[Personalized therapy of gastrointestinal cancers--possibilities and limitations].

The aim of palliative chemotherapy is to increase survival whilst maintaining optimal quality of life for the individual patient. While the best use of traditional chemotherapeutical agents continues to be explored, the introduction of targeted therapies has significantly broadened the therapeutic options. Yet it is interesting to note that the results of current trials did not always confirm the underlying molecular concepts. Recent data have suggested that altered pathways underlie the development of cancer, not just altered genes. Thus an effective therapeutic agent will have to target pathophysiologically relevant signalling networks, rather than individual proteins. This review presents current concepts and problems of cancer treatment, highlighting results from recent clinical trials of colorectal and pancreatic cancer patients and to discuss the current understanding of the underlying mechanisms.