pT1N1 breast. Omit adjuvant RT

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
R

Ray D. Ayshun

Full Member
Lifetime Donor
Verified Member
10+ Year Member
Platinum Member
Joined
Sep 7, 2014
Messages
3,489
Reaction score
6,429
Members don't see this ad.
Figured I'd start another breast is the worst discussion. It's easy to extrapolate from various trials to it being reasonable to omit whole breast in certain pT1N1 breast cancers s/p lumpectomy and SLNB. I'm wondering if anyone is doing this much/if there's any good data specifically addressing this scenario.
 
Ray D. Ayshun said:
Figured I'd start another breast is the worst discussion. It's easy to extrapolate from various trials to it being reasonable to omit whole breast in certain pT1N1 breast cancers s/p lumpectomy and SLNB. I'm wondering if anyone is doing this much/if there's any good data specifically addressing this scenario.
Click to expand...

Wait there isn’t an omission trial looking at this specifically? I’m shocked.
 
a0p0d7.jpg
 
Ray D. Ayshun said:
Figured I'd start another breast is the worst discussion. It's easy to extrapolate from various trials to it being reasonable to omit whole breast in certain pT1N1 breast cancers s/p lumpectomy and SLNB. I'm wondering if anyone is doing this much/if there's any good data specifically addressing this scenario.
Click to expand...
I assume you mean cN0/pN1 here. And isn’t no SLNB the SOC for most low risk breast presentations now. Don’t let inappropriate sentinel LN biopsying ruin a woman’s chance at less toxic RT has kind of been my motto but I’m open to be corrected. Similarly don’t let following the SOC of no SLNB ruin a woman’s chance at less toxic RT.
 
I wouöd not skip adjuvant RT of the breast in this scenario, I am not aware of trials showing it can be skipped.

It is possible, that giving more PBI without SLNB in the future will lead to more „out-of-PBI-volume“ recurrences in the future. Tumor cells travel from the tumor to the SLN through lymph vessels that are (partially) within a WBI-volume.

Having said that, and despite the absence of evidence, I am open to give PBI in a patient without SLNB wirg favorable tumor biology.
A European trial is currently preparing to open, testing PBI without SLNB. It will also ommit AI.
 
Even import lo allowed pN1. Yes, just 4%. Point being, someone's thinking about doing this It seems like doing partial breast to a 75:yo woman with a low grade strongly er/pr+ pT1N1 should be expected to have same OS as omission. Im sure there's a LRR benefit, but thats never stopped omission. I get how nontoxic this is, I'm just wondering where we're headed.
 
Ray D. Ayshun said:
Even import lo allowed pN1. Yes, just 4%. Point being, someone's thinking about doing this It seems like doing partial breast to a 75:yo woman with a low grade strongly er/pr+ pT1N1 should be expected to have same OS as omission. Im sure there's a LRR benefit, but thats never stopped omission. I get how nontoxic this is, I'm just wondering where we're headed.
Click to expand...
A lot of peeps happy to give them years of AI though
 
TheWallnerus said:
I assume you mean cN0/pN1 here. And isn’t no SLNB the SOC for most low risk breast presentations now. Don’t let inappropriate sentinel LN biopsying ruin a woman’s chance at less toxic RT has kind of been my motto but I’m open to be corrected. Similarly don’t let following the SOC of no SLNB ruin a woman’s chance at less toxic RT.
Click to expand...
Yes, this too. There is a substantial number of pT1NX women with a met lounging in the axilla who aren't getting adjuvant RT.
 
Ray D. Ayshun said:
Even import lo allowed pN1. Yes, just 4%. Point being, someone's thinking about doing this It seems like doing partial breast to a 75:yo woman with a low grade strongly er/pr+ pT1N1 should be expected to have same OS as omission. Im sure there's a LRR benefit, but thats never stopped omission. I get how nontoxic this is, I'm just wondering where we're headed.
Click to expand...
I think where we are headed is you will never know if a 75yo with strongly ER positive low grade is pN1, we won’t care, and we will give them 5 fraction PBI. Have any of you started seeing women (especially 70+yo women) whose surgeon followed INSEMA? Do you let pNX cause a change in RT management?

Palex80 said:
It is possible, that giving more PBI without SLNB in the future will lead to more „out-of-PBI-volume“ recurrences in the future. Tumor cells travel from the tumor to the SLN through lymph vessels that are (partially) within a WBI-volume.
Click to expand...
But if this were possible/true wouldn’t we have seen a signal of increased axillary recurrences, or out of volume PBI recurrences, in IMPORT LOW or Livi?
 
TheWallnerus said:
But if this were possible/true wouldn’t we have seen a signal of increased axillary recurrences, or out of volume PBI recurrences, in IMPORT LOW or Livi?
Click to expand...
Well, these patients all had SLNB. And almost all of them were negative.
 
Palex80 said:
Well, these patients all had SLNB. And almost all of them were negative.
Click to expand...
Correct me if I’m wrong but there was no hint of different axillary recurrence rates in MA20 (treated axilla) vs EORTC 22922 (didn’t treat axilla). No differences in SUPREMO. No difference in axillary recurrence in Z0011. No difference in axillary recurrence with whole breast versus partial breast. No difference in INSEMA.

It’s fine to have theories and or worries, but in the face of something crazy like one hundred thousand patient-years of data eventually cold hard reality is at risk of taking hold: the axilla is not an impactfully therapeutic site in clinical stage one breast.
 
TheWallnerus said:
Correct me if I’m wrong but there was no hint of different axillary recurrence rates in MA20 (treated axilla) vs EORTC 22922 (didn’t treat axilla). No differences in SUPREMO. No difference in axillary recurrence in Z0011. No difference in axillary recurrence with whole breast versus partial breast. No difference in INSEMA.
Click to expand...
You are talking about trials where the axilla was surgically staged. This is a different scenario.

We are omitting axillary staging.
We are trying to ommit adjuvant AI therapy.
We are going from whole breast to partial breast.

All at the same time.

You see the issue we are going to face with the axilla?
 
Last edited:
Palex80 said:
You see the issue we are going to face with the axilla?
Click to expand...
Can I say this is fear mongering without being sassy or snarky. Probably not. As Gary Busey says “FEAR… false evidence appearing real.”

People have been saying “you see the issue” all the way back to the days when surgeons swore that abandoning mastectomy for lumpectomy was going to lead to “disease en carasse.” Rad onc Cassandras have been prophesying about the axilla for two decades now. Cassandra looking more like Chicken Little after all the trials I mentioned above. Do we remember when proper surgical staging equaled axillary dissection. Now we know that low risk stage one breast patients have a cancer cell in the marrow about as commonly as they have a cancer cell in the axilla left behind after SLNB alone.

To give a 75yo woman with low risk breast cancer treated a la INSEMA whole breast RT instead of PBI because of worry about the axilla is wild stuff!
 
Last edited:
I am not advocating to give WBI instead of PBI in a patient treated without SLNB.
I think you can give PBI.

Do I think recurrence rates are going to go up, if we ommit

- SLNB
- adjuvant AI
- WBI and give PBI instead

All at the same time?

Yes, I do.

But likely, some oncotype-like-test will pop up in the future, which will allow us to make those calls.
 
TheWallnerus said:
Just learned that at least in Europe pNx a contraindication to PBI 🙁

Highlights from Breast Cancer Radiotherapy Sessions at ESTRO 2025

About ESTRO work
www.estro.org www.estro.org
Click to expand...
Let's just say, this is an "expert opinion", not definetely something I would follow blindly.

For instance, a close margin is also considered a contraindication to APBI, but I never fully understood why.

If the positive margin is well defined and within the APBI volume, why is this a contraindication?
A positive margin increases the risk for a local failure. Period. It does not increase the risk for a failure somewhere else in the breast or the lymphatics.
 
Last edited:
Palex80 said:
Let's just say, this is an "expert opinion", not definetely something I would follow blindly.

For instance, a close margin is also considered a contraindication to APBI, but I never fully understood why.

If the positive margin is well defined and within the APBI volume, why is this a contraindication?
A positive margin increases the risk for a local failure. Period. It does not increase the risk for a failure somewhere else in the breast or the lymphatics.
Click to expand...
Do you have data to support the statement that positive margins do “not increase the risk for a failure somewhere else in the breast…”? I have looked at some of the older studies and they do not clarify the exact location of these failures. It’s always seemed crazy to me that we go from APBI to whole breast + 16 Gy or higher boost for a positive margins when it seems like you just need to increase the dose locally at the tumor bed/+margin. Wish we had data to back this up
 
Desrazita said:
Do you have data to support the statement that positive margins do “not increase the risk for a failure somewhere else in the breast…”? I have looked at some of the older studies and they do not clarify the exact location of these failures. It’s always seemed crazy to me that we go from APBI to whole breast + 16 Gy or higher boost for a positive margins when it seems like you just need to increase the dose locally at the tumor bed/+margin. Wish we had data to back this up
Click to expand...
A little crazy. Check.
 
Desrazita said:
It’s always seemed crazy to me that we go from APBI to whole breast + 16 Gy or higher boost for a positive margins when it seems like you just need to increase the dose locally at the tumor bed/+margin. Wish we had data to back this up
Click to expand...
I wish we did have data to back it up.

A positive margin is not an indicator of bad biology, it is merely an indicator of a bad surgeon.

happy birthday GIF
 
alwaysbeIMRTing said:
If you have a 1 mm margin instead of a 2 mm margin, just increase CTV margin from 1.5 cm to 1.6 cm.

</mic drop>
Click to expand...
Pretty sure the ESTRO HDR or some brachytherapy society has an similar approach in their guidelines. The margin width subtracted from some fixed width. It is a totally rational idea
 
I've seen that rule being applied for the CTV-margin around the boost-"GTV" [15mm-resection margin], so it likely makes sense.
 
You must log in or register to reply here.

Similar threads

R
Rationale for timing of adjuvant RT after surgery: breast and prostate
Replies
32
Views
3K
evilbooyaa
evilbooyaa
Kroll2013
  • Poll Poll
Adjuvant RT for early stage adenocarcinoma of the cervix
Replies
8
Views
1K
seper
S
Palex80
Adjuvant vs Salvage RT in Prostate cancer.... again
Replies
18
Views
1K
evilbooyaa
evilbooyaa
R
Breast De-escalation
Replies
11
Views
1K
evilbooyaa
evilbooyaa
Palex80
Breast is the worstest x5?
2
Replies
84
Views
3K
communitydoc13
C
Top