Peter Gotzsche, director of the independent Nordic Cochrane Collaboration in Copenhagen, Denmark, said he spent more than 10 years analyzing breast screening studies and found regular mammograms saved one life for every 2,000 women, but harmed 10 other women.
The women harmed include those who were diagnosed with cancerous cells that would have disappeared naturally or remained benign, Gotzsche said.
"I believe the time has come to realize that breast cancer screening programs can no longer be justified," he told The Guardian. "I recommend women to do nothing apart from attending a doctor if they notice anything themselves."
Gotzsche and colleagues found 1-in-3 cancers detected by screening was misdiagnosed, and while breast cancer deaths have gone down, better treatment and better-aware women, who go to the doctor as soon as they find a lump, are responsible. Half of all breast cancers are found between screenings, he added.
The findings are published in Gotzsche's book, "Mammography Screening: Truth, Lies and Controversy."