To compare the efficacy and safety of tirellizumab combined with anlotinib in the treatment of mss colorectal cancer. To investigate the effective biomarker of anlotinib combined with tiralizumab

This was a multicenter retrospective cohort study to compare the efficacy of tyrosine kinase inhibitor（TKI） combined with immune checkpoint inhibitors(ICIs) versus tyrosine kinase inhibitor alone in the treatment of advanced MSS colorectal cancer. Patients with MSS CRC who have been confirmed by pathology and have relapsed or failed multiline therapy were included in the study. Patients who had received tirellizumab plus anlotinib were considered the combination group, and those treated with anlotinib were classified as the monotherapy group. The efficacy and safety of the two regimens were compared. At the same time, Whole-exome sequencing and transcriptome sequencing were performed on the patients in the response and non-response groups of the combination group to reveal the characteristics of their microenvironment and search for biomarkers related to response.

Inclusion Criteria:

• 18-70 years old
• Patients with mss colorectal cancer who have been confirmed by pathology and have relapsed or failed multiline therapy
• Patients who have been treated with anlotinib monotherapy(12 mg qd, d1-14; 21 days per cycle) or anlotinib(12 mg qd, d1-14; 21 days per cycle)+ tislelizumab(200 mg, once every 3 weeks)
• the presence of at least one measurable target lesion according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1

Exclusion Criteria:

• Patients with other malignant tumors
• Prior treatment with antirotinib, anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137 or anti-CTLA-4 antibodies or any other antibody or drug that specifically targets T cell co-stimulation or checkpoint pathways
• Follow-up was less than 30 days

Patients with advanced MSS type colorectal cancer between November 2020 and May 2023