Since 1991, breast cancer deaths have decreased by around 25 percent. Many in the field have credited mammograms and early detection with contributing to this reduction, but a new study suggests that mammograms are actually "overdiagnosing" breast cancer and leading to months of unnecessary treatment for women for cancers that would have never caused harm.
The study, which was published in the Medical Journal of Australia
, was conducted by breast cancer researchers Robin Bell and Robert Burton. The two scientists found that for every 2,000 women who underwent breast cancer screening via Australia's publicly funded BreastScreen program over a 10-year period, one would have her life prolonged but 10 healthy women would be diagnosed as breast cancer patients and treated unnecessarily. They argued that a sizable percentage of certain cancers are overdiagnosed.
The problem as it stands is that doctors cannot always foresee the course of each individual tumor. So the current protocol has followed a "treat it just in case" path which may save a life — but more often than not leads to unnecessary treatment.
As you can imagine, the new Australian study has produced a firestorm of opposition within the health care community. Australia's public health adviser David Roder and Cancer Council Australia CEO Ian Olver wrote an "opposing view" editorial in the same issue of the Medical Journal of Australia
, arguing that the reduction in breast cancer mortality in Australia reflects both treatment and screening effects.
From their editorial:
"There is no consensus on levels of overdiagnosis, with estimates worldwide varying from close to zero to over 30% of diagnosed cancers, irrespective of whether in-situ lesions were included. The estimates vary so widely that interpretation is difficult. Research is needed to better define levels of overdiagnosis and, ideally, to develop more effective means of determining at diagnosis the potential for screen-detected and other breast cancers to progress."