The frequency and clinical significance of neuroendocrine cells within stage III adenocarcinomas of the colon.

BACKGROUND: Although colon carcinomas consisting predominantly of neuroendocrine cells carry a worse prognosis than "routine" colon adenocarcinomas, the clinical significance of scattered neoplastic neuroendocrine cells within a typical colon adenocarcinoma remains controversial. The aim of this study was to document the frequency and clinical significance of neuroendocrine cell expression within a stage-specific group of typical adenocarcinomas of the colon. METHODS: Forty-eight patients with resected stage III adenocarcinomas of the colon were selected from our institutional tumor registry. The pathologic specimens from these patients were reviewed and underwent immunohistochemical staining for chromogranin, a sensitive and specific marker of neuroendocrine differentiation. Long-term (> or = 5 years) clinical outcome was compared with the presence of neuroendocrine cell expression. RESULTS: Twenty tumors (41.7%) stained positively for chromogranin. Twenty-two patients (45.8%) had long-term cancer-free survival, although chromogranin positivity did not correlate with this survival. CONCLUSION: The frequency of scattered neuroendocrine cells within colonic adenocarcinomas is high. This finding does not, however, carry the same adverse prognostic implications for cancer survival as does the presence of true neuroendocrine carcinoma of the colon.