Digital screening for breast cancer

Digital mammography can detect breast cancer earlier than conventional breast x-rays, reported three newspapers on 16 June 2005. The reports were based on a press release updating the findings from a large randomised controlled trial. It is not possible to evaluate the new results as full details are not available.

• Research indicates that digital mammograms could detect an extra 1,500 breast cancers for every 500,000 women screened, reported three newspapers (1-3). Two reported the actual research findings, that digital mammography detected one more cancer for every 333 women screened (1-2). All mentioned that the digital imaging technique is also being tested for the NHS.

• The reports are based on a company press briefing and press release (4) updating results from a randomised controlled trial (5). In the trial 25,263 women were randomised to receive a conventional film or a digital mammogram, and the cancer detection rates between the two groups were compared. The results presented in the press release show that digital screening detected more breast cancers than analogue methods, and this detection rate approached a significant level for the women aged 50-69 in the trial. It is not possible to assess the validity of these results as full details are not available.

• The newspaper reports accurately summarise the information and use quotations provided in the company press release. Only one of the reports referred to the age of the women to who the results applied (1). The Sun (3) incorrectly stated that the trial involved half a million women.

Systematic reviews

Information staff at CRD searched for systematic reviews relevant to this topic. Systematic reviews are valuable sources of evidence as they locate, appraise and synthesize all available evidence on a particular topic.

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