Vascular invasion, perineural invasion, and tumour budding: predictors of outcome in colorectal cancer.

Tumour stage reflected by the AJCC/UICC TNM system is currently regarded as the most powerful prognostic parameter in patients with colorectal cancer. However, additional histopathological markers are required to improve clinical decision-making with respect to follow-up scheduling and administration of adjuvant therapy. In this review we summarize the available literature regarding the prognostic impact of venous and lymphatic invasion, perineural invasion and tumour budding in colorectal cancer. Special emphasis was placed on patients with AJCC/UICC stage II disease, the risk of lymph node metastasis in early cancer and the prediction of local recurrence in rectal cancer. For each of the markers, the different methods of evaluation, implications resulting from different definitions used in previous studies as well as future perspectives are discussed in detail.