My girlfriend has just been diagnosed with grade 3 breast cancer if she goes into remission what do we do?

Continued followup. : If you really mean grade 3 breast cancer that is usually referring to pathologic type, but has much less significance than stage 3 breast cancer, which is a more advanced breast cancer, usually with significant size and invasion and/or spread to lymph nodes. In any case, if she goes into remission by being treated she needs continued followup for which this depends on the stage and treatment.