Experts agree that breast cancer screenings kill women because it zaps them with cancer-causing radiation. But they continue to disagree about whether those deaths are worth it.
The latest round in the cancer screening debate comes from England where Michael Baum, professor emeritus of surgery at University College London, says that, while deaths from breast cancer may be avoided due to screening, any benefit is more than outweighed by deaths due to the long-term adverse effects of screening and unnecessary treatment.
He estimates that, for every 10, 000 women who are screened, three to four breast cancer deaths are avoided at the cost of 2.72 to 9.25 deaths from the long term toxicity of the radiotherapy.
On the other hand, a report on breast cancer-screening, led by Michael Marmot and published in November, concluded that screening should continue because it prevented 43 deaths from breast cancer for every 10,000 women who were screened.
The downside: an estimated 19 percent rate of overdiagnosis. In that survey, 129 of the 681 cancers detected in every 10,000 women would have done them no harm during their lifetime. However, those women undergo unnecessary treatment, including surgery, radiotherapy and chemotherapy.
But despite this higher-than-previous estimate of over-diagnosis, Marmot concluded that the screening should continue.
But while Marmot’s report concluded that screening reduces the risk of dying from breast cancer by 20 percent, Baum disputes these figures, saying the analysis takes no account of changes in treatment that reduce the benefits of screening. Nor does it make use of more recent observational data.
With these data included, estimated rates of over-diagnosis as a result of screening increase to up to 50 percent, he argues.