Effectiveness of population-based colorectal cancer screening programme in down-staging

Area of Science:

• Public Health
• Oncology
• Screening Programs

Background:

• First evaluation of demographic characteristics for colorectal cancer (CRC) cases in Hong Kong's population-based Colorectal Cancer Screening Programme (CRCSP).
• Assesses the CRCSP's effectiveness on the stage distribution of CRC diagnoses.

Purpose of the Study:

• To evaluate the demographic profile of CRC cases identified by the CRCSP.
• To determine the impact of the CRCSP on the stage at diagnosis for colorectal cancer.

Main Methods:

• Retrieved and reviewed CRC diagnosis, age, and stage data from the Hong Kong Cancer Registry (HKCaR) for cases diagnosed between September 2016 and December 2018.
• Calculated CRC detection and incidence rates. Used odds ratios (OR) to compare stage distribution between CRCSP-detected cases and an age-matched cohort diagnosed outside the program.

Main Results:

• CRC detection rate in CRCSP participants was 736.0/100,000, higher than the general population incidence rate of 393.7/100,000.
• OR for Stage I CRCSP-detected CRC was 3.91, while Stage IV OR was 0.54, indicating a shift towards earlier stages.
• The overall OR for CRCSP-detected CRC decreased from 2.24 to 1.62 with increasing age, suggesting benefits across age groups.

Conclusions:

• The CRCSP has demonstrated an initial positive impact by shifting CRC diagnoses to earlier stages.
• This stage-shift benefit was consistent across ages 60-77 and appeared more pronounced in younger individuals.
• The observed stage-shift is anticipated to decrease CRC-associated mortality in Hong Kong.