Advanced colorectal cancer: ESMO Clinical Practice Guidelines for treatment.

Clinical or biochemical suspicion of metastatic disease should always be confirmed by adequate radiological imaging [usually a computed tomography (CT) scan or alternatively magnetic resonance imaging (MRI) or ultrasonography]. Fluorodeoxyglucose-positron emission tomography (FDG-PET) scan can be useful in determining the malignant characteristics of tumoral lesions, especially when combined with CT scan. FDGPET scan is especially useful to characterize the extent of metastatic disease when the metastases are potentially resectable. Histology of the primary tumour or metastases is always needed before chemotherapy is started. For metachronous metastases histopathological or cytological confirmation of metastases should be obtained, if the clinical or radiological presentation is atypical or very late after the initial diagnosis of the primary tumour. Resectable metastases do not need histological or cytological confirmation before resection because of a low chance of seeding. Evaluation of the general condition, organ function and concomitant non-malignant diseases determines the therapeutic strategy for patients with metastatic CRC. determination of the treatment strategy