My mother in-law was diagnosed approx 8 years ago. She underwent a lumpectomy and radiation. She has had annual checkups every year since then. Last year she was rediagnosed again on the other side. This time she elected to do a bilateral mastectomy. Good thing she did because not only was it the spot they detected, but after the pathology was done, they found a second smaller lump and the original site was cancerous again.
My mother was also diagnosed 2 years ago. Again she went for annual checkups prior to this. It was a 5mm lump which ended up being stage 1. My wife 2 months later at the age of 32 was diagnosed with DCIS. She underwent a lumpectomy, but because of poor margins around the site, the oncologist wasn't confident of it not returning, so a bilateral mastectomy was done. At her young age doctors were not concerned about her getting regular checkups. In fact the last one prior to her diagnoses, they told her not to return till she was 40. If that would of been the case I may not have a wife anymore.