New breast is the worst case. Just saw a 39 yo with a BRCA mutation who had what was called a cT2N2 ER+ PR-/HER2- breast cancer. This was in the setting of a biopsied 4.6 cm primary and an MRI with 7 abnormal-appearing axillary nodes, none of which were biopsied. Got neoadjuvant chemo followed by lumpectomy and ax dissection. Final staging was ypT1aN0. Residual primary was 1.5 mm with treatment effect noted. 0/17 nodes with no treatment effect noted. For reference, an abnormal node noted on initial MRI went from 1.7 cm to 1.1 cm on repeat after NACT. Wondering if anyone would do whole breast only, or even just observe (based on age, what we know about CR to NACT and genetic predisposition to cancer). My plan as of now is RNI despite only circumstantial evidence of axillary involvement.
First off - new breast is the worst discussion means that it needs its own thread. Posts have been moved. Robust discussion pretty quickly...
Going to start by just reading the OP:
By cN2, I presume you mean the nodes were matted? Because nodal count doesn't matter for clinical staging. If NOT matted nodes, than she meets B51 criteria. If she has matted notes, then she is too high of risk to be enrolled on B51 (only enrolled cN1 patients) and thus I would definitely treat breast AND nodes.
Assuming she is actually cN1 (numerous nodes but NOT matted, can't remember a time I've truly seen a patient with matted notes), then she meets enrollment criteria for B51. B51 globally was negative, but showed lower HR in patients with ER+, Her2- disease. I would participate in shared decision making with the patient regarding pros/cons of B51 data in terms of treating WBI alone vs WBI + RNI. Especially with 17 resected (and negative nodes), I would have a hard time strongly pushing for RNI despite patient's young age and BRCA mutation. I would verify on CT sim that the 1.1cm node was removed at time of surgery and not left in place. If still present, would consider biopsy, and if positive, then RNI w/ boost.
I would NOT observe after a lumpectomy. B/L MRMs, sure can observe.
Going through the remaining posts:
Left. I don't disagree. This is the worst bc surg/med onc decided to forgo evaluating the axilla with a biopsy. The not mature results of B-51 notwithstanding, RNI is still SOC as far as I can tell for cN+ disease. I'm put in the position of altering the staging prior to NACT despite meeting her 8 months later.
I think waiting for 10-year data in a trial omitting RT is not unreasonable, but I think it is worth a discussion with the patient and some shared decision making regarding pros and cons of the data, similar to how we do shared decision making to discuss potential omission of WBI in 65-70+ year old women w/ early stage IDC.
Would you use 10 year data? (NB: the nature of actuarial analyses makes 5y outcomes
highly predictive of 10y outcomes for two large randomized group comparisons.) Would seem just as suspicious to do so for anyone with a "50 year life expectancy." So you should be safe from any results from B51 for the rest of your career, even a 20 year update. (wink)
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You didn't use "a standard" or "
the standard," so I don't disagree but...
RNI still means "treat the IMNs, plus other things," to me. And IMNs are VERY CONTROVERSIAL (see above). So to call IMN RT "standard" in a 39yo who's ypN0 and has a left-sided cancer... maybe not "standard." In addition, even the NCCN (just) says "strongly consider RNI" for this case. Thus,
rather standard...
quite standard... not-so-"standard," period. Especially in light of B51 and experts openly stating "
At our institution, we will be omitting regional nodal irradiation in most patients who meet the criteria for [B51]." A standard is an evolving thing, or should be.
Comparing Rabinovitch's slide which is a discussion of comparing one RT regimen to another is not an equal comparison to thinking of outcomes between omission of RT vs delivering RT. See PRIME and CALGB for pretty significant differences in numerical risks of recurrence between 5 and 10-year data.
And 'MOST patients who meet criteria' may not include a 39yo w/ BRCA mutation with ER+/Her2- cancer (the MOST likely to benefit from RNI as per 5-year B51 results) double digit visible nodes pre-op (would be pN3 if she went for upfront surgery and this wouldn't even be a discussion then).
Alright fine, whole breast. Boost?
100% yes in my practice.
Did your practice change
In short, yes.
In long: MOST patients with N1 disease s/p NACT showing pN0 do not need RNI. I would advocate against it specifically in TNBC and Her2+ patients.
In a ER+/Her2- patient I would have shared decision making regarding that there may be some relative benefit, but the absolute benefit at 5-years is probably relatively minimal, with the caveat that chances of recurrence in ER+ breast cancer increase all the way up to, if not past 10 years, and we don't know how to interpret previous 10-year data in the neoadjuvant chemotherapy era. So a patient who wanted all maximally potentially beneficial therapy, yeah I'd do RNI. In one who was more of a minimalist, I would think omission to be very reasonable.
Would anybody's recs change if the case I mentioned was triple negative?
Yes. TNBC specifically had worse outcomes WITH RT, likely because they are such a good biology group of patients to respond to systemic therapy (as opposed to those who don't sterilize the nodes).
No, I would still treat nodes.
The person who trained me would not enroll TNBC on 1304 fwiw.
The screw up here was failure to confirm cN+ disease by biopsy.
To continue to do things simply because of "that's how I was trained" and ignore a randomized clinical trial which can, in no terms, suggest that RNI is beneficial to TNBC N1 patients who receive NACT and are ypN0, and suggest that RNI may be actively harmful (like a 39-yo getting IMN RT and CAD risk).... that's something I can't wrap my head around.
You had dogma. Now we have evidence stating that the dogma was wrong. We still gonna follow dogma?
I’m usually able to meet all constraints using VMAT and could even omit nodes if needed to in order to meet constraints. One could also advocate for protons in this situation. Basically, if you’re able to meet every constraint, would it still be an issue or is the evidence to support RNI just not that strong to even consider it for a possibly “higher risk patient” even if we have not been able to determine who those patients are at this point.
Personally, I lean more towards the treatment side just because I think the risk of side effects is not that high vs a possible recurrence (although small). I’m not a strong advocate and like I said before, I can be swayed either way.
Protons to put her at higher risk of rib fracture and worse skin reactions? No thanks. Proper 3D or VMAT, likely w/ DIBH (hoping this 39-yo can tolerate it). Cover IMNs above the level fo the heart given no obvious pre-op involvement.
Regarding the case above, patient was clinically N2 and would therefore not qualify for b51. I would treat breast and undissected nodes.
cN2 by number is NOT a thing. Specifically based on location or matted nodes. If she has matted notes, I agree. One could have 11 nodes suspicious pre-NACT but still could be very easily N1.
