Character of the invasive margin in colorectal cancer - Does it improve prognostic information of Dukes staging?

PURPOSE: The clinical significance and prognostic value of the histopathologic parameters used in both the Dukes and Jass classifications were evaluated to select those with an independent effect on survival after radical surgery for colorectal cancer. METHODS: The depth of local spread (Limited to the bowel wall or extended beyond it), the number of metastatic lymph nodes (none, 1-4, more than 4), the character of the invasive margin (pushing or infiltrating), and the presence or absence of conspicuous peritumoral lymphocytic infiltration were assessed in 235 patients who had undergone radical resection for colorectal cancer. The influence of these variables on survival was studied by univariate and multivariate analysis. RESULTS: No significant difference in survival was found between patients with conspicuous peritumoral infiltrate and those without it; moreover, multivariate analysis failed to show any independent prognostic value far either lymphocytic infiltration or depth of local invasion, Hom ever, the character of the invasive margin and the number of metastatic lymph nodes were identified as the only variables with any independent importance on survival. Based on these data, a new prog prognostic model may be proposed; it uses the character of the infiltrative margin as a discriminating factor among patients within the lymph node-negative (Dukes A and B stages) and lymph node-positive (Dukes C1 and C2 subsets) groups. A good prognosis for Dukes A, B, and C1 patients was associated with pushing tumors; C1 and C2 patients with infiltrating rumors had a poor prognosis. On the whole, the new prognostic model has allowed for the placement of 59.6 percent of our patients into groups that provide a confident prognosis. The clinical outcome of Dukes A and B patients with infiltrating tumors is still uncertain. CONCLUSIONS: The character of the invasive margin is an important prognostic factor in colorectal cancer, The association of this parameter with the traditional Dukes classification may provide additional useful prognostic information and aid in the selection of those patients who could most benefit from adjuvant therapy.