Metaplastic Carcinoma: Understanding a Rare Breast Cancer

Question
Hi

My mother has been diagnosed with Metaplastic Carcinoma, I know that you have been asked this before, but wondered if you had any further info in it.

We were told that it was a 'strange' cancer, and that is was not as such a 'breast cancer' however was found in the breast....They also said that due to the fact that my mother has had a previous breast cancer in the same breast and had Radiotherapy in that breast as a result, there was a possibility that the Radiotherapy was the cause of the MP carcinoma.  They also said that it is also possible that they have stumbled upon the secondary cancer site and that there is a primary site, they will soon carry out a Mastectomy and are unable to confirm which until examination of the removed breast has occured.   Also to note, my mother has had 3 other primary cancers in the last 22 years, none invasive until this one, they were Cervical, Breast and Kidney.  

Answer
No, not really. A metaplastic cancer MAY be radiation induced. That is unfortunately a risk you must take with radiation therapy - since the overall risk goes down so much thanks to the therapy. But as you have been told it MAY also come from somewhere else - rare but possible. We will not know which until after surgery - if even then! She has been most unlucky with regards to cancer, but the first 3 - if this is her 4:th have been unrelated to each other as far as I can understand. I'm sorry I can not contribute more! I do hope all goes well!