MedicalResearch.com Interview with:
Dr Sian Taylor-Phillips PhD
Assistant Professor of Screening and Test Evaluation
Division of Health Sciences
Warwick Medical School
University of Warwick
MedicalResearch.com: What is the background for this study?
Dr Taylor-Phillips : Psychologists have been investigating a phenomenon of a drop in performance with time on a task called ‘the vigilance decrement’ since World War 2. In those days radar operators searched for enemy aircraft and submarines (appearing as little dots of light on a radar screen). People thought that the ability to spot the dots might go down after too much time spent on the task. Many psychology experiments have found a vigilance decrement, but most of this research has not been in a real world setting.
In this research we wanted to know whether there was a drop in performance with time on a task for breast screening readers looking at breast x-rays for signs of cancer. (Breast x-rays or mammograms show lots of overlapping tissue and cancers can be quite difficult to spot). This was a real-world randomised controlled study in UK clinical practice.
In the UK NHS Breast Screening Programme two readers examine each woman’s breast x-rays separately for signs of cancer. They look at batches of around 35 women’s x-rays. At the moment both readers look at the x-rays in the same order as each another, so if they both experience a drop in performance, it will happen at the same time. We tested a really simple idea of reversing the batch order for one of the readers, so that if they have a low ebb of performance it happens when they are looking at different women’s breast x-rays.
MedicalResearch.com: What are the main findings?
Dr Taylor-Phillips : 1.2 million women’s x-rays were included in the trial.
We found that the intervention had no effect on cancer detection rate, and in fact in an exploratory post-hoc analysis we observed no vigilance decrement at all for expert breast screening readers looking at batches of around 35 women’s breast x-rays.
MedicalResearch.com: What should readers take away from your report?
Dr Taylor-Phillips : We found no reduction in performance or vigilance decrement at all. In fact, we found the opposite of what we were expecting – breast screening readers seemed to get ‘into the zone’ and their performance improved with time on task. They recalled fewer women for further tests as they got nearer the end of the batch while cancer detection rates stayed constant.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr Taylor-Phillips : We are currently analysing how performance changes over longer reading sessions, and whether examining mammograms at different times of day affects performance.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Sian Taylor-Phillips, Matthew G. Wallis, David Jenkinson, Victor Adekanmbi, Helen Parsons, Janet Dunn, Nigel Stallard, Ala Szczepura, Simon Gates, Olive Kearins, Alison Duncan, Sue Hudson, Aileen Clarke.Effect of Using the Same vs Different Order for Second Readings of Screening Mammograms on Rates of Breast Cancer Detection.
JAMA, 2016; 315 (18): 1956 DOI: 10.1001/jama.2016.5257
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