I'm assuming you're being treated by the NHS in UK? Generally-speaking scans are not repeated. I was diagnosed in 2009 (large multi-focal IDC mass with node involvement), mastectomy, ANC, chemo, rads and onoing endocrine therapy. After 'active' treatment I and had 3 monthly outpatient check-ups and then 6 monthly and will now have annual check-ups going forward. At my local hospital it's usual to have annual mammograms up to 5 years post-diagnosis.
Protocols do vary according to locality and individual cases but, at the end of the day, CT and bone scans are expensive so not normally repeated unless a patient shows symptoms which indicate scan(s) would be appropriate.
I know no one wants to think about the cancer coming back and I am sorry to bring it up but it worries me. How will I know if it comes back or has spread to another part of my body. My cancer had spread to my lymph nodes under my arm and I had them removed along with the primary tumour but what if it has spread through my lymphatic system to other parts how would I or the drs know. Do we get regular scans when we have our 6 monthly follow ups?