A Prospective Cohort Study of Advanced Colorectal Cancer Treated With Oxaliplatin and Irinotecan.

Inclusion Criteria:

1. Phologically confirmed colorectal adenocarcinoma
2. Treated by oxaliplatin and irinotecan and discontinued due to progression orintolerable drug toxicity
3. ECOG 0-2
4. Predicted survival more than 3 months
5. Estimated by investigators that the main organ function is enough good to tolerate thenext treatment plan.
6. Sign informed consent.
7. Agree to receive survival follow-up

Exclusion Criteria:

1. Previously exposed to regorafenib, furoquintinib, TAS-102, PD-1 inhibitors, ortargeted drugs or immunotherapy for HER2 amplification, BRAF V600E mutation, and NTRKgene fusion.
2. Previously rechallenged or retreated by oxaliplatin or irinotecan after progressionfrom chemotherapy regimens including oxaliplatin and irinotecan.
3. Participate in another interventional clinical study at the same time, unless in thefollow-up stage of intervention study.
4. Proposed to use a treatment regimen containing regorafenib, furquintinib, andtrifluridine, but has any problems obstacling oral drugs, such as inability toswallow, chronic diarrhea and intestinal obstruction et al.
5. Disagree to take contraceptive measures during the study treatment period or within 6months after the end of the study treatment period.
6. Has other primary malignant tumor history, unless non-melanoma skin cancer or lentigomaligna or carcinoma in situ with sufficient treatment and no disease recurrence.
7. Has the history of allogeneic organ transplantation and allogeneic hematopoietic stemcell transplantation.
8. Has concomitant diseases that seriously endanger patient safety or affect patientcompletion of the study.
9. Has other problems that is not suitable for clinical research.