Optimal mammography reading volumes: evidence from real life
© Cornford et al; licensee BioMed Central Ltd. 2009
Published: 26 October 2009
The aim of the study was to assess real life reader performance as a function of volume of mammograms read in a large multicentre cohort.
Thirty-seven film readers within the East Midlands Screening Programme had 3 years of consecutive screen reading results available for comparison.
Markers of screen reading performance (overall and first reader cancer detection rates, recall rates, positive predictive value of recall and missed cancers) were compared with volume of films read. Readers were categorised into four groups, according to film reading volume over the 3-year period: <15,000 (that is, on average less than the recommended 5,000/year); 15,000 to <20,000; 20,000 to <25,000; and ≥ 25,000. Statistical analysis was undertaken using SPSS for Windows version 13.
The recall rate in low volume readers (<5,000/year) was 6.9% and was significantly higher than in the other groups combined (4.8%; P ≤ 0.001). These readers also had a lower positive predictive value than higher volume readers (11.7% versus 15.7%, P ≤ 0.001). The cancer detection rate at first read was significantly lower in the higher volume readers (≥25,000) in comparison to the other groups combined (6.6 per 1,000 versus 8.2 per 1000, P ≤ 0.001).
These data support the recommendation that readers should read a minimum of 5,000 mammograms/year. They also suggest that there is an upper limit above which reader performance deteriorates (in terms of cancer detection). With the imminent programme expansion this has implications for service quality. Consideration should be given to the introduction of an upper limit of mammographic reads.
This article is published under license to BioMed Central Ltd.