A team from the Nordic Cochrane Center has an article in this week's BMJ that begins:
Three years ago, we published a survey of the information given to women invited for breast screening with mammography in six countries with publicly funded screening programmes. The major harm of screening, which is overdiagnosis and subsequent overtreatment of healthy women, was not mentioned in any of 31 invitations. Ten invitations argued that screening either leads to less invasive surgery or simpler treatment, although it actually results in 30% more surgery, 20% more mastectomies, and more use of radiotherapy because of overdiagnosis.Pain caused by the procedure was mentioned in 15 invitations, although it is probably the least serious harm, as it is transient.
Since then, little has changed.
The researchers say most info predominantly discusses benefits with no discussion of harms. And they remind readers:
• If 2000 women are screened regularly for 10 years, one will benefit from the screening, as she will avoid dying from breast cancer.
• At the same time, 10 healthy women will, as a consequence, become cancer patients and will be treated unnecessarily. These women will have either a part of their breast or the whole breast removed, and they will often receive radiotherapy and sometimes chemotherapy.
• Furthermore, about 200 healthy women will experience a false alarm. The psychological strain until one knows whether it was cancer, and even afterwards, can be severe.
They conclude: "The one sided propaganda about breast screening is a global phenomenon that has resulted in misconceptions about its effects."