Lymph node status has great clinical importance in the management of patients with
colorectal cancer. Several pathologic factors may affect the accuracy of nodal status assessment in this
tumor type. The aim of the present study was to evaluate, in a series of 166 stage II and stage III colorectal
adenocarcinomas, the following pathologic parameters: number of lymph nodes recovered and examined, number of lymph nodes with
metastases, and number of
tumor nodules (
TNs) in the perirectal or pericolic adipose tissue greater or smaller than 3 mm in diameter (
TNs > 3 mm and
TNs < 3 mm, respectively). The prognostic significance of these parameters, as well as of other histopathologic variables, was determined using univariate and multivariate survival analyses. Our results indicate that the examination of a small number of regional lymph nodes may result in understaging of
tumors classified as pN0 (stage II). In addition, our data suggest that
TNs > 3 mm and
TNs < 3 mm represent distinct pathologic entities.
TNs > 3 mm should be considered the prognostic equivalent of
lymph node metastases as recommended by the 1997 TNM classification. In contrast,
TNs < 3 mm probably originate by intravascular or perivascular
tumor extension. Their presence is associated with adverse clinical outcome in stage III patients, regardless of the number of
lymph node metastases.