Reconsideration of recurrence and metastasis in colorectal cancer

To discuss recurrence patterns and their significance in colorectal cancer. Preexisting medical hypotheses and the clinical phenomena of recurrence in colorectal cancer were evaluated and integrated. Colorectal cancer recurrence/metastasis consists of two types: recurrence from the activation of dormant cancer cells and recurrence from postoperative residual cancer cells. These two recurrences have their own unique mechanisms, biological behaviors, responses to therapy, and prognoses. For type 1 recurrences, surgical resection should be considered. Type 2 recurrences should be managed systematically in addition to surgical resection. The two types of colorectal cancer recurrence should be evaluated and managed separately.