My understanding is that other than mammogram & ultrasound on remaining breast/ breast tissue is the only regular testing. Medico's say that the evidence shows no benefit in other tests or imaging. Tumour markers are not reliable in breast cancer, until known to be metastatic, and even then best taken as pert of an overall picture with symptoms and scans.
The advice will generally be to see one of your team with any new symptoms/pain that last more than a couple of weeks and not releived by available medications (panadol & anti inflammatories)
The research suggests no survival benefit in regular scans as opposed to scans done in response to a new symptom