Jul 7, 2020 09:11PM Beesie wrote:
Well, it's complicated.
DCIS is an "in situ" carcinoma. A DCIS cell is a cancer cell, but it is confined "in place" in the duct and therefore cannot metastasize. Many definitions of cancer include 3 criteria: 1) abnormal cells; 2) uncontrollable cell growth; and 3) the ability of the cells to move to a different location in the body and metastasize. DCIS meets the first 2 criteria, but not the third.
So some experts consider DCIS to be a cancer because the DCIS cell is a cancer cell. But other experts consider DCIS to be a pre-cancer rather than a cancer because DCIS cannot metastasize.
The AJCC staging manual - the American version of staging - includes DCIS as Stage 0 breast cancer. I can't access the full copy of the UICC staging manual - the European version of staging - but from the charts I've seen, while DCIS is discussed and presented identically to what's in the AJCC staging manual, they simply leave out any reference to Stage.
Here is how the American Cancer Society describes DCIS: https://www.cancer.org/cancer/breast-cancer/treatment/treatment-of-breast-cancer-by-stage/treatment-of-ductal-carcinoma-in-situ-dcis.html
"Ductal carcinoma in situ (DCIS) means the cells that line the milk ducts of the breast have become cancer, but they have not spread into surrounding breast tissue.
DCIS is considered non-invasive or pre-invasive breast cancer. DCIS can't spread outside the breast, but it still needs to be treated because it can sometimes go on to become invasive breast cancer (which can spread).
In most cases, a woman with DCIS can choose between breast-conserving surgery (BCS) and simple mastectomy. But sometimes a mastectomy might be a better option."
And this is from the National Cancer Institute: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/ductal-carcinoma-in-situ
"A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, ductal carcinoma in situ may become invasive cancer and spread to other tissues. At this time, there is no way to know which lesions could become invasive. Also called DCIS and intraductal breast carcinoma."
So technically, both answers are correct. DCIS is breast cancer, or DCIS is a pre-cancer. You can choose to call it whichever you prefer, and either way, you will be able to find breast cancer specialists and medical websites that will support what you. My preference has always been that 'DCIS is a pre-invasive cancer'.
What is not in dispute is that DCIS must be surgically removed in order to avoid the development of an invasive breast cancer. Well, maybe a tiny grade 1 DCIS can be watched, there isn't a doctor in the world who would say that a large amount of grade 2 or grade 3 DCIS could be safely left in the breast. What this means is that for those of us who have a large wide-spread area of DCIS (as I did as well), to get all the DCIS out often there is no choice but to have a mastectomy. It is a medically required treatment. That's true no matter how one chooses to define DCIS, as a cancer or as a pre-cancer, and that's what is true in your case.