Cost-effectiveness of population-based screening for colorectal cancer in Hong Kong Chinese

Background: Many Asian countries, including Hong Kong, have experienced an increase of two to four times in colorectal cancer (CRC) incidence during the past few decades. CRC has recently become the second leading cause of cancer-related mortality in Hong Kong after lung cancer. There has not been a systematic assessment of the cost-effectiveness of CRC screening in Asia. Objective: To assess the cost-effectiveness of alternative CRC screening strategies (i.e. FOBT, sigmoidoscopy, colonoscopy or combinations thereof at different intervals) in average-risk Hong Kong Chinese. Methods: We specify a state-transition Markov model which is modified from a previous US model that simulates the natural history of the adenoma-carcinoma sequence as a function of age, sex and other risk factors. The model also contains a screening component that allows for the detection and removal of adenomas and possibly an early diagnosis of CRC; and a treatment component for all persons diagnosed with CRC. This modified model reflects the clinical practice in Hong Kong. Data are from local hospitals and laboratories, clinical trials, prospective studies and other published literature. The stopping age (69 vs. 79 years) for the different CRC screening strategies are also explored. Main outcome measures are cancer incidence reduction, years of life saved (YLS), lifetime costs, and incremental cost-effectiveness ratios. Sensitivity analyses are performed to assess the stability of the results within the plausible ranges of uncertain parameters and to establish a set of epidemiologic threshold parameters for which the different types of CRC screening should be considered. Anticipated significance of findings: Results from the mathematical model which simulates clinical practice can use to inform clinical guidelines in Hong Kong. A set of epidemiologic threshold parameters for which the different types of CRC screening should be considered is also useful especially given the continuing upward trend of CRC incidence among many Asian countries.