Circulating tumor cells (CTCs) in the blood play an essential role in cancer metastasis. Hence, the detection of CTCs and subsequent analysis can potentially revolutionize the cancer care ranging from screening, diagnosis, monitoring, to drug selection and so on. In the past decade, many methods using magnetic beads (CellSearch), filtration (RareCelletc), or flow cytometry have been developed but all of them have the shortcomings from low sensitivity, low purity, to unable to retrieve cells for downstream molecular analysis and cell culture. Recently, a biomimetic affinity based microfluidic platform has overcome abovementioned technical challenges. Importantly, by using only 2 ml of peripheral blood, Sinica's team has shown that the enumeration of CTCs increases with the CRC disease progression, where the mean CTC counts are 3, 15, 29 and 60 per ml for the stages I, II, III and IV, respectively. The results imply that monitoring CTC enumeration serially may serve as a prediction marker to identify the CRC patients with high probability of recurrence. The aims of this study are toestablishing CTC platform standard operation protocol (SOP) that leads to certification of ISO 13485 and to establish CTC criteria and evaluate its prediction power of early detection of colorectal cancer recurrence.