Fluorouracil-based chemotherapy is the standard treatment for stage IV colorectal cancer patients. However, the effects of chemotherapy remains limited. Patient-derived tumor organoids are increasingly used as tools for drug test and predicting drug response in the clinic, and have been showed to faithfully predict clinical outcomes of patients with CRC. A prospective clinical trial is needed to validate whether the in vitro sensitivity to chemotherapy regimens in organoids drug test is associated with a longer PFS in stage IV colorectal cancer.