I also have dense breasts, and I have had a primary breast cancer in each breast. It has been a year and a half since my second lumpectomy and radiation. I have an MRI and 6 months after I have a mammogram. This will continue until I reach my 5-year mark. At my last mammogram appointment, they added an ultrasound because I was having some lymphedema swelling in my breast. My first cancer also did not show up on a mammogram and I had read about dense breast issues so I requested an ultrasound which showed the malignancy. I was having a lot of pain and could actually feel a lump.