# Influence of Comorbidities on Colorectal Cancer Screening Participation and Mortality

## TL;DR

This study shows that patients with certain health issues are less likely to get colorectal cancer screening and face higher mortality, suggesting outreach programs should consider these factors.

## Contribution

The study identifies how comorbidities affect screening participation and mortality, proposing improved outreach by incorporating patient-level data.

## Key findings

- Patients with abnormal lab results were less likely to receive or complete colorectal cancer screening.
- These patients also experienced significantly higher mortality over 8 years.
- Incorporating patient-level factors into outreach could improve screening rates and outcomes.

## Abstract

•Centrally organized screening outreach programs increase colorectal cancer (CRC) screening participation, but outreach services can be improved.•An agnostic screening invitation, in which every patient is invited to screen, may not be consistent with the intent of primary care providers.•This study showed that patients meeting abnormal lab thresholds were much less likely to receive an order for colorectal cancer screening, less likely to complete screening, and experienced higher mortality.•Health systems can enhance the delivery of an organized screening program by incorporating patient-level factors to guide outreach services.•Greater trust in organized screening programs would increase adoption, which could in turn improve overall screening rates.

Centrally organized screening outreach programs increase colorectal cancer (CRC) screening participation, but outreach services can be improved.

An agnostic screening invitation, in which every patient is invited to screen, may not be consistent with the intent of primary care providers.

This study showed that patients meeting abnormal lab thresholds were much less likely to receive an order for colorectal cancer screening, less likely to complete screening, and experienced higher mortality.

Health systems can enhance the delivery of an organized screening program by incorporating patient-level factors to guide outreach services.

Greater trust in organized screening programs would increase adoption, which could in turn improve overall screening rates.

Organized screening programs improve colorectal cancer (CRC) screening participation, but outreach services can be improved. We sought to understand screening deferral by examining patient-level factors and how they relate to fecal immunochemical test (FIT) orders, completion rates, and long-term mortality.

Patients aged 50-75 years who were not up to date with CRC screening receiving usual care were followed over time (NCT02613260). Patient-level laboratory and cancer registry data were used to identify patients who met a specified laboratory threshold: albumin < 3 g/dL, HIV viral load > 10,000 copies or CD4 < 200 cells/µL, creatinine > 4 mg/dL, platelets < 100,000/µL, total bilirubin > 4 µmol/L, NH3 > 20, positive urine amphetamine or cocaine, serum ethanol > 80, hemoglobin A1C > 10%, and stage 3 or 4 cancer. The proportion of patients with a FIT order, FIT completion in 1-year, and mortality at 8-years were compared in patents with and without the lab abnormality.

Nine thousand six hundred seventy-six patients were eligible for screening, of which 1053 met the criteria for laboratory abnormalities. Patients with laboratory abnormalities were less likely to have a FIT order placed (39.5% vs 66.8%, P < .001) and were less likely to complete FIT screening (21.5% vs 51.6%, P < .001). Moreover, patients with laboratory abnormalities experienced higher mortality at 8-year follow-up (32.6% vs 6.7%, P < .001).

Patients with laboratory abnormalities were less likely to have a FIT order placed and completed, and experienced higher mortality, suggesting that screening was deferred by providers. Future studies should gather provider input to understand how patient-level electronic data could be considered in the implementation of screening services.