Experience with metaplastic breast carcinoma?

[Pewl]

Hello,

I recently saw a 70y/o lady with a left breast pT2N0 grade 2 metaplastic carcinoma with a tiny invasive lobular component. She had a lumpectomy with widely clear margins and negative sentinel nodes.

Most of the literature I've seen on this essentially treats it as routine breast. Although, I think metaplastic carcinoma counts as a spindle cell neoplasm. Would any of you use a hypofx regimen such as Whelan Canadian or just do standard long course?

Anyone recall any similar cases?

thanks

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[scarbrtj]

Hello,

I recently saw a 70y/o lady with a left breast pT2N0 grade 2 metaplastic carcinoma with a tiny invasive lobular component. She had a lumpectomy with widely clear margins and negative sentinel nodes.

Most of the literature I've seen on this essentially treats it as routine breast. Although, I think metaplastic carcinoma counts as a spindle cell neoplasm. Would any of you use a hypofx regimen such as Whelan Canadian or just do standard long course?

Anyone recall any similar cases?

thanks

*In theory* hypofx was only oncologically equivalent to "long course" because the breast ca alpha/betas were three-ish. (Every single breast hypofx trial was "designed" around this alpha/beta guessworking.) And again *in theory* the more rapidly dividing (and perhaps "aggressive" phenotype) tumors do not have low alpha/betas (making long course better). Also *in theory* long course was the standard of care antecedent all the hypofx studies; metaplastic carcinomas have not been included in any of the hypofx studies, so there is no (similar, randomized) data to show non-inferiority for hypofx here. Hence, long course is still the standard of care for metaplastic br ca. That said, there is no randomized fraction-specific data... so "do what you want" isn't wrong... in theory!

 

[Palex80]

The ASTRO guideline mentions this specific subject.

DEFINE_ME

Histology Statement KQ1H: CF-WBI may be preferred over HF-WBI when treating primary breast cancers with rare histologies that are most commonly treated with conventional fractionation when arising in other parts of the body.
• Recommendation strength: Conditional
• Quality of evidence: Low
• Consensus: 93%
Narrative: Certain rare histologies that arise in the breast are commonly treated with conventional fractionation when they arise in other parts of the body. These include, but are not limited to, histologies such as metaplastic carcinoma, squamous cell carcinoma, sarcoma, and adenoid cystic carcinoma. It is plausible that one or more of these histologies possesses an a/b ratio that is significantly higher than the common breast histologies such as invasive ductal or lobular carcinoma. If so, then treatment with HF-WBI as opposed to CF-WBI could yield a higher local recurrence rate. Accordingly, the task force noted that CF-WBI may be preferred in this setting and noted that the rarity of these histologies makes it difficult to gather high quality data on outcomes with HF-WBI compared to CFWBI.

 

[thesauce]

Hello,

I recently saw a 70y/o lady with a left breast pT2N0 grade 2 metaplastic carcinoma with a tiny invasive lobular component. She had a lumpectomy with widely clear margins and negative sentinel nodes.

Most of the literature I've seen on this essentially treats it as routine breast. Although, I think metaplastic carcinoma counts as a spindle cell neoplasm. Would any of you use a hypofx regimen such as Whelan Canadian or just do standard long course?

Anyone recall any similar cases?

thanks

Terrible pathology. I would treat comprehensive breast and LNs with standard-frac

 

[Palex80]

Terrible pathology. I would treat comprehensive breast and LNs with standard-frac

You would really do that? The patient was pN0.

 

[scarbrtj]

Terrible pathology. I would treat comprehensive breast and LNs with standard-frac

I don't think it's a real lymphotropic (is that a word?) neoplasm. Thus I'd apply my same logic here: the standard of care for metaplastic br cancer that is pT2N0 would be std fx whole breast (and boost!) only. Because there's no randomized data (or any data?) to show treating nodes here does anything. But again... do what you want (of course the case could be "dinged" for sentinel node only here too!... no data)

 

[Pewl]

Thanks for the input. I'm aware of the aggressive nature of the histology, but yeah if the nodes are negative I would lean more toward standard long course whole breast at this time. That PRO article is pretty good.

 

[drewdog1973]

Long course to breast

 

[FrostyHammer]

Terrible pathology. I would treat comprehensive breast and LNs with standard-frac

In a 70 year old? At most if I want to hedge I'd do high tangents, but not more.

 

[thesauce]

I don't think it's a real lymphotropic (is that a word?) neoplasm. Thus I'd apply my same logic here: the standard of care for metaplastic br cancer that is pT2N0 would be std fx whole breast (and boost!) only. Because there's no randomized data (or any data?) to show treating nodes here does anything. But again... do what you want (of course the case could be "dinged" for sentinel node only here too!... no data)

They are usually not node positive, I agree, but I just had one recently with nodal disease. The minimal additional toxicity to add comprehensive nodal is worth it to not regret it.

 

[thesauce]

In a 70 year old? At most if I want to hedge I'd do high tangents, but not more.

Moderately advanced age is inconsequential with bad pathology IMO. Like inflammatory breast. What are you worried about toxicity-wise? If anything, she has fewer years to worry about additional toxicity from adding SCV in the VERY unlikely case that she were have have any.

 

[FrostyHammer]

Moderately advanced age is inconsequential with bad pathology IMO. Like inflammatory breast. What are you worried about toxicity-wise? If anything, she has fewer years to worry about additional toxicity from adding SCV in the VERY unlikely case that she were have have any.

Maybe, but don't ignore that the first prerequisite to having a recurrence is the longevity to be able to experience a recurrence. Early stage metaplastic breast the kind you described is not the same as inflammatory breast. I'm not worried much about toxicities, I'm worried about necessity. If you feel that way about toxicities, then do you treat SCV in every single garden variety T1-2N0 breast cancer meeting MA.20/EORTC22922 criteria? You gotta draw the line somewhere, especially for breast cancer - that's the bottom line.

 

[Palex80]

The minimal additional toxicity to add comprehensive nodal is worth it to not regret it.

 

[scarbrtj]

View attachment 327764

I thought I've displayed... mansuetude. Having a cogent discussion about the risk/benefit of ENI in metaplastic br ca is like trying to get Siri to divide zero by zero.

 

[thesauce]

Maybe, but don't ignore that the first prerequisite to having a recurrence is the longevity to be able to experience a recurrence. Early stage metaplastic breast the kind you described is not the same as inflammatory breast. I'm not worried much about toxicities, I'm worried about necessity. If you feel that way about toxicities, then do you treat SCV in every single garden variety T1-2N0 breast cancer meeting MA.20/EORTC22922 criteria? You gotta draw the line somewhere, especially for breast cancer - that's the bottom line.

No of course not, but with very aggressive pathology (not garden variety IDC/ILC) where there’s not much data to guide therapy and you have an option with only mildly increased toxicity, if any, I would error on the side of being more inclusive.

 

[thesauce]

View attachment 327764

She agrees with me. This is her reaction to leaving off ENI in a metaplastic case

 

[communitydoc13]

Hypofractionated adjuvant radiation therapy of soft-tissue sarcoma achieves excellent results in elderly patients I'd treat the breast only. Not sure that there is much data that hypo for anything is wrong in terms of tumor control and good evidence that toxicity in breast with moderate hypo (13-16) is excellent.

I would stage and restage the patient like a sarcoma however. CT chest in addition to mammograms.

 

[evilbooyaa]

OK to do CF-WBI for this histology. I would not treat nodes in an otherwise pN0 patient. We don't treat nodes electively in non-breast sarcomas anyways, why would a sarcomatomous tumor in the breast be different?

 

[drewdog1973]

Interesting thing is we don't know if CF is better - what if it's actually worse? Who knows?
Surprised folks would treat nodes - wouldn't do it for sarcoma, wouldn't do it N0 breast adeno, wouldn't do it for a breast skin cancer ... so what's the rationale to do it? Just because you can? I think you "can" for pretty much any breast patient, and if that's the rationale, then we probably should treat a lot more patients with RNI! @scarbrtj , you agree?

 

[FrostyHammer]

No of course not, but with very aggressive pathology (not garden variety IDC/ILC) where there’s not much data to guide therapy and you have an option with only mildly increased toxicity, if any, I would error on the side of being more inclusive.

Again, it's not wrong, but I think nearly all the posting docs on this thread (including myself) are nicely in agreement that nodes are probably overkill. Agree that toxicity is low (although lymphedema is still something that can be clearly avoided by not doing RNI) but again it's just likely not necessary since you can convince yourself to do RNI in the majority of early stage breast cases.

 

[thesauce]

Again, it's not wrong, but I think nearly all the posting docs on this thread (including myself) are nicely in agreement that nodes are probably overkill. Agree that toxicity is low (although lymphedema is still something that can be clearly avoided by not doing RNI) but again it's just likely not necessary since you can convince yourself to do RNI in the majority of early stage breast cases.

Yes I do see that and am honestly surprised by the backlash. I have seen metaplastic breast cancer 4 times in 3 years and 2 of those have gone very badly despite having early stage disease at presentation. As a result, I have moved to being more aggressive for this particular pathology. I don't think it's wrong to treat whole breast only (it's what I did for the first case), but I'm just surprised that this is the prevailing thought.

 

[scarbrtj]

When does ENI *truly* change the natural history of any cancerous disease. Prostate? Lung? Sarcoma? H&N (maybe, depends)? ??Breast?? Glioblastoma?

Rad oncs (me too) can be prone to delusions of grandeur, but it appears I have sewn the just-right amount of skepticism re: ENI.

My work here is done.

 

[evilbooyaa]

When does ENI *truly* change the natural history of any cancerous disease. Prostate? Lung? Sarcoma? H&N (maybe, depends)? ??Breast?? Glioblastoma?

Rad oncs (me too) can be prone to delusions of grandeur, but it appears I have sewn the just-right amount of skepticism re: ENI.

My work here is done.

I mean for pT2N0 ductal adeno I'd say the same thing.

I imagine everyone is treating a N+ patient with this histology with RNI. You ain't convinced me of a damn thing, scarb!

 

[Pewl]

I'd like to remind everyone that this patient DID have a 0.2cm component of ILC +/+/-. So, in that sense there is still a classic breast CA involved. But it's such a small amount, like almost an incidental finding. I'm not sure that alone would sway for comprehensive RNI though.

 

[Palex80]

When does ENI *truly* change the natural history of any cancerous disease. Prostate? Lung? Sarcoma? H&N (maybe, depends)? ??Breast?? Glioblastoma?

Rad oncs (me too) can be prone to delusions of grandeur, but it appears I have sewn the just-right amount of skepticism re: ENI.

My work here is done.

Vulva.

 

[scarbrtj]

Vulva.