When the overdiagnosis is politicized

Rudy Giuliani, the Republican mayor of New York, on that fateful September 11, at an election meeting said: "I had prostate cancer 5 or 6 years ago and I thank God to be an American citizen because here the probability of survival at five years for this cancer is 82%, while in the UK, due to socialized medicine, this value is only 44%." We must clarify that in the US, PSA screening is widespread while in the UK it’s not so. According to Gerd Gigerenzer (I have extracted this case from his book "Risk Savvy"); Giuliani’s words conceal a big mistake, because in reality, although it seems a contradiction, mortality from prostate cancer in the two countries is practically the same. So how is it possible that the survival rates are so different? To explain it, Gigerenzer describes two biases that encourage the intentional error of the conservative politician:

Could the cancer numbers be better explained?

Cristina Roure explained in a post in her blog series "Pantone", an experience that Gerd Gigerenzer, Director of the Max Planck Institute for Human Development in Berlin, wrote in the book "How to know when numbers deceive you", where more than half of the surveyed gynaecologists did not estimate, after seeing published scientific data, what was the probability to have cancer of an asymptomatic woman’s with a positive screening mammogram. In fact the error of most of the colleagues was monumental: they said it was 90% when in fact it was 10%.

In a recent post, I commented on the book of Peter Ubel "Critical Decisions", in which the author showed what the emotional force of numbers was, both for patients and for the doctors. In this certainly worrying line, I want to give you a shred of hope. There are ways to show the numbers in order to reduce the reigning confusion. Many experts are warning us to flee percentages, the ineffable pies and the relative risks, and we have to get used to talking to patients of real numbers, pictograms with people and absolute risks. To make myself understood, I include a couple of graphics from the Harding Center for Risk Literacy, a centre which is in the orbit of Gigerenzer and Max Planck. The first is a pictogram on the evaluation of prevention programs for prostate cancer based on PSA controls and anal touch of the gland.