Prospective evaluation of prognostic factors in patients with colorectal cancer undergoing curative resection

Streak type, defined by the presence of white streaks at the advancing margin of tumor invasion; focal dedifferentiation, seen as undifferentiated cancer cells with an infiltrative pattern at the invasive front; and perineural invasion have been demonstrated to be prognostic factors in patients with colorectal cancer. We performed a prospective study to examine the usefulness of these features as prognostic factors.

We reviewed a total of 391 patients who underwent curative surgery for colorectal cancer between May 1997 and June 1999. Of these, 50 patients with multiple cancers were excluded, and a total of 341 patients were finally entered into the study.

Of the prognostic factors investigated, depth of invasion, lymph node status, lymphatic invasion, venous invasion, growth type, streak type, focal dedifferentiation, and perineural invasion were significant prognostic factors in univariate analysis. In multivariate analysis, lymph node status, depth of invasion, and perineural invasion were significant prognostic factors. The survival of patients with perineural invasion was significantly poorer than that of patients without perineural invasion in both stage II and III cancer.

Perineural invasion status can be used to facilitate the selection of colorectal cancer patients for adjuvant chemotherapy and should be described in routine pathology reports.