A novel histologic grading system based on lymphovascular invasion, perineural invasion, and tumor budding in colorectal cancer.

Objective: This study aimed to evaluate the prognostic significance of lymphovascular (LVI), perineural invasion (PNI), and tumor budding positivity in patients with colorectal cancer.

Methods: From January 2008 to December 2011, 3707 consecutive patients who underwent curative surgery for stage I-III colorectal cancer were assessed. These patients were then categorized into four groups based on LVI, PNI, and tumor budding (risk grouping): all negative (n = 1495), 1 + only (n = 1063), 2 + only (n = 861), and all positive (n = 288).

Results: With a median follow-up period of 52 months, the 5-year disease-free survival rates of the risk groups were significantly different in terms of cancer staging (stage I, Stage II, and Stage III: P = 0.006, P < 0.001, and P < 0.001, respectively). In the multivariate analysis, risk grouping was an independent prognostic factor of disease-free survival. Preoperative carcinoembryonic antigen level, tumor size, T category, and N category were independent predictors of LVI, PNI, and tumor budding positivity.

Conclusions: Risk grouping based on LVI, PNI, and tumor budding positivity is a strong predictor of disease-free survival in patients with colorectal cancer.