Mammography screening: an incremental cost effectiveness analysis of double versus single reading of mammograms.
OBJECTIVE
To compare mammography reading by one radiologist with independent reading by two radiologists.


METHODS
An observational non-randomised trial at St Margaret's Hospital, Epping.


METHODS
33 734 consecutive attenders for breast screening in the main trial and a sample of 132 attenders for assessment who provided data on private costs.


METHODS
Three reporting policies were compared: single reading, consensus double reading, and non-consensus double reading.


METHODS
Numbers of cancers detected, recall rates, screening and assessment costs, and cost effectiveness ratios.


RESULTS
A policy of double reading followed by consensus detected an additional nine cancers per 10 000 women screened (95% confidence interval 5 to 13) compared with single reading. A non-consensus double reading policy detected an additional 10 cancers per 10 000 women screened (95% confidence interval 6 to 14). The difference in numbers of cancers detected between the consensus and non-consensus double reading policies was not significant (95% confidence interval -0.2 to 2.2). The proportion of women recalled for assessment after consensus double reading was significantly lower than after single reading (difference 2.7%; 95% confidence interval 2.4% to 3.0%). The recall rate with the non-consensus policy was significantly higher than with single reading (difference 3.0%; 2.5% to 3.5%). Consensus double reading cost less than single reading (saving 4853 pounds per 10 000 women screened). Non-consensus double reading cost more than single reading (difference 19 259 pounds per 10 000 women screened).


CONCLUSIONS
In the screening unit studied a consensus double reading policy was more effective and less costly than a single reading policy.
Brown
J
J
Health Economics Research Group, Brunel University, Uxbridge, Middlesex.
Bryan
S
S
Warren
R
R
D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000191:economics / Q000517:prevention & control*; D003362:Cost-Benefit Analysis; D004739:England; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008327:Mammography / Q000191:economics* / Q000379:methods* / Q000592:standards; D008403:Mass Screening / Q000191:economics* / Q000379:methods / Q000592:standards; D015588:Observer Variation; D011871:Radiology; D012680:Sensitivity and Specificity