Effect of subject age on costs of screening for colorectal cancer.

STUDY OBJECTIVE

The aim was to estimate costs and yields of faecal occult blood screening and rescreening for colorectal cancer, for differing age cohorts.

DESIGN

Cost and clinical data were used as the basis for modelling the expected costs, and cost savings, resulting from the treatment of screen detected cancers, as compared with cancers detected by symptomatic presentation.

SETTING

Data were derived from the MRC screening trial currently in progress in Nottingham.

PARTICIPANTS

Approximately 140,000 subjects, age 50-79 years, were randomly allocated to a test (screened) and a control (unscreened) group.

MAIN RESULTS

The net costs of detecting and treating a cancer following colorectal screening fall as the age of the target population increases, owing principally to the increasing incidence of the disease with age. Generally, the marginal detection and treatment costs falls for all age groups with the first screening round, but rises considerably with the second. If allowance is made for cancers prevented as a result of early detection and excision of adenomas, the costs of screening are substantially reduced for all age groups.

CONCLUSIONS

Assuming a cost per QALY (quality adjusted life year gained) equivalent to that derived for the breast cancer screening programme, and a QALY gain from colorectal screening of one year, three screens, each separated by two years, appear economically justified for populations aged 60 years and above. Expected gains from cancer prevention make two screens justifiable for those between 45 and 59 years of age.