. Vascular mimicry in clear cell renal cell carcinoma tissue was identified by CD31-periodic acid-Schiff double staining. Univariate and multivariate Cox regression models were used to analyze the impact of prognostic factors on recurrence-free survival. The concordance index and the Akaike information criterion were used to assess the predictive accuracy and sufficiency of different models. Results: Positive vascular mimicry staining occurred in 25 of 387 clear cell renal cell carcinoma cases (6.5%) and it was associated with an increased risk of recurrence (log-rank p < 0.001). Incorporating vascular mimicry into pT stage, Fuhrman grade and Leibovich score helped refine individual risk stratification. Moreover, vascular mimicry was identified as an independent prognostic factor (p = 0.001). It was entered into a nomogram together with pT stage, Fuhrman grade, tumor size and necrosis. In the primary cohort the Harrell concordance index for the established nomogram to predict recurrence-free survival was slightly higher than that of the Leibovich model (0.850 vs. 0.823), which failed to reach statistical significance (p = 0.158). Conclusions: Vascular mimicry could be a potential prognosticator for recurrence-free survival in patients with clear cell renal cell carcinoma after radical nephrectomy. Further external validation and functional analysis should be pursued to assess its potential prognostic and therapeutic values for clear cell renal cell carcinoma.