The aim is to conduct a prospective multicentre randomised study comparing two different control regimens after resection for colorectal cancer stage II - III. Follow-up after surgery for colorectal cancer is a controversial issue. The reasons for follow-up are: to obtain a better overall survival, for scientific purposes and/or for psychological reasons and/or as quality assessment. Meta-analyses of randomised controlled studies have lately shown that a beneficial effect on the overall mortality could be found with intense follow-up compared to sporadic. This study compares the regimen of CT-scan or MR scan of the liver, control of the carcinoembryonic antigen (CEA), and CT-scan or X-ray of the lungs in two groups with either control after 12 and 36 months, or after 6, 12, 18, 24, and 36 months. The efficacy parameters are total and cancer-specific mortality.

The aim is to investigate the efficiency of two follow-up programs after radical surgery for colorectal cancer. Colorectal cancer attacks between 3-5% of the European population during their lifetime, and about 75% of these will have potential curative surgery performed. Follow up after surgery is costly and time consuming for both patients and the Health Care Systems. The intensity of follow up as well as the methods employed vary tremendously from center to centre and from country to country. Until recently the scientific documentation for the cost-effectiveness of follow-up was very sparse, but recent compiling of data indicates that intense follow up can save lives as compared to sporadic follow-up at an acceptable cost. However, the optimal follow-up intervals and the best methods are unknown. Previous results indicate that scanning of the liver and measuring of the tumor-marker CEA may be a way forward. A prospective randomised multicenter study in centers from Denmark (approx. 15), Sweden (approx. 20), Poland (approx. 6), Hungary (approx. 2) and perhaps The Netherlands and UK is starting in 2005 after basic work with protocols, ethical committees now has been finished. This basic work was supported by the Nordic Cancer Union with a grant of 25,000 EUROS. The patients will be randomised to follow-up with CEA, multislice CT scan of the liver and X-ray of the lungs, either 12 and 36 months after surgery or 6, 12, 18, 24 and 36 months after surgery. If recurrence is detected, the patient will be offered the best available treatment either as repeated surgery with curative intent or palliative oncological treatment. Data will be collected electronically via the internet to an already constructed database. The primary efficacy parameter is 3 and 5 years overall and cancer-specific survival. It is planned that recruitment will be at least 2,500 patients, which is feasible in 2 years.

Inclusion Criteria:

• Radical surgery (R0-resection) for colorectal adenocarcinoma - with or without adjuvant treatment
• Age < 75 years
• Provision of written informed consent for participation
• "Clean colon" verified by perioperative barium enema or colonoscopy last 3 months post-surgery
• Tumour stage: II-III (Tany N1-2 M0, T3-4NanyM0, Dukes´ B - C)

Exclusion Criteria:

• A clinical diagnosis of HNPCC (non hereditary polyposis colorectal cancer) or FAP (familial polyposis coli)
• Local resection for colorectal cancer (e.g., TEM-procedure)
• Life-expectancy less than 2 years due to concurrent disease (e.g., cardiac disease, terminal multiple sclerosis, liver cirrhosis)
• Inability to provide informed consent or refusal to do so
• Inability to comply with the control or intense follow-up program
• Participation in other clinical trials interfering with the control-programs
• Previous malignancies (except for non-melanoma skin cancer)