We've just closed out a month where everything from the White House to professional football players' cleats turned pink to raise awareness of breast cancer. Every year during October, there's a constant focus on raising money for breast cancer research, and on reminding women to get screened. The mantra is always, "Early detection saves lives."
As we've written before, it's an article of faith for many patient advocates and medical organizations that cancer screening is an unadulterated good. But a new study in the Lancet on breast cancer screening provides yet more evidence that while mammography can save lives, screening also causes serious harms. They find that for every woman whose life is saved, three other women will be overdiagnosed and face unnecessary treatment. That doesn't even count the harm caused by false positives on screening mammograms, which lead to unnecessary stress as well as biopsies and other tests. It's worth noting that the population in the Lancet study includes women over 50, in line with the US Preventive Services Task Force's recommendations. Expanding screening to women under 50 means that fewer of the women screened will have harmful cancers, so the harm of overdiagnosis is more likely to outweigh benefits from catching cancer early.
To go along with the Lancet study, the New England Journal of Medicine has a new Perspective piece by Drs. Steve Woloshin, Lisa Schwartz, William Black, and Barnett Kramer. They make a forceful argument against one-sided pro-screening campaigns that present the benefits of screening, while ignoring the harms. The piece is linked to a great slide show with some of the most egregious pro-screening advertizements.