I Had Breast Cancer 1year Ago Stage 2 I Had

I had breast cancer 1year ago stage 2 I had a lumpectomy and radiation with clean margins and no lymph node involvement I am on tamoxifen I also have fibroidadenoma I had a good mammogram and us this year but my mri showed a 6mm nodule in the other breast I am scheduled for a mri breast biospy and I am very nervous what are the chances this is cAncer or fibroid