Telephone Services for Participation Improvement in Colorectal Cancer Screening: a Randomized Health Services Study

This randomized health services study will be performed within national population-based screening program (PCSP) in Poland, including its population, infrastructure and database system.

Individuals aged 55-64 years old, included in PCSP willl be randomly assigned (in 1:1:1 ratio, stratified by gender, age, place of residence) to study arms and invited to screening colonoscopy to local PSCP centers.

Invitation process by post in Control group (1) and partially in Combined group (3) - will be performed by coordinating PCSP center (practice as usual).

Recruitment by telephone conversation in Call Center group (2) and partially in Combined group (3) - will be performed by Screening Up call center company. Colonoscopies will be performed in 6 selected PCSP centers.

The sample size of 2,100 participants per group (350 participants from each group in each center, assuming 5% drop out and access to telephone numbers of 30% participants in relevant arms; calculation is based on a 95% confidence interval +/- 5% error probability) was calculated to detect a difference in participation rate of 15% in control group (based on PCSP participation rate in 2019) vs. 18.7% in Call Center group vs 25% in Combined Invitation group (0.025 significance level with 80% power). The difference was calculated for the Cochran-Mantel-Haenszel test, assuming that the initial reporting in the control group will be as high as it was in 2019.