Intravascular emboli is an independent risk factor for the prognosis of stage III colorectal cancer patients after radical surgery.

Lymphovascular emboli is a prognostic factor in stage II CRC, but the significance of intravascular emboli (IVE) in stage III is unclear. Data from consecutive stage III CRC patients receiving radical surgery between January 2009 and November 2014 were retrospectively collected. The expression of CD133 was tested by immumohistochemical (IHC) staining. The potential prognosis risk factors were tested using univariate and multivariate survival analyses. IVE was significantly associated with CD133 expression (P < 0.001), gross tumor morphology (P = 0.001), histologic type (p < 0.001), lymph node status (pN) (p < 0.001), sub-class of stage III (p = 0.001), and serum CA199 level (p = 0.022). IVE, CD133 expression and lymph node status (pN) were independent risk factors for overall survival (OS) (p < 0.001, p = 0.003, and p = 0.008, respectively) and disease-free survival (DFS) (p < 0.001, p = 0.004, and p = 0.007, respectively) in stage III CRC. IVE might be an independent risk factor for the prognosis of stage III CRC patients after radical surgery. IVE might express a cancer stem cell (CSC) phenotype.