Reappraisal of the options for colorectal cancer screening in England.

AIM: The aim was to use newly available data to estimate the cost effectiveness and endoscopy requirements of screening options for colorectal cancer (CRC) to inform screening policy in England.
METHODS: A state transition model simulated the life experience of a cohort of individuals in the general population of England with normal colon/rectal epithelium through to the development of adenomas and CRC and subsequent death. CRC natural history model parameters and screening test characteristics were estimated simultaneously by a process of model calibration. This process was fitted to observed data on CRC incidence in the absence of screening, data from existing screening programmes, and data from the UK flexible sigmoidoscopy (FS) screening trial. The costs, effects and resource impact were evaluated for a range of screening options involving the guaiac or immunochemical faecal occult blood test (gFOBT/iFOBT) and FS.
RESULTS: The model suggests that screening strategies involving FS or iFOBT may produce additional benefits compared with the current policy of biennial gFOBT for 60-74-year-olds. The age at which a single FS screen results in the greatest quality-adjusted life year gain was 55, with similar gains for ages between 52 and 58. Strategies which combined FS and iFOBT showed further benefits and improved economic outcomes.
CONCLUSIONS: Strategies which combine different screening modalities may provide greater clinical and economic benefits. The collection of comprehensive screening data using a uniform format will enable comparative analysis across screening programmes in different countries, will improve our understanding of the disease and will allow identification of optimal screening modalities.