Is neuroendocrine differentiation a prognostic factor in poorly differentiated colorectal cancer?

BACKGROUND: To determine the prognostic relevance of neuroendocrine differentiation in poorly differentiated colorectal cancer. METHODS: The clinicopathological features and survival of 70 patients with poorly differentiated colorectal cancer were analyzed retrospectively. Chromogranin A and synaptophysin were used as neuroendocrine markers. Patients were followed-up for more than 3 years or until death. RESULTS: Of these 70 patients, 36 showed neuroendocrine differentiation. In univariate prognostic analysis, the patients with lymph node metastasis (P < 0.001), advanced TNM stage (P < 0.001), and neuroendocrine differentiation (P = 0.003) tended to have a poor prognosis. However, only lymph node metastasis was associated with a poor prognosis in multivariate analysis (P < 0.001). Patients with neuroendocrine differentiation were associated with lymph node metastasis (P = 0.006). CONCLUSIONS: Neuroendocrine differentiation in poorly differentiated colorectal cancer was not a direct prognostic factor in these patients. Lymph node metastasis was a direct prognostic factor in these patients. Patients with neuroendocrine differentiation were associated with lymph node metastasis.