Surgical resection for residual lesions could significantly improve the prognosis in metastatic colorectal cancers (CRCs) after systemic treatments, yet the necessity of resecting residual lesions after immune checkpoint inhibitions (ICIs) remains controversial in mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) diseases. We retrospectively enrolled recurrent or metastatic dMMR/MSI-H CRCs who received surgerys from Sun Yat-sen University Cancer Center. Patients without disease progression after at least 2 cycles of ICIs were included. Demographic and clinicopathological data were collected and analyzed. Relapse-free survival (RFS) after surgery were analyzed.

Inclusion Criteria:

1. pathologically confirmed CRC with measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1)20;
2. definite pathological or radiological evidence of recurrent or distant metastasis;
3. received at least 2 courses of ICIs;
4. confirmed as dMMR by immunohistochemical method or MSI-H by polymerase chain reaction or next-generation sequencing;
5. receiving therapeutic surgical treatment for residual lesions or tumor sites and achieving no evidence of disease (NED) ;
6. no progression within the duration of preoperative ICIs

Exclusion Criteria:

-

The patients with recurrent or metastatic dMMR/MSI-H CRC who received PD-1 inhibition-based ICIs and subsequently underwent surgery from January 1, 2017 to July 1, 2023 at Sun Yat-sen University Cancer Center were entrolled.