Over-diagnosis from cancer screening

Barry Kramer (from The National Cancer Institute) on lead-time bias (using an image of Snidely Whiplash tying someone to train tracks): ‘Ineffective screening is like a pair of binoculars for the person tied to the tracks: you can see the train coming at you sooner, but it doesn’t change the moment of impact. Survival rates after a screening diagnosis increase, even when no one lived a day longer: people have cancer for longer when the diagnosis comes long before any symptoms. Screening is effective, on the other hand, when earlier detection means more people do well than would have done if they’d gone to the doctor first when there were symptoms.’                                     Yet people who do not understand lead time bias (yes, even doctors!)  mis-read research findings and spread misinformation that screening mammography is effective ie that women whose breast cancer is found by screening mammography live longer than those with symptomatic breast cancer.


About bmitzi

Medical writer, author, artist. Cancer campaigner. Aiming always to improve health services and bring compassion into health care.
Aside | This entry was posted in Breast Cancer, Campaigns, Compassion in healthcare, Screening, Screening Mammography and tagged , , , , , , . Bookmark the permalink.

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