The aim of the study is to evaluate if it is possible to mark with a wire colorectal hepatic metastases after complete response to a neoadjuvant chemotherapy.Primary the investigators want to investigate if the wire marking is a possibility to mark respectively to identify these lesions. Further the investigators want to evaluate how many patients with complete radiologic have complete histologic response in their specimen respectively in how many specimens in the definitive histology tumor cells are visible.

Colorectal Cancer is most common in western countries. In 2007 in Austria 4462 new colorectal cancers were diagnosed. The most common place of metastasis is the liver. Approximately 15% of patients have metastasis at time of diagnosis of primary tumor and further 50% will develop metastases in the further course of the disease.However only 10-25% of patients are candidates for liver resection. New chemotherapeutics, new targeted therapies with monoclonal antibodies and better surgical techniques improved response rates, resection rates and overall survival. Owing to improved response rates metastases in the liver partially respectively completely disappeared, so that these lesions are not more visible in apparative diagnostic like CT-scan and MRI.

The question is now what to do with this patients? In the literature there is no evidence how to manage these patients. Conservative management would lead to a reoccurrence of metastases in the liver. On the other side surgical management is difficult, because metastases are preoperatively and intraoperatively not visible and resection is only possible with the removement of greater amounts of healthy tissue.

The computer tomography-guided wire marking of the metastases in the liver is a possibility to overcome these problems. All patients with complete radiologic response of metastases in the liver and metastases ≤ 1 cm are included in the study (RECISTE-Criteria). On day of surgical procedure patients will brought to interventional radiologist and based on computer tomography images before neoadjuvant chemotherapy the lesions will be marked computer tomography-guided with a wire(X-Reidy Breast Lesion Localization Needle, Cook Medical). The wire is placed percutaneously and under antibiotic prophylaxis. After the marking procedure, the patient is brought into the operating room to resect the metastases in the liver.

Inclusion Criteria:

• Histologic verified cancer of the colon and rectum with metastases into the liver
• Neoadjuvant chemotherapy with complete radiologic response of metastases in apparative diagnostic respectively metastases with a diameter ≤ 1 cm.
• Technically Resectability
• Age ≥ 18 Years
• Written informed consent

Exclusion Criteria:

• Age < 18 Years
• Technically Irresectability
• Neoadjuvant chemotherapy and response of metastases, however with a diameter > 1 cm.

Tertiary care clinic