Hello Dr., I just came back from having my mammogram and breast ultrasound. The Radiologist found shadowing o both breasts, on the ultrasound. I do have a past history of breast cancer, Stage 0, DCIS, and was put on Tamoxifen for five years after a breast biopsy and lympectomy. I have been cancer free for six years. My mother had breast cancer as well. I now need a MRI with contrast. I am a RN, but of course I am concerned. What can cause the shadowing on the ultrasound? I do have dense breasts, fibrocystic disease and saline bilateral implants behind the muscle. What are your thoughts please? Thank you!
DCI(stage 0) is a precursor lesion for breast cancer, meaning if left untreated it progresses to Cancer.That's why it is surgically removed, and adjuvant treatments are offered to prevent its recurrence and father progression to breast cancer. Coming to your question, Having dense breast tissue, fibrotic disease and saline implants leads to varying tissue density, the shadowing can be a result of that. An MRI with contrast and breast coil is recommended to get complete information as the normal tissue is disturbed by surgery and implants.  Nevertheless, a 50 % chance of malignancy is present in normal woman with such findings. Risk of recurrence in your case is very low. I would also advise you to consult your oncologist regarding continuation of tamoxifen for 5 more years. If you are post menopausal, petamole/anastrazole is advised. Regards