Exams don't prevent anything. They detect, if you're lucky. The way to prevent is harder and less glamorous: better diet, exercise, maintaining a proportional weight, breastfeeding your babies, limiting the intrusion of synthetic hormones in our bodies. I never hear any of this, common knowledge though it is, in these ads.
We have to take responsibility for ourselves, be more involved in our own health, and stop wearing those damned pink ribbons. What do they say, anyway? That we are against breast cancer? So who is for it?