Another case of borderline indication for PMRT: Yes or No

[Kroll2013]

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Dear Colleagues,

Does this patient needs PMRT +/- RNI ?

52 years old patient with bilateral breast IDC.
right : cT2N0
Left: cT2N1
She received neoadjuvant chemotherapy , with very good response.
Followed by bilateral radical mastectomy.

she obviously needs PMRT + RNI to the left side.
but the question is about the right side where pathology showed: focus of fibrosis, consistent with previous tumor site in complete response to treatment.
all margins are free, nipple shows chronic inflammation, no evidence of residual viable carcinoma. ER ++, PR+, Her-2 neg.
one positive axillary sentinel node over 1 dissected : 3mm tumor deposit with no evidence of extra-capsular extension nor treatment effect.

is any adjuvant radiation needed to the right side?

 

[w00tz]

I would. Although minimal, she still has residual disease in the right axilla after NACT. If she had 3mm disease without chemo, then I might omit.

 

[RSAOaky]

B-51 is a clinical trial looking at women with a clinically positive axilla who undergo neoadjuvant chemotherapy and have a complete response in the axilla. The standard post-mastectomy arm in this trial is RNI and the experimental arm is no additional treatment.

This patient has a PR in the axilla post-NAC and mastectomy. She wouldn't even qualify for B-51. The standard of care is PMRT.

 

[Mandelin Rain]

Radiate away.

 

[scarbrtj]

PMRT bilaterally with sclav RT as the only "RNI." If I were a woman I would not choose the increased risks (lung toxicity, edema, etc) of sizeable (ie IMNs/axilla/sclav) RNI compared to its benefits. Especially were I a young woman of 52. Whatever the standard PMRT risks are, this is a case where I personally think they're at least approximately doubled. Size of tx volume correlating to toxicity is one of the truest truisms in radiation oncology.

 

[evilbooyaa]

Yup, need to PMRT + RNI Right side.

Can evaluate IMC coverage as part of RNI based on initial location of tumors and potential dosimetry - would be OK to omit.

I, personally, never omit axillary RT in a patient who got only a SLNB, as this patient did (at least on the right)

What was her response in L breast? Probably not eligible for B-51 with bilateral disease but that'd be a disease question (assuming her left axillary lymph node was negative).

 

[OTN]

Yes from me as well.

 

[scarbrtj]

Yup, need to PMRT + RNI Right side.

Can evaluate IMC coverage as part of RNI based on initial location of tumors and potential dosimetry - would be OK to omit.

I, personally, never omit axillary RT in a patient who got only a SLNB, as this patient did (at least on the right)

What was her response in L breast? Probably not eligible for B-51 with bilateral disease but that'd be a disease question (assuming her left axillary lymph node was negative).

A hypothetical resident somewhere is asking, "Her risk of IMN relapse is higher than risk of axillary relapse--which is generally the site (among distant, contra breast, ipsi breast, sclav, IMNs, axilla) with lowest risk of relapse--but we'd consider omitting IMNs yet always try to tx axilla?"

 

[Mandelin Rain]

A hypothetical resident somewhere is asking, "Her risk of IMN relapse is higher than risk of axillary relapse--which is generally the site (among distant, contra breast, ipsi breast, sclav, IMNs, axilla) with lowest risk of relapse--but we'd consider omitting IMNs yet always try to tx axilla?"

I'd let the resident know that they are demonstrably incorrect.

MA20 non-RT group: Included among regional recurrences were 14 involving axillary nodes, 8 involving supraclavicular nodes, 1 involving infraclavicular nodes, and 1 involving multiple sites.

MA20 RT group: Included among regional recurrences were 5 involving axillary nodes and 1 involving multiple sites.

 

[OTN]

I'd let the resident know that they are demonstrably incorrect.

MA20 non-RT group: Included among regional recurrences were 14 involving axillary nodes, 8 involving supraclavicular nodes, 1 involving infraclavicular nodes, and 1 involving multiple sites.

MA20 RT group: Included among regional recurrences were 5 involving axillary nodes and 1 involving multiple sites.

We also have randomized data (from France if memory recalls correctly) showing no benefit to the addition of IMLN RT to regional nodal and CW RT after mastectomy.

 

[Mandelin Rain]

If I remember correctly, wasn't there a total of 2 or 3 excess isolated IMN recurrences in the non-irradiated groups of the two trials combined?

 

[evilbooyaa]

We also have randomized data (from France if memory recalls correctly) showing no benefit to the addition of IMLN RT to regional nodal and CW RT after mastectomy.

Ten-year survival results of a randomized trial of irradiation of internal mammary nodes after mastectomy. - PubMed - NCBI - The French study reference above - 2D techniques (unclear from abstract their exact timeline), unclear the benefit with updated techniques. Low patient numbers (powered for 10% survival difference, which is very optimistic given results of EORTC/MA-20). Most (31.5Gy) dose given by electrons (not overtly common in current age IMO) in all patients

With more updated techniques? (from 2003 to 2007) - DBCG-IMN: A Population-Based Cohort Study on the Effect of Internal Mammary Node Irradiation in Early Node-Positive Breast Cancer. - PubMed - NCBI - benefit to IMN RT but issues of whether R-sided or L-sidedness is a confounder

I think inclusion of them (sometimes, always, or never) is just valid variations in practice.

 

[medgator]

I chase imns when I can if the plan won't look terrible. Otherwise, I ignore them unless positive.

That's my evidence based approach

 

[Palex80]

Irradiate bilaterally