This is the first evaluation study to assess the demographic characteristics of the colorectal cancer (CRC) cases detected in the prevalent round of the population-based Colorectal Cancer Screening Programme (CRCSP) in Hong Kong and to explore the effectiveness of the programme on the stage distribution of CRC.
This study covered the period between 28 September 2016 and 31 December 2018. Information on CRC diagnosis, age and stage at diagnosis were retrieved and reviewed by the Hong Kong Cancer Registry (HKCaR). The CRC detection rate among CRCSP-screened participants and incidence rate among the Hong Kong general population were calculated respectively. The odds ratio (OR) was calculated to measure the strength of association and quantify the effect of CRCSP on stage shift between CRCSP-detected CRC cases and an age-matched cohort of CRC cases diagnosed outside the programme.
The CRC detection rate among participants of the CRCSP during the study period was 736.0/100,000, whereas the overall CRC incidence rate among general population of similar age groups was 393.7/100,000. For all ages and both sexes, the OR of stage I CRCSP-detected CRC compared to the CRC from the age-matched cohort was 3.91 (95%CI=3.41–4.48) and the OR dropped to 0.54 (95%CI=0.41–0.70) at stage IV. Meanwhile, the overall OR of CRCSP-detected CRC compared to CRC from the age-matched cohort dropped from 2.24 (95%CI=1.97–2.56) to 1.62 (95%CI=1.40–1.87) with increasing age.
The present study has demonstrated the initial impact of the CRCSP on shifting the stage at diagnosis towards earlier stage. The benefit of stage-shift was similar for all ages from 60 to 77 in both sexes and seems to increase with younger age. Given the stage-dependent survival outcomes, this stage-shift could lead to a reduction in CRC-associated mortality in Hong Kong in future.
- • Analysis of the first round of the population-based Colorectal Cancer Screening Programme (CRCSP) in Hong Kong.
- • Significant shift towards earlier stage was observed in the CRCSP-detected group in keeping with other studies.
- • Early cancer (stages 0-II) was found in 65% of those with colorectal cancer in the CRCSP-detected group.
- • Benefit of stage-shift was similar in both sexes and seems to increase with younger age.
Colorectal cancer (CRC) is a major public health problem. The Global Burden of Disease Study showed that the incidence of CRC increased greatly from 0.83 million in 1990 to 1.83 million in 2017 . According to the Hong Kong Cancer Registry (HKCaR), CRC was the commonest cancer and the second ‘cancer killer’ in Hong Kong in 2018 . The number of CRC new cases increased from 2,022 in 1990 to 5,634 in 2018, accounting for 16.6% of all new cancer cases diagnosed in 2018. Meanwhile, the number of deaths attributed to CRC also increased from 889 in 1990 to 2,314 in 2018, accounting for 15.9% of all cancer deaths in 2018. The age-standardised incidence rate (per 100,000 persons) increased from 30.6 in 1990 to 35.0 in 2018; whereas, the age-standardised mortality rate (per 100,000 persons) decreased from 13.3 in 1990 to 12.2 in 2018 .
Population-based CRC screening programmes have been introduced in many countries . CRC screening aims to mitigate the risk of CRC mortality through detection of cancer at earlier stages, and to reduce the incidence and mortality of CRC through detection and removal of precancerous lesions.
The stage of CRC at diagnosis has a major impact on 5-year survival rates. Overall survival is more favourable in patients detected by screening colonoscopy when compared to patients detected after the appearance of clinical symptoms . Studies evaluating the CRC screening programmes in Western populations have consistently shown the phenomenon of stage shift towards earlier stage in CRC cases detected by screening as compared with those without screening . Moreover, studies have demonstrated that screening programmes could lead to reductions in incidence and mortality of CRC .
In Hong Kong, the Cancer Expert Working Group on Cancer Prevention and Screening has made recommendations on colorectal cancer screening . A government-subsidised, population-based Colorectal Cancer Screening Programme (CRCSP) has been launched by the Department of Health (DH) since September 2016. Participants will first receive Faecal Immunochemical Test (FIT) tube. FIT-positive participants will then receive colonoscopy examination service. FIT-negative participants will receive FIT again every two years until they fall outside the screening age of 75 .
The present study aimed to assess the demographic characteristics of the CRC cases detected in the prevalent round of the CRCSP in Hong Kong and to evaluate the impact of the programme on the stage distribution of CRC.