Despite advances in surgical treatment for gastrointestinal tumors, in general, improvements in prognosis could not be achieved; therefore other therapeutical options were evaluated in a multimodal concept. Stage III or II/III disease of colorectal cancer appears to benefit from adjuvant chemo/radiotherapy by reduced relapse and mortality rates. After application of preoperative therapy for locally advanced tumors of the upper gastrointestinal tract and rectum tumor debulking and better local tumor control was achieved resulting in an increased curative resection and survival rate. Surgical procedures and the extent of resection should not be modified in multimodal treatment: the aim must be a complete tumor (R0)-resection.