Post mastectomy Radiation for Close Margin?

[Mandelin Rain]

Otherwise no indication. < 1mm deep and/or <1mm at the skin? NCCN tells you to "consider" radiation if margin <1 mm. What say you?

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[RadOncDoc21]

Otherwise no indication. < 1mm deep and/or <1mm at the skin? NCCN tells you to "consider" radiation if margin <1 mm. What say you?

Never had one myself but this was always something that I just couldn't let go if I had one.

We treat (usually) positive/close margins for pretty much everything else.

 

[Gfunk6]

Depends heavily on surgeon if they feel that they got all the breast tissue. If it was < 1 mm anterior (skin) but patient underwent total mastectomy, then would not treat. If it was < 1 mm deep (pectoral fascia) and surgeon sampled pectoralis muscle/fascia and it was negative, then would not treat.

 

[medicinewoman101]

Otherwise no indication. < 1mm deep and/or <1mm at the skin? NCCN tells you to "consider" radiation if margin <1 mm. What say you?

MDACC has a retrospective on this issue that is worthwhile to take a look at. I know you said no other indications but the number of indications that need to be considered may be larger than you think. That study is useful to look at; ill see if I can dig it up

 

[Palex80]

Depends on surgical technique and location of close margin.

I would recommend it if the margin at the skin was <1mm and it was only a skin-sparing mastectomy. However if it was a radical mastectomy and the close margin site was not at the edge of the resected breast, I wouldn't do it.

I would not recommend it if the deep margin was <1mm and the fascia of the pectoralis muscle was resected and showed no invasion. The fascia is a natural barrier and if it's not infiltrated, then <1mm margin is still good enough.

 

[Mandelin Rain]

Another case....

23 year old.
Multifocal, multicentric T1 disease initially. No clinical or radiographic adenopathy.
Triple Positive
Neoadjuvant chemo/her2 directed therapy
Skin sparing mastectomy + expanders
Small (4mm) residual invasive disease widely excised. Associated DCIS to 1mm of anterior/skin margin. 1 of 10 LN with micromets.
ypT1aN1micMo

Who treats this?

 

[BobbyHeenan]

Another case....

23 year old.
Multifocal, multicentric T1 disease initially. No clinical or radiographic adenopathy.
Triple Positive
Neoadjuvant chemo/her2 directed therapy
Skin sparing mastectomy + expanders
Small (4mm) residual invasive disease widely excised. Associated DCIS to 1mm of anterior/skin margin. 1 of 10 LN with micromets.
ypT1aN1micMo

Who treats this?

Node positive after neoadjv chemo is not a good prognostic sign but I'd still probably not treat. Would blame no one if they wanted to treat that though.

NSABP neoadjuvant chemo B-18/B27 results would suggest a 10 year locoregional recurrence rate of ~11% for ypN+ disease in patients with no clinical node positivity and tumor < 5 cm not receiving post mastectomy radiation- see figure 3A. Not sure how many of those were skin sparing procedures though...but your patient only has 1 isolated node, micromet.

Very tough case. I'd probably wimp out and send to the academic center a few hours away if they're willing to travel for an opinion.

If I did treat I'd probably not cover IM nodes though to help minimize cardiac dose if left sided.

 

[Bequerel]

Node positive after neoadjv chemo is not a good prognostic sign but I'd still probably not treat. Would blame no one if they wanted to treat that though.

NSABP neoadjuvant chemo B-18/B27 results would suggest a 10 year locoregional recurrence rate of ~11% for ypN+ disease in patients with no clinical node positivity and tumor < 5 cm not receiving post mastectomy radiation- see figure 3A. Not sure how many of those were skin sparing procedures though...but your patient only has 1 isolated node, micromet.

Very tough case. I'd probably wimp out and send to the academic center a few hours away if they're willing to travel for an opinion.

If I did treat I'd probably not cover IM nodes though to help minimize cardiac dose if left sided.

Haven't we learned that the curves don't flatten out over time? At a 1%/year risk of recurrence and a life expectancy of more than 60 years, how could you not offer treatment?

 

[Palex80]

Another case....

23 year old.
Multifocal, multicentric T1 disease initially. No clinical or radiographic adenopathy.
Triple Positive
Neoadjuvant chemo/her2 directed therapy
Skin sparing mastectomy + expanders
Small (4mm) residual invasive disease widely excised. Associated DCIS to 1mm of anterior/skin margin. 1 of 10 LN with micromets.
ypT1aN1micMo

Who treats this?

I would.
The problem is, that there was no sentinel node done before neoadjuvant chemo. It's highy probable that before chemo that was not a N1mic but rather macrometastasis in one or more nodes.
If she didn't have the positive node, I'd probably not treat her.
The rather close DCIS margin is not necessarily an indication.

 

[mavrik13]

I would.
The problem is, that there was no sentinel node done before neoadjuvant chemo. It's highy probable that before chemo that was not a N1mic but rather macrometastasis in one or more nodes.
If she didn't have the positive node, I'd probably not treat her.
The rather close DCIS margin is not necessarily an indication.

Agree re: DCIS margin not being an indication. Issue is the node, and high risk LRR with ypN1 disease. I am less sure about ypN1mic.

Would have to spend time digging into the studies but I would be hesitant to lump N1mic into N1 category as well, because this may have been handled differently in published studies (I believe AJCC would not consider N1mic to fall under N1, as N1 requires at least 1 node greater than 2mm).

I would want to know more about pre chemo characteristics of the primary tumour. If it was cT3 then would definitely recommend treatment, but I'm assuming it wasn't. If cT1 pre chemo (even if multi centric) I would feel less strongly about rads, but not enough to decline offering.

Was there evidence of treatment effect in the primary tumour and/or other LN? If there was significant fibrosis in the single positive LN indication treatment effect, would push me stronger to offer RT as it likely was a macromet.

Have to weigh long term s/e risks with her long term risk of relapse. I can't imagine not discussing and offering treatment, letting her know there would be some equipoise with current data, though we know in general neoadjuvant leaves us with a comparatively higher LRR rate and offering with that disclosure. It would be important to consider just based on her age alone, she likely has a completely different biology of tumour compared to the majority of patients on the studies we are used to seeing and extrapolating results from.

The more I think about it, the more likely I would recommend RT. Would be interested to hear other opinions.

 

[medgator]

Gut reaction is to treat, would probably talk with pathologist about whether any treatment effect was seen in the node.

Before treating her, would send out for a second opinion first because it really is a tough case.

As Bequerel stated, local recurrence risk a function of time along with other factors we already know about, which is why I still recommend xrt to some of my 70+ year olds with stage I ER+ cancers if I think they'll flake out on arimidex and they have a good PS and life expectancy

 

[scarbrtj]

Another case....

23 year old.
Multifocal, multicentric T1 disease initially. No clinical or radiographic adenopathy.
Triple Positive
Neoadjuvant chemo/her2 directed therapy
Skin sparing mastectomy + expanders
Small (4mm) residual invasive disease widely excised. Associated DCIS to 1mm of anterior/skin margin. 1 of 10 LN with micromets.
ypT1aN1micMo

Who treats this?

Strong indication to treat. I say "strong" just because NCCN guidelines urge you to "strongly consider" PMRT here. But, philosophically, do we ever weakly consider radiation? Given our life choices, is that possible? Points to ponder.

 

[scarbrtj]

Also, I don't know if a modified radical, non-skin-sparing mastectomy even exists in the wild anymore.