The Problem With Statistics
Doctors commonly cite a statistic – a mammogram may reduce your risk of dying by 20%. However, a recent study from the Netherlands has demonstrated that this number is likely inaccurate and that more women may be harmed either by the procedure or by false positives leading to unnecessary treatment.
The study was attempting to analyse why fewer women were dying of breast cancer in the Netherlands after an aggressive screening program was established in 1989 which included regular mammogram – the participants of the study included Dutch women who were screened every other year between 1989 to 2012. This meant nearly 8 million women were included in the analysis.
The intention of the study was to determine if regular mammography screening would affect the number of advanced cases of breast cancers detected and therefore, the number of deaths from the disease. Dr. Philippe Autier from the University of Strathclyde Institute of Public Health led the study and this is what he has to say:
“I don’t think the accumulating data show that continuing mammography screening is a good solution, essentially because the price to pay by women in terms of overdiagnosis is enormous.”
The study found that mammograms overdiagnosed 59% of stage 1 cancers and 33% of stage 0 cancers. Since tumours were being identified, women were undergoing treatment they didn’t require – in fact, another study found that an estimated $4 billion is spent per year on treatment due to false positive mammograms.
Previous work published in the Journal of the American Medical Association also concluded that finding additional small cancers without an absence in the overall rate off death suggests widespread over-diagnosis and over-treatment.
Other data even suggests that there is a 50 – 60% chance of receiving a false result after 10 year mammograms.
All this, not to say that no one should do mammograms but that there are significant risks and problems with its overprescription. Next time you’re considering a mammogram screening, get all the facts.