Looking for stat's DCIS with mastectomy and close margin

Carolyn,

I am in exactly the same position as you (see my previous post called 'Tight Margins Post-Mastectomy). I had, in March 2009, what I thought was a prophylactic bi-lateral mastectomy after the margins from my breast conserving surgery last Sept 2008 came back with narrow margins all around. Well, the margins are narrow again on my mastectomy (<1mm on the posterior aspect and 2mm on the inferior, with DCIS everywhere in the left breast). I just saw the radiation oncologist today and she is recommending radiation, with a probable local recurrence of 15% if I opt out. Radiation cuts that in half. I am also 32 years old with a mother who died of BC at 50, which all played into her recommendation. I have tissue expanders in, and am going to consult with my plastic surgeon to do all we can to avoid complications on the reconstruction while going ahead with radiation. I have been told that the radiation is not urgent and I have time to wait. The radiation oncologist will be discussing with my plastic surgeon whether to expedite the exchange to permanent implants (which is only supposed to be in 2.5 months from now), and to wait for the healing from that surgery before going ahead with radiation. Let me know if you get any additional opinions. I find it very difficult to be in this situation of having had, what many would consider a radical surgery, and still finding myself in a fairly high recurrence bracket.

Carolyn,

My situation was similar to yours.  I had a lot of high grade DCIS and my closest margin after my mastectomy was my anterior margin, which was 1mm.  I expected that radiation would be necessary but both my surgeon and my oncologist agreed that radiation was not required.  As it was explained to me, if invasive cancer is that close to the margin, then radiation is required because after a mastectomy there always will be tiny amounts of breast tissue left and if the margins are that small, there could be invasive cancer left in the remaining breast tissue.  But DCIS exists only within the milk ducts and after a mastectomy, even though some breast tissue may remain, it's unlikely that any milk ducts will remain.  That's why margins of about 1mm after a mastectomy are usually considered adequate for those of us with DCIS, and radiation usually isn't recommended.  There have been lots of women who've come through this board with close margins after a mastectomy and I'd say that about 90% were told that radiation wasn't necessary.   

Even with my close margin, I was told that my recurrence risk was only 1% - 2%.  I did read a study recently that put the recurrence risk at a higher number for those who have DCIS and have margins of 2mm or less after a mastectomy, but it was nothing like 50% - 60% - if I recall, it was more in the range of 10%.  That study included situations where there were negative margins - no margin at all - and I'm guessing that the cases with negative margins probably had the highest recurrence rate and probably brought the average up.   For me, even if I'd been told that my recurrence risk was 10%, I don't think I would have opted for radiation, which would have cut the recurrence risk by 50%.  For me, a 5% risk reduction would not have been worth it, since 10% is already, to me, acceptably low (it's lower than the risk that the average women faces to get BC). 

And here's something else to consider.  With no breast tissue to hide in, if you have a recurrence, it is likely to be noticeable quite quickly, either as a lump under your skin or on the scar line.  That was something that my surgeon explained to me.  With implant reconstruction, one of the benefits is that a recurrence often can be caught quickly because the chest muscle is right behind the skin, with nothing in-between. So a recurrence either on the chest muscle or under the skin will be quite quickly noticeable. 

Despite the recommendation of both my surgeon and my oncologist, I was a bit nervous about it.  Since most recurrences of DCIS that occur on the skin occur at the scar line, and since my pathology report seemed to indicate that my closest margin was near the incision, when I had my exchange surgery, replacing the expander with the implant, I asked my PS to remove a bit more of the skin on both sides of the incision.  So I figure I took care of the close margin by doing this.  This is something that you might want to consider, if you are uncomfortable with the closeness of the margin but would prefer not to have radiation.

I just had a bi-lat mast with not great margins.  Posterier margin was 1mm and anterior was less than 1mm.  My bs said I will need rads.  She said if I didn't she was confident it would come back.  I have  my first meeting wth a rad onc April 20th.  I really thought with the mast that would be all the treatment I would need. 

weety, you quoted me right, which is that I said that "it's unlikely that any milk ducts will remain".  But it's not impossible.  If it was impossible, there would be a 0% recurrence rate after mastectomies for DCIS.  But the recurrence rate is actually 1% - 2%, and higher for those who have really close or negative margins.

Milk ducts run all through the breast.  Usually when the breast tissue is scrapped off against the chest wall during a mastectomy, there won't be any milk duct tissue left but there's no guarantee of that.  This is why those who have negative or dirty margins after a mastectomy for DCIS usually get radiation, even if it's only DCIS in the margin.  Recently, because of the study that I referenced in my earlier post, it seems that radiation is being recommended more for those who have 1mm margins, although back when I was diagnosed (4 years ago), this was rarely seen.  I think the point of my post was that with close margins for DCIS, there is a risk of recurrence, but it's nothing like the 50% - 60% risk that Carolyn was told.

Late to the party but for those who had dirty DCIS margins,  how much radiation was recommended? Specifically in regards to boosts? I have seen 2 radiation oncologists and one said definitely boosts bc of dirty margins, age (30), and high grade, while the other said no.   So they are sending it for a third opinion and then I am supposed to pick.   I have mild lymphedema already and am worried about the extra risk of it increasing with more rads. Anyone have a similar situation?