Impact of breakthrough SARS-CoV-2 infections on vaccinated patients with colorectal cancer: A retrospective cohort study.

Abstract

e15656 Background: Cancer patients are vulnerable to severe SARS-COVID outcomes due to the immunosuppressive effect by both the inherent nature of cancer and its diverse therapeutic interventions. Although COVID-19 vaccines have shown efficacy, their effectiveness appears to decrease among cancer patients. We hypothesize that colorectal cancer (CRC) patients are at a higher risk of breakthrough COVID-19 infection and severe outcomes. Methods: We conducted a retrospective cohort study using TriNetX, a population-based database that sources data from electronic medical records (EHRs) of 61 health care organizations in the US. Using ICD-10 codes, we created two cohorts of patients with COVID-19: with CRC and without CRC. The primary aim was a composite outcome of hospitalization, emergency department (ED) visits, and mortality. Secondary aims of our study included risk of hospitalization, ED visits, critical care admission, intubation, and mortality, individually. We performed propensity score matching (PSM) of 44 variables to control for confounding. Odds ratio (OR) and 95% confidence interval (CI) were used to report associations for the propensity-matched cohorts. Results: In CRC patients, the composite outcome (ED visits, hospitalization, death) was 51.6% with breakthrough infections, higher than 44.3% in matched patients without CRC (aOR = 1.39; [95%CI: 1.17 - 1.53]). CRC patients had a significantly elevated cumulative event probability within 180 days (log-rank test, p < 0.0001). Though mortality and critical care stay were similar, CRC patients had a higher risk of hospitalization (aOR = 1.3; [95%CI: 1.12 – 1.50]) and intubation (aOR = 1.79; [95%CI: 1.06 – 3.03]). In subgroup analysis, CRC patients had a higher composite outcome after 2 doses (aOR = 1.39; [95%CI: 1.17 - 1.53]) and 3 doses (aOR = 1.56; [95%CI: 1.26 - 1.95]). Those with 3 doses faced a higher risk of critical stay (aOR = 1.74; [95%CI: 1.06 – 2.86]). Younger CRC patients (16-64 years) with breakthrough infections were at higher risk of all-cause ED visits (aOR = 2.61; [95%CI: 1.73 - 3.94]). No significant differences were observed based on sex. Conclusions: Our retrospective study provides real-world evidence that CRC patients are at a higher risk of more severe outcomes after breakthrough COVID-19 infections. This may warrant a reevaluation of current preventive measures and the possible need for frequent booster vaccine doses for this patient population. [Table: see text]