Effect of low-dose acetylsalicylic acid on early detection of advanced colorectal neoplasms

Interventions: Group 1: Acetylsalicylic acid (ATC-Code B01AC06), 100mg/day, peroral application, for 4 days.
Stool sampling one day before the start of drug intake (baseline, reference sample) and on the 3rd, 4th, and 5th day after start of drug intake (samples after the intervention after different cumulative doses).
Primary outcome(s): Effect of three days of repeat intake of 100 mg acetylsalicylic acid (cumulative dose of 3 x 100 mg) on sensitivity for early detection of advanced colorectal neoplasm (defined as colorectal cancer, advanced adenoma or sessile serrated polyp/adenoma in size = 1 cm), measured via a fecal immunochemical test (OC-Sensor) at the predefined cutoff level of 10.0 µg hemoglobin/g feces.
Study Design: Allocation: N/A: single arm study; Masking: Open (masking not used); Control: uncontrolled; Assignment: single; Study design purpose: screening