Just dx'd

Hi Caryl C - So sorry you have reason to join us here.  There is a poster named Beesie who also has DCIS - Microinvasion who may be along to have some more helpful information.  Basically from my (limited) understanding, the microinvasion means that some of your DCIS has developed the ability to invade through the milk ducts into the rest of the breast tissue at the microscopic level. ((hugs)) to you and hopefully someone more knowledgeable will be along soon.  Also, there is (right underneath this forum I think) a DCIS with microinvasion thread

Caryl, I have DCIS with a microinvasion too.  The presence of the microinvasion means a few things:

• As soon as a microinvasion is found, this moves you up to Stage I from Stage 0. Only pure DCIS is Stage 0. A microinvasion is considered to be a T1mic tumor and that's automatically Stage I (or higher, should more invasive cancer be found).   
• With any amount of invasion, even just a microinvasion, there is the possibility of nodal involvement. Whereas DCIS cancer cells cannot move outside of the breast to the nodes (or beyond into the body), invasive cancer cells can. Even though the risk of nodal involvement is low (about 10% for those who have microinvasions), it means that your lymph nodes definitely have to be checked. So while a sentinel node biopsy is optional for those who have pure DCIS, for those with microinvasions, an SNB is necessary.  This means that when you have your surgery, you will have an SNB as well.
• At this point you've only had a stereotactic biopsy, correct? With the presence of the microinvasion, there is the possibility that more invasive cancer might be found when your surgery is done.  This is unlikely but it's something that you should be aware of.  If this should happen, then your staging and treatment will be based on whatever amount of invasive cancer is found and the pathology of that invasive cancer.
• If all that is found is 1-3 microinvasions (areas of invasive cancer that are 1mm in size or smaller) along with the DCIS, then your treatment is unlikely to change vs. what it would be if you had pure DCIS.  I had one microinvasion and my treatment didn't change at all. Chemo is not indictated for those who have only one or a few microinvasions; similarly, if you are HER2+, Herceptin normally is not given to those who have just microinvasions.
• If all that is found is 1-3 microinvasions along with the DCIS, then your prognosis barely changes from what it would be if it was pure DCIS.  In this forum you often read about women being really frightened that a microinvasion will be found, because a microinvasion is invasive cancer.  It's true that a microinvasion is invasive cancer, but it's the earliest stage at which invasive cancer is diagnosed.  And if all you have is 1-3 microinvasions, then your diagnosis and prognosis will be a lot closer to DCIS than to a more advanced Stage I breast cancer (with a T1b or T1c sized tumor, for example).  It is true that as soon as any invasive cancer is found, mets becomes a possibility (and yes, that is scary) but for those with a microinvasion, I was told by my oncologist that the risk is only about 1% or less. Obviously that's not as good as 0% (which is what the risk of mets is for those with pure DCIS) but it's the next best thing.

With my microinvasion, my diagnosis is Stage I.  Although I sometimes post in the Stage I forum, with over 7cm of high grade DCIS with comedonecrosis and only 1mm of IDC, I have a lot more in common with the women here in the DCIS forum and I tend to spend most of my time here. I think most of us who have microinvasions do tend to see ourselves more as having DCIS than having IDC, simply because our treatment and prognosis are closer to DCIS women go through than most who have invasive cancer.

Hope that helps.