Please explain how DCIS can be invasive? Confused!

weerah

Hi Everyone,

I'm new here. Last Tuesday, I was diagnosed with DCIS but the biopsy showed some cells have invaded the breast tissue. My mass is 8.6 cm, so I'm pretty happy that it's so early, but if the cancer has left the ducts, doesn't that make it IDC? My surgeon says to consider this very early in the diagnostic process and we'll know more after the mastectomy, but I'm confused. I thought DCIS wasn't invasive. Can someone explain? Also, what questions should I make sure I ask my doctor when I see her next (she's on vacation for two weeks)?

Thanks so much!

Beesie

DCIS cannot be invasive.  

However, the natural progression of breast cancer development is that DCIS cancer cells evolve to become invasive cancer cells.  When the cancer is found at the point where all the cells are still DCIS (i.e. still confined to the milk ducts), the diagnosis is DCIS, Stage 0.  When the cancer is found at the point after some of the cells have evolved to become IDC, the diagnosis is IDC, Stage I (or higher, depending on other factors).  

Because of the way that cells progress from DCIS to IDC and because not all of the cancer cells progress or evolve at the same pace, it's very common to find IDC and DCIS together.  When they are found together, because IDC is the more serious condition, the diagnosis, staging and treatment is all based on the pathology of the IDC.  The DCIS that was also present will be adequately treated by whatever is done to treat the IDC.

In my case, I had well over 6cm of DCIS and only 1mm of IDC.  An IDC tumor that small is called a microinvasion and this type of breast cancer is called DCIS-Mi. Because it's not pure DCIS, because of the presence of that tiny microinvasion, the staging is Stage I. 

I hope that makes sense. 

weerah

Thanks so much Beesie. That makes a lot of sense. I'm a little confused about the diagnosis because my doctor called it DCIS but then said they found cancer outside the ducts, and due to the size of the mass, they won't know more until it comes out. I just don't understand why she called it DCIS though. Maybe because it looks like I have more DCIS than anything else?

Beesie

So many of us are told that DCIS with a microinvasion is rare, and I read that in lots of reports & articles about DCIS too.  However from what I've seen on this board over 5 years, DCIS-Mi actually seems to be pretty common-place. There are lots of us here who've had that diagnosis. 

I've read that approx. 10% - 15% of women initially diagnosed with DCIS end up with DCIS-Mi. I wouldn't be surprised if the number is higher.  But even if it's only 10%, with approx. 60k cases of DCIS diagnosed in North America every year, it means that 6,000 of us are diagnosed with DCIS-Mi each year.

The good news is that with the exception of needing to have an SNB (an SNB is optional for someone with pure DCIS), usually the presence of a microinvasion doesn't change the treatment plan.  And fortunately the prognosis barely changes.  With the presence of any amount of invasive cancer there is a risk of distant recurrence (i.e. mets) but for those who have only a microinvasion, this risk is very small. 

cinnamonsmiles

Beesie, I have a question about your posts and DCIS cells. Is it that DCIS cancer cells are different than IDC at the cellular level? Or are they cellularly the same but  location within the breast that is the only difference?

Beesie

mycinnamon, the answer is "both". DCIS cancer cells are different from IDC cancer cells at the cellular level and DCIS cancer cells are confined to the milk ducts whereas IDC cancer cells are found in the open breast tissue. 

To the second point, this graphic from breastcancer.org shows how DCIS cancer cells evolve to become IDC cancer cells as they break through the milk duct and enter the open breast tissue.  In the DCIS drawing, you can see that all the cancer cells are confined to the milk duct.  In the DCIS-Mi drawing, just a few of those cancer cells have broken through the duct wall.  In the IDC drawing, more cancer cells have moved outside the duct and they are multiplying and spreading.  What you can also see in the IDC drawing is that there still are some DCIS cells - cancer cells confined to the milk duct.  So this drawing shows how it is that so many women are found to have DCIS and IDC together.

http://www.breastcancer.org/pictures/types/dcis/dcis_range.jsp

To the first point, my understanding is that when breast cancer cells are examined under a microscope, it is possible to identify DCIS from IDC cells - regardless of where the cells were found (in the open breast tissue or in the milk duct).  While DCIS cancer cells have about 90% of the characteristics of IDC cancer cells, they lack the ability to break through the duct and survive in open breast tissue.  It's when this final molecular change takes place, giving the cell that ability to break through the duct, that DCIS begins to convert to IDC.  That's how I understand it.

What this means is that if you have a biopsy and some DCIS cells are accidentally dropped into the open breast tissue, or if during surgery some DCIS cells are moved to a lymph nodes by the surgical instruments, these cells don't become IDC and start spreading.  While not exactly the same situation, my case provides a good example of this.  I had two areas of DCIS that were surgically removed.  The pathology report indicated that both areas had high grade DCIS with comedonecrosis (the most aggressive DCIS there is); a microinvasion of IDC was also found (i.e. one tiny area of my DCIS had already started to become IDC).  The pathology report also indicated there were no clear margins anywhere. Thanks to the margin situation, I had to go back into surgery but until I did, I was walking around with a breast full of  cut open milk ducts full of high grade DCIS. For various good reasons, I didn't have my next surgery for 2 1/2 months.  My final pathology report from this second surgery showed lots more high grade DCIS throughout my breast but there was no IDC, not even another microinvasion.  So none of the DCIS that was in my breast and that had the opportunity to spill into the open breast tissue, became IDC. My case is just one example but over the years I've seen lots of women with DCIS who've had dirty margins and I'm hard pressed to think of anyone who was found to have IDC when they had their re-excision (the second surgery).

Some info about DCIS cancer cells: 

Evidence that molecular changes in cells occur before morphological alterations during the progression of breast ductal carcinoma   CONCLUSIONS:  We identified new genes that are potentially involved in the malignant transformation of DCIS, and our findings strongly suggest that cells from the in situ component of lesions with co-existing invasive ductal carcinoma exhibit molecular alterations that enable them to invade the surrounding tissue before morphological changes in the lesion become apparent.

Current Treatment and Clinical Trial Developments for Ductal Carcinoma In Situ of the Breast  Pathologically, DCIS is described as a proliferation of malignant-appearing cells that have not invaded beyond the basement membrane and is distinguished from IBC by being limited to existing ducts and lobules. It carries malignant potential based on the lesion's size and histologic
grade. The Wellings and Jensen model of the evolution of "ductal carcinoma" shows the natural progression and histological continuum from hyperplasia to IBC, with DCIS immediately preceding invasive cancer. This model suggests that an accumulation of molecular
changes results in an invasive phenotype.

SuziePA

My situation is similar.  The pathology report from my mastectomy last month was DCIS and the one lymph node they took was clear.  When they were doing the hormone receptor staining a few days later, they found under 1mm of IDC and changed my stage to T1mi.  The doctor told me the IDC was so small that the course of treatment did not change.  No chemo or radiation.  I just have to go back in 6 months for a mammogram on the "good" breast and yearly after that.

weerah

So I've just had another appointment with my oncologist and now I'm even more confused. I have a very large mass (8.6 x 6.7) and as I said the biopsy came back as DCIS with some IDC cells in the sample. I asked my doctor how my lump grew so quickly (from 0.8 cm last fall when it was misdiagnosed as a fibroadenoma to this thing now) if it's DCIS. She said that she doesn't know what's in this thing because the sample might not be a good representation of what's there.

But she said something else that has me confused. She says you can't feel DCIS. So if it can't be felt, what the heck is this lump?! Beesie, do you know if DCIS is ever palpable as a mass? I'm so confused!

My doctor still says it's early cancer, but how can she say that if she doesn't really know what's there?

MJLToday

Weerah, "early cancer" refers to Stage 1,2, and (sometimes) 3a cancer, so you doctor is saying her best guess is that the cancer has not left the breast and axilla (armpit) area.    That probably can't complete staging until after your surgery.  The biopsy is just a preliminary staging guess.

weerah

Thanks MJL. Maybe I have my terminology mixed up because all of my reading refers to DCIS as "early cancer" but my surgeon has never called DCIS early cancer. She just says I have early cancer. So you're probably right in saying she means it hasn't left the breast. Thanks!

mom3band1g

weerah - DCIS can present as a lump! 

cycle-path

My opinion, after reading many women's posts here, is that docs often say you have DCIS with a microinvasion if MOST of what's found is DCIS. Like, say, 85 - 99%. If it's mostly IDC or if there's a lot of IDC they call it IDC. 

I'd be willing to bet that most women with IDC also have some DCIS but if there's a lot of IDC the DCIS area may not even be mentioned to them.

weerah, while it's unusual to feel DCIS as a lump, it does occasionally happen. It's also possible that you're feeling a fluid cyst or something like that.

Yes, DCIS is a very early cancer. Some doctors even say it's a pre-cancer, though it's much more common to see it referred to as an early cancer. 

Deirdre1

pre-invasive is the best term for DCIS IMO... take care

weerah

Thanks for your responses everyone!

cycle-path- it's not a cyst. It's always shown on imagery as a mass. I also asked the radiologist directly at the time and she said there are no cysts in either of my breasts. This is a mass that measures 8.6x6.7 cm. I also have calcifications in my nipple, which to my doctor shows DCIS is present and that's why I have bloody discharge. But that's separate from the mass. 

My doctor said that this could be 10% DCIS and 90% IDC and the biopsy just happened to sample the DCIS part. I hate not knowing but my surgery won't be for a while because of the reconstruction. But, I think that if a lump that size is 90% invasive, wouldn't she advise against reconstruction until after we know? She seems so nonchalant about the whole thing. 

Anonymous

This has been a great thread of useful information for me.  I was dx'ed with LCIS in the Right breast about 6 years ago.  I did the careful monitoring-MRI's, needle biopsies when indicated and tw excisions.  Nothing was ever found in the left breast.  Long story short:  I decided, after getting a second opinion, to have a PBMX 3 weeks about.  The pathology report showed DCIS in my left breast.  My BS said they got very clear margins and no need for chemo or radiation.  I've been a little anxious about that because it seems that the women I know who have had DCIS have all had radiation and some chemo and radiation.  After reading all of this information, I now am wondering if many of us get the terminology wrong (i.e. DCIS vs. IDC).  I have a follow up appt. with my BS on the 22'nd and will get my final answers, but the information here has certainly helped to allay most of my anxiety.  Thanks!  Pat