Among the anatomopathological variables related to the prognosis for patients with colorectal cancer, neural invasion remains little studied. OBJECTIVE: To evaluate whether neural invasion in patients with colorectal cancer in Dukes stages B and C could be considered to be an independent prognostic factor, by means of univariate and multivariate analysis. METHODS: Ninety-seven patients who underwent operations with curative intent by the same surgical team were followed up for a minimum period of five years and were studied. Patients who received adjuvant treatment were excluded. The surgical specimens were stained with hematoxylin-eosin (HE) and immunohistochemical techniques for S-100 protein analysis, with the aim of comparing the two techniques for detecting neural invasion. Accuracy, specificity, sensitivity and positive and negative predictive values were analyzed for HE in relation to S-100 protein. Comparison between the incidence of neural invasion and tumor recurrence was made by using the chi-squared test. Survival and disease-free survival were studied by univariate analysis. A significance level of 5% (p £ 0.05) was established for all the tests adopted. RESULTS: The HE technique presented weak ability to detect neural invasion and was inadequate for this analysis in colorectal cancer patients. The survival and disease-free survival curves for patients with neural invasion, investigated by means of immunostaining for S-100 protein, were significantly worse, thus identifying this histological characteristic as having independent prognostic value (p = 0.0003 and p = 0.0002, respectively). There was significantly more tumor recurrence among patients who presented neural invasion (p = 0.0010). CONCLUSION: The results from the present study allow the conclusion that, among colorectal cancer patients, neural invasion was shown to be an independent variable that gave additional prognostic information regarding patients in stages B, C and C2 of the Dukes and Astler-Coller classifications, respectively.
Neoplasms; Colorectal Neoplasms; S 100 Protein; Immunohistochemistry; Prognosis
