Colorectal cancer surgery: what is evidence based and how should we do it?.

Evidence-based medicine was first defined by Sackett as 'the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients'. This requires good quality studies with a high level of proof. However, these studies are often lacking in colorectal surgery. Nevertheless, the topics on which there is general agreement will be discussed. There is now good evidence that the laparoscopic approach is at least equivalent in oncological terms to the conventional open approach in colonic surgery. The question, however, remains unanswered for rectal cancer surgery, which is technically more demanding. Although there are no randomized studies, the introduction of total mesorectal excision for rectal cancer has achieved a major reduction in local recurrence and has been adopted as the gold standard by all colorectal surgeons. Extending this concept to colonic cancer surgery is currently under discussion. The different types of reconstruction in sphincter-preserving surgery which achieve a better functional result than straight anastomosis, including colonic pouch, transverse coloplasty and side-to-end anastomosis, will be discussed. The benefit of temporary fecal diversion in low anastomosis has now been demonstrated with a good level of evidence. The technique of abdominoperineal resection has evolved in the last years and now aims at obtaining a cylindrical specimen, which has resulted in a significant reduction of the local recurrence rate. In early rectal cancer, the technique of local resection has been improved by the introduction of transanal endoscopic microsurgery.