[Significance of immunohistochemically detectable tumor cells in lymph nodes]

Distant metastasis is mainly determined by the tumor biology, whereas local relapse after complete (R0) resection of solid tumors is largely determined by the effectiveness of the surgeon. The detection of a minimal tumor cell spread in lymph nodes became recently possible by the introduction of sensitive immunohistochemical and molecular methods and is increasingly considered as clinically relevant because of its independent prognostic significance. Furthermore, these tumor cells, compared to solid metastases, are appropriate targets for intravenously applied anti-cancer therapeutics because they are easily accessible for macromolecules and immunologic effector cells. Double staining analyses have demonstrated that the majority of these tumor cells stay in a non proliferating phase of the cell cycle. This phenomenon could be an explanation for the extended latency period ("dormancy") between their primary diagnosis and the occurrence of a subsequent metastatic relapse, and it may furthermore explain the failure of anti-proliferative chemotherapy. Consequently, adjuvant therapeutic strategies, which are directed also against these "dormant" tumor cells are of increasing importance after radical local tumor resection (R0).