Venous invasion as a prognostic factor in colorectal cancer.

Venous invasion as a prognostic factor was evaluated in 124 patients with colorectal cancer. By classifying the patients as having either negative to mild invasion or moderate to marked invasion, a significant correlation was found between the degree of venous invasion and clinicopathological variables such as lymphatic invasion, lymph node metastasis, liver metastasis, and DNA ploidy. Significantly more favorable survival was seen in those with a lower degree of vascular invasion; however, of the six prognosticators analyzed by Cox's proportional hazard model, the only significant factors were depth of invasion and DNA ploidy. Although venous invasion showed no significance, it is still considered a valuable prognostic indicator that is easy and economical to perform.