Immune checkpoint inhibitors (ICIs) can induce durable responses, even long-term remission, in deficient mismatch repair (dMMR) gastrointestinal (GI) cancers. However, data in racial/ethnic minorities are lacking.


We queried electronic medical records at two affiliate hospitals of Baylor College of Medicine’s Dan L Duncan Comprehensive Cancer Center (Ben Taub Hospital and Baylor-St. Luke’s Medical Center) to identify patients treated with ICIs for dMMR GI cancers (excluding hepatocellular carcinoma) between 2015 and 2022. Descriptive analysis was performed, and cancer-related outcomes were calculated.


Of 64 patients diagnosed with dMMR GI cancers, 39 (61%) were Hispanic, 14 (22%) African-American (AA), and 11 (17%) non-Hispanic white. Cancer site within the GI tract included colorectum (68.7%), stomach (17.2%), biliary tract (7.8%), pancreas (4.7%), and esophagus (1.6%). Of 53 minority (Hispanic and AA) patients who received ICI, 26 had metastatic and 27 had non-metastatic disease. Objective response rates were 38.5% in the metastatic cohort and 66.7% in the non-metastatic cohort. Median overall survival was not reached in either cohort. Restricted mean survival time up to 5 years was not significantly different between non-metastatic patients who underwent ICI treatment plus surgical resection and non-metastatic patients who received ICI without surgical resection (53.7 months vs 50.1 months, p=0.618).


ICI therapy yielded favorable overall and survival rates in Hispanic and AA patients with dMMR GI malignancies. Surgical resection was not associated with improved survival in patients with non-metastatic disease treated with ICIs. Future efforts should focus on comparing outcomes between minority and non-minority patients and defining the role of surgical resection in non-metastatic dMMR GI cancers.