The detection of cytokeratins in lymph nodes of Duke's B colorectal cancer subjects predicts a poor outcome.

Objectives: The objectives of this study were to examine the frequency of lymph node micrometastases detected by keratin immunohistochemistry and their relationship with survival behaviour.

Methods: A total of 133 consecutive patients staged as Duke's B, who had curative resection for colorectal cancer (CRC), comprised the study population. Patients who had died of a non-CRC-related cause or who became lost to follow-up were excluded, resulting in an amended population of 100. Study end-points were defined as disease-free survival of 5 years or CRC-related death. Paraffin-embedded lymph node sections were stained with a commercial cytokeratin antibody using a standard avidin-biotin technique.

Results: One quarter of subjects had micrometastases. Fifty-six per cent of subjects with positive lymph nodes had an adverse outcome, compared with 11% of subjects with negative nodes. A highly significant association was found between lymph node cytokeratin expression and mortality in both the univariate (log rank P = 0.0001) and multivariate (Cox proportional hazards P = 0.0123) analysis.

Conclusions: Lymph node micrometastases detected by this inexpensive and simple technique are significantly associated with mortality in Duke's B CRC. This technique may be used to select patients for adjuvant chemotherapy.