Circulating tumour cells in colorectal cancer

Background: The detection of circulating tumour cells (CTC) in blood sample in patients with early or advanced colorectal cancer has a potential prognostic value. Methods: The challenge of CTC detection is related to the requirement of high sensitivity combined with high specificity method. CTCs detection can be distinguished between indirect and direct methods. The former ones are based on the recognition of tissue-, organ- or tumour-specific markers by immuno-histochemistry (indirect immuno-mediated methods) or (real-time) RT-PCR (indirect molecular methods), whilst the latter are related to CTCs selection based on the physical properties of density and sizes. Ongoing and future isolation by size of epithelial tumour cells (ISET) developments concerning automated image analysis on the filter and transmission of high definition images through the web for 'on line' cytopathological consultations are aimed to speed up the work of cytopathologists on CTC/ circulating tumour microemboli (CTM) detection. Conclusions: CTC detection in colorectal cancer (CRC) correlates with pathological stage and clinical outcome in particular in those patients with advanced disease. CRC CTC level before and after CT are an independent prognostic factor for progression-free and overall survival. The positive prognostic value of complete clearance CTC after surgery may be useful to select patients for adjuvant chemotherapy. © 2008 Elsevier Ltd. All rights reserved.