PATH REPORT-What does it all mean?

My mom had a mammogram that showed a 8mm lesion - she had a core needle biopsy, we just received the path report, could you tell us what this all means?

Infiltrative Ductal Adenocarcinoma, 1.2 cm, Moderately Differentiated (Tubule Formation 2/3, Nuclear Grade 2/3, Mitotic Grade 1/3, For a Histologic Score of 5/9) with Focal Ductal Carcinoma in Situ (Solid and Cribriform). Margins of Excision Negative for Malignancy.

Is this really aggressive? How did it go from 8mm on the mammo to 1.2 cm so quick? What treatment will be necessary?

She has to have a Sentinol Node Biopsy next week. This is all so horifying - all the waiting, etc.   Thank you.

[CCF-RN,MSN-rf]

Dear TORE:  From what you write, it sounds as though your mom had an excisional biopsy - the tumor has been removed.  I doubt if the tumor grew.  I would imagine that the view on the mammogram simply did not detect the largest dimension.  Remember, its a difference of 4mm which is very small.  Also, in the setting of breast cancer, 1.2cm is still considered a small tumor.  Based on the pathology, this is a moderately aggressive tumor.  The good news is that the margins (or edges of the surgery) are negative - that means no more breast surgery other than the lymph node excision.  Treatment will be determined by several factors, including lymph node status, estrogen/progesterone receptor status, as well as the opinion of the physician.  Without knowing more, the only treatment I would commit to would be radiation therapy, since she had a lumpectomy only.  If she were to have a mastectomy, no radiation therapy would likely be necessary.