DISSEMINATED TUMOR-CELLS - DIAGNOSIS, PROGNOSTIC VALUE, PHENOTYPING AND THERAPEUTIC STRATEGY

The incidence of local relapse after complete (RO) resection of solid tumors is largely determined by the skill of the surgeon, whereas meta static relapse in distant organs is caused by pre-or perioperative sys temic dissemination of tumor cells. The presence of individual dissemi nated tumor cells - e.g., in bone marrow as indicator organ - can be d etected by sensitive immunocytochemical and molecular methods and is i ncreasingly considered as a clinically relevant prognostic indicator. In contrast to solid metastases, isolated micrometastatic tumor cells are appropriate targets for intravenously applied anti-cancer therapeu tics because they are easily accessible to macromolecules and immunolo gic effector cells. The majority of these tumor cells appear to be non proliferating (i. e., in the GO phase of the cell cycle), which may ex plain the failure of adjuvant chemotherapy. Adjuvant therapeutic strat egies aimed at quiescent tumor cells are therefore of increasing inter est. This therapeutic rationale has been tested and confirmed in a ran domized clinical trial using antibody 17-1A in patients with non-metas tatic colorectal carcinoma (UICC stage III). The antibody therapy kill s also quiescent tumor cells (''dormant cells'') and is independent fr om a potential chemotherapy resistance of the tumor cells. As treatmen t for minimal residual cancer, the clinical use of antibody therapy co uld be envisaged in conjunction with chemotherapy, applied either in p arallel or sequentially. The aim of this review is to present and disc uss the current state of research in the field of diagnosis and therap y of minimal residual cancer.