Skin/Fascia Margins for IDC

curveball

My tumor is at the very edge of my breast in the armpit. The MRI shows it very close to both skin and fascia. I am leaning toward mastectomy because I do not want to have radiation treatment. At first I thought my surgeon said, unless the tumor had invaded skin or fascia, no radiation would be required with mastectomy. The tumor moves around freely and the skin does not seem to be attached either, so I felt reasonably confident about not needing radiation. I spoke with her on the phone Monday, and now she says, if the tumor is "too close" to the skin and/or fascia, radiation treatment would be given, even after mastectomy.

Is there any generally accepted standard for how close is "too close"? Or is it completely the individual doctor's opinion? The surgeon keeps recurring to this point of "you may have to have radiation treatment even with mastectomy", but I don't know if I will be able to get a specific answer either about how close is too close or how probable she thinks it that my tumor is within that limit. I pretty much expect to get a nebulous, evasive response.

Are there any statistics about what percentage of women end up with rads after mastectomy due to the tumor being close to skin and/or fascia? Can a radiologist give me a more definite idea of how much clearance there is, by looking at my MRI or other scans?

I searched breastcancer.org, but the only threads I could find about margins between skin or fascia and cancer were in the DCIS forum. 

LouLou40

I had 2 tumours one just below the skin and one deeper that wasn't palpable.

I opted for a lumpectomy as they were close together, the path came back post surgery showing positive subutaneous margin (skin margin) and 1mm anterior margin (chest wall). My tumor felt as you described, didn't feel attached to the skin.

My BS didn't recommend any further surgery as Rads would mop up cells in the margin.

I asked my BS, MO and RO if I had a mastectomy could I opt out of rads as I wasn't keen on Rads when I feeling exhausted during chemo and was thinking of just having the mastectomy instead.

All said NO with involved skin margin rads would be recommended regardless and a closs margin also called for rads.

gracebead

My 1cm IDC was sitting on my chest wall (riaght breast at 10 o'clock), leaving me with less than 1mm margin after mastectomy.  The surgeon took out the fascia, but 2 RO's are recommending radiation therapy.  I was so disappointed, but after some research, I learned that there is a real benefit of radiation for people with a very close margin.

Because of the mastectomy, my RO can't really pinpoint the exact site where my tumor used to be (they say after mastectomy things get moved around before they suture you up), I need to get whole breast radiation without booster.

Therefore, mastectomy does not necessarily guarantee you that you won't need radiation.  I think if other parts of your breast is clean and lumpectomy is your preference, then it might be easier for the RO to localize the radiation.  It would be a good idea to ask the surgeon if she can scrape the chest muscle to get a better margin (very aggressive approach), but I think it's really hard to pinpoint the site of tumor during the surgery.  Wish you the best outcome!!