Charity campaign ‘overstates benefits of mammography’
The world’s largest breast cancer charity has come under fire for allegedly exaggerating the benefits of mammography screening.
Susan G. Komen for the Cure, the US charity known for its pink ribbon symbol, encouraged women to go for screenings during a breast cancer awareness month campaign last year.
But Professors Lisa Schwartz and Steven Woloshin of the Center for Medicine and the Media at the Dartmouth Institute for Health Policy and Clinical Practice claim the campaign used “hopelessly biased” statistics and ignored the harms associated with mammography.
In an article published on bmj.com, they said the campaign “overstates the benefit of mammography and ignores harms altogether”.
The authors of the report say there is a growing and increasingly accepted body of evidence which shows that although screening may reduce a woman’s chance of dying from breast cancer by a small amount, it also causes major harms.
They say that rather than giving women the impression that screening is a ‘close call’, the charity’s advertising campaign instead used statistics showing that the five-year survival rate for breast cancer when caught early is 98%, compared to 23% when it is not.
The authors claim that comparing survival between screened and unscreened women is biased.
They say if a group of 100 women received diagnoses of breast cancer because they felt a breast lump at age 67 and all died at age 70, the five-year survival rate for the group would be 0%. But if the women were screened and given their diagnosis three years earlier, at age 64, yet still died at age 70, the five-year survival rate would now be 100%, even though no one lived any longer.
They write in the report: “If there were an Oscar for misleading statistics, using survival statistics to judge the benefit of screening would win a lifetime achievement award hands down.”
The authors say that for every life saved by mammography, two to ten women are overdiagnosed, and that women need to be given all the facts about screening rather than marketing slogans alone.
Chandini Portteus, vice-president of research, evaluation and scientific programs at Susan G. Komen for the Cure, said while it is agreed that mammography “isn’t perfect”, it is currently the best widely available detection tool, and that to discourage women from having screenings is "irresponsible".
She said: “We’ve said for years that science has to do better, which is why Komen is putting millions of dollars into research to detect breast cancer before symptoms start, through biomarkers, for example.”
She added: “While we invest in getting those answers, we think it’s simply irresponsible to effectively discourage women from taking steps to know what’s going on with their health.”