Circulating tumor cells: mechanisms and clinical significance in colorectal cancer metastasis

Tumors are a major global health problem. As economic development and material standards increase, the incidence and mortality of digestive system tumors have shown an overall rising trend. Among them, colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer death worldwide. Despite advances in molecular biology and therapeutic strategies, tumor metastasis remains the main driver of cancer-related deaths (about 90%). Especially in CRC, the progression of metastasis greatly limits clinical intervention options. Circulating tumor cells (CTCs), a key mediator of hematogenous metastasis, have emerged as a key target for unravelling metastatic mechanisms and developing therapeutic strategies, and are gradually gaining prominence in tumor biology and precision medicine. Therefore, a comprehensive understanding of CTC-mediated mechanisms, especially in the invasion-metastasis cascade of CRC and other cancers of the digestive system, is crucial for early metastasis detection, prevention and identification of new therapeutic targets.