Today there is much hoopla about a new report from the nordic cochrane collaboration. The Press Association tells us that "thousands of women in England could be undergoing unnecessary and potentially devastating treatment for suspected breast cancer".
The Today Programme says that "new research says that breast cancer screening might be doing more harm than good."
The Telegraph that "Screening for breast cancer 'may harm women'"
Because the Cochrane collaboration is one of the most authorative in the world its worth taking it seriously. And yet if you actually read the paper itself its not the big news that everybody is going on about. In fact, the evidence is very similar to much that has been around for at least a decade. There is a chapter in my book which outlines a political scandal around similar figures in 1997.
And even though its not new, the paper itself seems to be much more tentative than the headlines.
Screening likely reduces breast cancer mortality. Based on all trials, the reduction is 20%, but as the effect is lower in the highest quality trials, a more reasonable estimate is a 15% relative risk reduction. Based on the risk level of women in these trials, the absolute risk reduction was 0.05%. Screening also leads to overdiagnosis and overtreatment, with an estimated 30% increase, or an absolute risk increase of 0.5%. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged. In addition, 10 healthy women, who would not have been diagnosed if there had not been screening, will be diagnosed as breast cancer patients and will be treated unnecessarily. It is thus not clear whether screening does more good than harm. Women invited to screening should be fully informed of both benefits and harms.
Its interesting that none of the media outlets link to the paper itself despite it being on public access.
Amidst the panic that goes on around a story like this, the key message that women should be allowed to make a real informed decision always seems to get lost. Surely its down to the patients, not the bureaucrats to make choices like this.
