摘要: 1 Summary The 5-year-survival rates of surgically treated patients are varying and depend on UICC stages/substages with remarkable variations in between published reports, surgical hospital units, individual surgeons, and continents. These variations may be due to surgical techniques, training status, hospital and individual case volume, but also on referral patterns, and statistical evaluation methods. Survival time and cure rates are significantly improved by modern adjuvant chemotherapy in colon cancers UICC Ⅲ and in substages of UICC Ⅱ (e.g. UICC Ⅱ B) by 5%-16%, and adjuvant radiochemotherapy in rectal cancer by 10%-14% when compared to surgical controls. In three modern colon cancer trials standard adjuvant chemotherapy was further improved by increasing the survival rates, e.g. from 59% to 71% in stage Ⅲ and IIB patients. In rectal cancer neoadjuvant radio(chemo)therapy decreases local relapse rates vs. postoperative adjuvant radio(chemo)therapy. Since surgery in rectal cancer has also been significantly improved by total mesorectal excision (TME) and better surgical training, the indications and methods for multimodal therapy have changed from UICC Ⅱ+Ⅲ to more individual criteria. Molecular and genetic factors, such as thymidylate synthase (TS), microsatellite instability (MSI) or loss of chromosome 18q/DCC might have an independent impact on prognosis in the spontaneous course, but could also help to individually select colon and rectal cancer patients and treatment protocols for multimodal therapy. Thus, surgery and multimodal therapy has become very complex, needs regularly be updated in competent reviews, and should be conducted in specialized centers of multi-and interdisciplinary excellence.