The answer is clearly explained in yet another article which discusses the harms and ineffectiveness of screening mammography. There is an easy to understand analysis which shows what happens if 10,000 women have annual mammograms starting at age 50: how many women would be harmed, how many would have their lives saved – and other detail.
‘The harder you look, the more cancers you’ll find, but most will be harmless and never threaten anyone’s life.’
‘What if everything your doctor told you about breast cancer was wrong?’ Christine Aschwanden. Motherjones.com, 6 October 2015.