In Situ

I had a breast biopsy in January of this year and the pathologist report came back "In Situ Carcinoma".  Just what exactly does "In Situ" mean?  and I always thought carcinoma means cancer, however, my doctor said no.  He also recommended a follow up exam with him every 6 months and a mamo every year.  I now have occassional burning in that breast but I don't feel any lump, thank God.

[CCF-RN,MSN-JS]

Dear The, In situ cancers of the breast are confined within the lining of the ducts or lobules.  These are early cancers or pre-cancerous lesions that have not developed the ability to become invasive.  There are generally two types of in situ breast cancers.  Ductal carcinoma in situ (DCIS) do have the ability over a long period to become invasive cancer if untreated.  So these tumors have to be completely removed.  They usually affect only one area in the breast.  

Lobular carcinoma in situ (LCIS) tends to be thought of as a marker for the risk of developing cancer.  Since LCIS tends to reflect risk in both breasts, it is not usually possible to remove all of the tumor without removing all of both breasts.  This is excessive treatment in most situations, so very careful follow-up is often recommended after removal of the in situ lesion.