Cancers Detected in Second-Round Fecal Immunochemical Test Screening Still Early Stage

The value of colorectal cancer (CRC) screening lies in CRC prevention through polyp detection and prevention of CRC mortality by early-stage CRC detection. Compared with symptom-driven evaluation alone, all screening modalities lead to cancer detection at earlier stages. This includes cancer detected by fecal immunochemical test (FIT) screening. Most data on FIT screening, however, are derived from the first round of screening. For FIT-based screening to be effective long term, screen-detected cancers must be in an early stage, not only in the first screening but also in later rounds of repeat screening.

In this report from the Dutch national screening database, 15,755 and 3304 cases of CRC were detected at first- and second-round screenings, respectively. The fraction of cases at stage I or II CRC was 66.5% in the first round and 67.7% in the second.

The Dutch use a FIT positivity cutoff of 47 µg hemoglobin per gram of feces. Increasing the cutoff to 250 µg dropped the fraction of cancers that were stage I or II by only 5% in both the first and second rounds, though the overall sensitivity for cancer dropped dramatically with higher cutoffs.