Breast screening is back in the headlines
Breast screening is back in the news.
At the request of the Government and Cancer Research UK, an independent expert panel has scrutinised all the available evidence on the pros and cons of mammography. And this morning they’ve published their findings in The Lancet, putting these into context for the first time.
The panel’s findings are more complicated than you might think, so we’ve produced a detailed Q&A setting out the findings and what they mean, as well as an infographic and a video.
A key finding is that breast screening has significant downsides, as well as undoubted benefits: in addition to the 1,300 lives saved each year, the panel acknowledged that around 4,000 women are ‘overdiagnosed’ by the programme.
Overdiagnosis is a complicated concept – these are genuine cancers spotted by the screening programme (and which wouldn’t have been detected otherwise), which would have grown so slowly they would never caused problems during a woman’s life.
And since there’s absolutely no way to tell the difference between these slow-growing cancers and those that are life-threatening, virtually all women diagnosed through screening are treated – usually with surgery, and potentially with hormone treatment, radiotherapy and – occasionally – chemotherapy.
The concept of ‘harmless’ cancers is likely to be new to many. And the fact that one in five cancers diagnosed by the screening programme wouldn’t have caused harm if left alone is certainly likely to cause concern.
Watch a video about the breast screening review (click to open a new window)
As well as overdiagnosis, screening has other downsides. About four out of five women called back for more tests, turn out not to have cancer. These false alarms cause anxiety, while some women need a biopsy to rule out cancer, and this can be painful.
And the X-rays used to carry out breast screening are linked to a very small number of cancers every year.
But on balance, because of the fact that it saves so many lives, we think breast screening should continue, and we recommend that women to go for screening when invited.
So, now that we better understand the harms breast screening can cause, what are researchers doing to minimise them?
Three key questions, if properly answered, could make a big difference: firstly, who to screen, secondly, what to screen them with, and finally, what to do with cancers when they’re found.
Thankfully the answers to these crucial questions are already being sketched out in labs and hospitals around the world. So let’s tentatively peer into the future and see what breast screening may look like in a decade’s time.