The impact of CT colonography for colorectal cancer screening on the UK NHS: costs, healthcare resources and health outcomes.

BACKGROUND

Biennial faecal occult blood testing (FOBT) for individuals aged 60-69 years is the primary screening tool for colorectal cancer (CRC) in the UK NHS, despite a large number of patients undergoing an unnecessary optical colonoscopy (OC) and evidence from modelling studies to suggest that more cost-effective technologies exist. CT colonography (CTC) is an emerging CRC screening technology with the potential to prevent CRC by detecting pre-cancerous polyps and to detect cancer at an earlier stage.

OBJECTIVE

to assess the impact of introducing CTC into the UK NHS screening programme for CRC on key health outcomes as well as the NHS budget and healthcare resource capacity.

METHODS

a discrete Markov model was used to reflect the natural history of CRC and the impact of three screening scenarios (biennial FOBT with and without CTC triage of patients referred to OC, and CTC every 5 years) on a range of health outcomes, including the incidence and prevalence of CRC, in a hypothetical cohort of individuals. The yearly costs, health outcomes and healthcare resource capacity requirements were estimated over a 10-year period (2009-18).

RESULTS

using CTC to follow up FOBT-positive patients (scenario 2) was less costly than directing all FOBT-positive patients to OC (scenario 1); saving £776 283 over 10 years for 100 000 individuals invited for screening (year 2007 values), primarily by avoiding approximately 1700 OCs, but was estimated to require 2200 additional CT scans. Implementing a programme of 5-yearly CTC as a primary screen is expected to be more expensive than FOBT screening over the short term (driven by high screening and diagnosis costs), despite substantial savings in treatment costs for CRC over the 10-year time horizon of the model and improved health outcomes.

CONCLUSIONS

adding CTC into the existing NHS Bowel Cancer Screening Programme as part of a preventive screening strategy could be less costly to the NHS over the longer term when used to triage FOBT-positive patients to appropriate follow-up. Increased demand for radiology services may be compensated for by reduced demand in endoscopy units.