Most breast cancers are detected by the person themself, by detecting a lump or noticing a change in their breast. If you find a lump DO NOT IGNORE IT. Delaying seeing a Doctor by even a few weeks can make a big difference. Would you rather have treatment and be alive OR be scared, put off seeing a Doctor and then be told it's too late???? That may sound blunt/harsh but it's a reality.
Some breast cancers can't be felt and are detected by mammogram only - like mine. I couldn't feel a lump - nothing at all. There were no indications that I had cancer, although in hindsight, I'd been quite tired for a few months and also wasn't feeling quite myself. Could that have been the cancer? I don't know. If it hadn't been for the routine mammogram though, I wouldn't be here to tell the tale.
I know mammograms are not the most pleasant things on earth BUT it's 5 minutes of having your boob squished and that 5 minutes could save your life.
BE SMART - CHECK YOURSELF!