Incidence and prognostic influence of lymph node micrometastases in rectal cancer.

摘要

AIMS: The aim of this study was to determine the rate of lymph node micrometastases and evaluate their prognostic significance in rectal cancer. METHODS: Patients with either Dukes A or B rectal carcinoma who had undergone curative resection by either low anterior resection or abdominal perineal resection between 1991 and 2000 were selected from a prospectively collated database. None of the patients had metastasis at the time of surgery and none received adjuvant or neoadjuvant therapy. A single section from each lymph node was stained with haematoxylin and eosin (H+E) and with CAM 5.2 by immunohistochemistry. Statistical analyses were performed with Chi-square test. RESULTS: A total of 774 lymph nodes with a median of 14 lymph nodes per patient were examined, from a cohort of 56 patients with a median age of 66 years. In the 56 patients in whom lymph node metastases were not detected by haematoxylin-eosin staining, cytokeratin staining was positive in 15 lymph nodes from 10 patients. Nine patients had disease recurrence at a median follow-up of 98 months. The presence of lymph node micrometastases by immunohistochemistry did not predict either disease-free (p=0.44) or overall survival (p=0.63). CONCLUSION: Immunohistochemical staining detects micrometastases in rectal cancer which are not observed with H+E staining. However, no significant relationship was observed between disease relapse and rectal micrometastases detected by immunohistochemistry.