Thank you for asking that question.
Everything has pluses and minuses. There are a few downsides to screening.
One of them is that about 7% to 10% of women who get a mammogram may get called back to have a second look. About 95% of those women will get a double-check, be able to breathe a sigh of relief and go home knowing they got a little bit of extra care and attention. They're good until their next screen. Most of them will be fine.
I don't like to diminish the worry. I mean, mental health is important as well. I don't diminish it, but in comparison with a delayed diagnosis, I think it's trivial. That's my own personal opinion about that.
I would say there is a more significant harm in the form of something called overdiagnosis, which is essentially the chance that your cancer is found. You poked the bear. You went hunting for cancer and you found one, but that cancer could have sat there until you died of other causes and you would have never had to have the treatment. The treatment itself is unpleasant, to say the least.
However, the good news is that, for the youngest women, that is a very trivial likelihood. It's around 1% or less than 1%. That is because your chance outliving your cancer, basically, is based on whether or not that cancer is aggressive. Is it one that's going to grow? Also, how much lifespan do you have left?
On the one extreme end, if you do a mammogram on somebody who's 85 and she has heart disease, that's overdiagnosis, but for somebody who's 40, it's not going to—