THE ASSOCIATION BETWEEN ORGANISED COLORECTAL CANCER SCREENING AND REDUCTION OF ITS RELATED MORTALITY: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background To evaluate the long-term association between organised colorectal cancer (CRC) screening and reduction of CRC-related mortality. Methods We systematically reviewed studies on organized CRC screening through PubMed, Ovid Medline, Embase and Cochrane database from its inception to November 2020. Moreover, we retrieved the matched CRC-related mortality (over 50 years) of those areas from the initial year of CRC screening programmes to the latest data available obtained from the International Agency for Research on Cancer (IARC). The mortality in the initial year and the latest year was used to calculate the age-standardised mortality ratio (ASMR). We adopted a random-effects model to synthesis the ASMR. Subgroup analyses were performed according to the screening period and modalities. Furthermore, a linear mixed model (LMM) was conducted as a sensitivity analysis. Results CRC screening programmes have been conducted in 58 countries/regions. After matching with the IARC database, we recorded >2.5 million CRC-related deaths from 22 countries where rollout screening programmes were performed. The screening modality with a provision of choice between faecal tests and colonoscopy as the primary screening test was associated with a 38.1% reduction in CRC mortality (ASMR=0.619, 95%CI: 0.549-0.698), which was higher than programmes that offered guaiac faecal occult blood test (gFOBT) (0.894, 0.835-0.958), faecal immunochemical tests (FIT) (0.879, 0.847-0.913), gFOBT or FIT (0.882, 0.835-0.932), and faecal tests or flexible sigmoidoscopy (0.840, 0.786-0.898). The longer duration of screening was associated with a higher reduction in the pooled ASMR. In particular, the pooled ASMR became non-significant (0.987, 0.934-1.043) when the FIT screening was implemented for less than 5 years (IDDF2021-ABS-0179 Figure 1. The pooled age-standardised colorectal cancer-related mortality ratio by screening modalities and screening duration). The LMM result also showed a 0.172 decrease in ASMR (P Conclusions A CRC screening programme running for >5 years was associated with a reduction of CRC-related mortality. Countries with a heavy burden of CRC should implement sustainable, organised CRC screening providing a choice between faecal tests and colonoscopy as a preferred primary screening test.