From the surgical point of view it may be helpful to adopt the following guidelines in the treatment of patients with metastatic or locally recurrent colorectal cancer: 1. A gastroenterologist concerned with oncological patients should initiate adequate resectional treatment of the primary tumor. 2. In case of locoregional recurrences, every diagnostic effort (endoscopy, intraluminal ultrasound, angiogram, CT-scan, MRI) should be made to select patients with limited and resectable disease. 3. In patients with liver metastases amenable to surgical resection it is mandatory to rule out extrahepatic disease preoperatively as far as possible. 4. Prognostic factors deriving from tumor-biological data, extent of recurrent disease, and laboratory findings (CEA) must be taken into consideration when the decision whether to operate is to be made. These arguments should also be used to support non-operative treatment in patients with a type of recurrence that cannot be cured by surgery. 5. Postoperatively, all information (intraoperatively detected extrahepatic disease, tumor infiltrated resection margins, CEA not returning to normal levels) should be combined to classify patients according to whether they carry a high risk for a second tumor recurrence and should thus undergo additional treatment. In a "low-risk situation", further follow-up seems to be adequate.