Presentation (CTI)

OBJECTIVES: Colorectal cancer (CRC) screening using fecal immunochemical testing (FIT) has expanded. While FIT is generally well accepted due to the lack of dietary or medication restrictions, test results may be unstable during the summer because of hemoglobin degradation. However, recent advances in FIT technology have improved its reliability across all seasons. Therefore, we assessed the seasonal variation in FIT performance using large-scale data of community-based screening.
METHODS: A total of 383,793 individuals participated in community-based screening in Ibaraki Prefecture from April 2021 to March 2023. Participants whose eligibility was confirmed on the testing day were included in the analysis. The four seasons were defined according to the criteria of the Japan Meteorological Agency. The positive rate, CRC detection rate, and positive predictive value (PPV) were calculated for each season. The chi-square test was used to compare these indicators in each season.
RESULTS: The subjects were divided by season as follows; 37,087 in spring, 130,824 in summer, 144,247 in autumn, and 58,261 in winter. The average of the performance indicators was 6.7% for the positive rate, 0.23% for the CRC direction rate, and 3.5% for the PPV. The positive rate in spring (7.5%) was higher than in other seasons, while the CRC detection rate in winter (0.25%) was higher than in other seasons. There are no statistically significant differences in test performance indicators between summer and winter; positive rates were 6.8% vs. 6.8%, CRC detection rates were 0.23% vs. 0.25%, and PPVs were 3.3% vs. 3.6%.
CONCLUSIONS: There is no significant difference in the seasonal variations of test performance indicators in FIT screening. Stable results can be obtained across all seasons, and it is unnecessary to use specific seasons. This flexibility makes it convenient for subjects to decide whether to participate in FIT screening at any time.