Abstract
Background and aim The depth of tumor invasion is currently the only reliable predictive risk factor
for lymph node metastasis before endoscopic treatment for colorectal cancer. However,
the most important factor to predict lymph node metastasis has been suggested to be
lymphovascular invasion rather than the depth of invasion. Thus, the aim of this study
was to investigate the predictive relevance of lymphovascular invasion before endoscopic
treatment.
Methods The data on pT1 colorectal cancers that were resected endoscopically or surgically
from 2007 to 2015 were retrospectively reviewed. The cases were categorized into two
groups: positive or negative for lymphovascular invasion. The following factors were
evaluated by univariate and multivariate analyses: age and sex of the patients; location,
size, and morphology of the lesion; and depth of invasion.
Results The positive and negative groups included 229 and 457 cases, respectively. Younger
age (P < 0.01), smaller lesion size (P = 0.01), non-LST (LST: laterally spreading tumor) (P < 0.01), presence of depression (P < 0.01), and pT1b (P < 0.01) were associated with lymphovascular invasion. In multivariate analysis, younger
age (comparing patients aged ≤ 64 years with those aged > 65 years, OR, 1.81; 95 %CI,
1.29 – 2.53), presence of depression (OR, 1.97; CI, 1.40 – 2.77), non-LST features
(OR, 1.50; CI, 1.04 – 2.15), and pT1b (OR, 3.08; CI, 1.91 – 4.97) were associated
with lymphovascular invasion.
Conclusion Younger age, presence of depression, T1b, and non-LST are associated with lymphovascular
invasion. Therefore, careful pathological diagnosis and surveillance are necessary
for lesions demonstrating any of these four factors.
