Types and Rates of COVID-19 Vaccination in Patients With Newly Diagnosed Microsatellite Stable and Instable Non-Metastatic Colon Cancer.

ABSTRACT

Introduction Microsatellite instable (deficient mismatch repair, dMMR) colon cancer is associated with hypermutability and immune infiltration-activation. COVID-19 vaccines stimulate immune-inflammation response. This study aimed to investigate the types and rates of COVID-19 vaccines in patients with newly diagnosed colon cancer and compare it according to the microsatellite status. Methods The study was a single-center case-control study. Patients diagnosed with colon cancer at least three months after the last COVID-19 vaccine (BNT162b2, CoronaVac) dose were included. Patients with dMMR and microsatellite stable (MSS) tumors were defined as cases and controls, respectively, between June 2021 and June 2023. Baseline characteristics and vaccine status between case-control groups were compared as univariable and multivariable. Inflammation markers were compared between MSS+CoronaVac and dMMR+BNT162b2 groups. Results A total of 76 patients were included. The BMI was higher in the MSS group (BMI>25 84.3% vs. 57.9%, p=0.00), and right-sided tumors were more common in the dMMR group (71% vs.46.4%, p=0.00). The dMMR group had a higher BNT162b2 vaccine history than the MSS group (86.8% vs. 63.2%, p=0.01), while there was no difference in CoronaVac history (p=0.32). Significant variables in univariable analysis (BMI, localization, and BNT162b2) were included in multivariable logistic regression. The BNT162b2 vaccine was significantly associated with dMMR status (OR 6.39, 95% CI 1.55-26.26, p=0.01). The dMMR+BNT162b2 group had higher median C-reactive protein (CRP) level (p=0.01), erythrocyte sedimentation rate (p=0.05), and lower lymphocyte/CRP ratio (p=0.04) than the MSS+CoronaVac group. Conclusion Immune infiltration in dMMR colon cancer may interact with COVID-19 vaccine-induced immune activation. Long-term clinical and preclinical studies are needed to confirm these findings.