EXPERTS are divided on the impact of false-positive mammogram screening results, with new research showing that women who receive a false-positive result are more likely to attend their next screening appointment.

Irish research published in the Journal of Medical Screening found that re-attendance rates were 90.7% for women who were recalled for a false-positive assessment, compared with 89.0% for women who were not recalled. The results reached statistical significance despite the small proportional difference. (1)

Professor John Boyages, director of the Westmead Breast Cancer Institute, said the research confirmed his “gut feeling” that having a false-positive result actually encouraged women to return.

“From talking to patients, my feeling is that women are grateful that we’ve been so thorough, so they’re more motivated to come back next time,” Professor Boyages said.

However, Associate Professor Liz Wylie, BreastScreen WA medical director, said the Irish results were “completely contrary” to the experience of her screening service.

A recent unpublished audit by BreastScreen WA, involving about 1 million women over 10 years, found a “significant decrease” in return to screening among women who had received a false-positive result, Dr Wylie said.

The Irish research found that the longer women waited between being recalled and receiving the non-malignant diagnosis, the less likely they were to re-attend. The BreastScreen WA research confirmed this finding.

“The longer women sit around thinking they’ve got breast cancer, the more traumatic that experience is and the less likely they are to participate in future,” Dr Wylie said.

She said that false-positive recalls also meant that women with actual breast cancer had to wait longer to access limited diagnostic resources when recalled.

BreastScreen WA was working towards a less “risk averse” approach and reducing its false-positive rate, mainly through providing more staff feedback on the ill effects of false positives. “We recognise that there are adverse consequences of a high recall rate. It’s a waste of resources and we’re working to reduce it,” Dr Wylie said.

The Irish study also found that the more invasive the procedure used in diagnosing a benign tumour, the less likely women were to re-attend. Re-attendance rates were 80% for women who had an open surgical biopsy, compared to 91% for women who had no tissue sampling.

Data from the Australian Institute of Health and Welfare shows that national breast cancer screening participation rates have decreased from a high of 57.1% in 2001/02 to 54.9% in 2007/08. At the same time, recall rates have increased, from a low of 5.8% in 1996 to 9.5% in 2008. (2)

– Sophie McNamara

1. J Med Screen 2011; 18: 30-33

2. Australian Institute of Health and Welfare, BreastScreen Australia monitoring report 2006-2007 and 2007-2008

Posted 9 May 2011

2 thoughts on “False-positive mammograms split experts

  1. MJAInsight editors says:

    Update: New Spanish research on this topic has found that a false-positive result in the first screening reduced the likelihood of re-attendance.

  2. Liz says:

    The Australian research is correct IMO; it happened to me.
    A false-positive that resulted in a call-back and worry for more than 2 weeks, then a full day of repeat mammograms, ultrasound, clinical breast exam and finally several biopsies of my right breast. I was exhausted, badly shaken and very afraid.
    I had another horrible night, awake all night, couldn’t eat, felt physically sick and even vomited… my husband took the day off work and accompanied me to my appointment to get my result from the breast screen surgeon.
    I got the all-clear and was enormously relieved – my husband and I decided to forget work that day and had a nice long lunch and a massage, but the entire experience prompted me to do what I always do with cancer screening – DO MY OWN READING!
    I think a friend’s diagnosis prompted me to just accept the invitation – a huge mistake, as I know women never receive honest and complete information about screening. It was over 25 years ago that I was ordered into cervical screening, refused and took myself off to the medical library and was appalled to get to the truth – that empowered me to refuse pap testing and even when GPs started receiving incentive payments from the government to reach screening targets for pap testing (unethical as these payments are not mentioned to women), I was safe as an informed woman…No, thank you!
    It has surprised and alarmed me that the facts about cervical screening have been very slow to emerge and most women are still completely misled as to the actual benefits and high risks with the testing.
    Anyway, I was right, the breast screening brochure, like the Pap screen brochure, was not about informing women, but basically selling testing, full of puff and spin and critical omissions.
    I took myself off the registry and have moved on… more women are starting to understand that we don’t have to jump when commanded to do so by the govt and doctors – our individual health matters to us, not govt-set targets. I’m not jeopardising my health to satisfy a target.
    Women have a legal right to make informed decisions about screening; targets are offensive and inappropriate, we’re not sheep. Men are not treated in this way – the risks of prostate screening came out very quickly and doctors were warned to get informed consent. No targets, no secret payments to GPs… respectful and ethical conduct for men, disrespectful and unethical for women.
    FACT: An unacceptable and paternalistic double standard exists in women’s cancer screening.
    Forget targets and be careful of your doctor’s recommendations – are they getting a secret kickback? (Financial incentives legislation and PIP scheme) Ask your doctor lots of questions, take control of your healthcare & protect your body. Professor Michael Baum, UK breast cancer surgeon is my hero – brave enough to speak out about the risks of breast screening. How dare he tell women the truth and treat them like adults? His latest lecture at UCL, “Breast cancer screening: the inconvenient truths” is at the Medphyzz site – please listen to it! It may spare you a lot of grief – over-diagnosis is a serious and hidden issue in breast screening. (as well as false positives)
    The Nordic Cochrane Institute have also produced, “The risks and benefits of mammograms” – at their website – they were so concerned at the state of the screening brochures – misleading and incomplete.
    Why is it acceptable to treat women in this way? Are we third class citizens?

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