Do you offer RNI to a T1N0 breast cancer patient who underwent inadequate axillary dissection?

I would not do RNI but include level 1 and 2 nodes for inadequate assessment of axilla with a tangential field for BCS.

In patients undergoing mastectomy who are T1N0 with inadequate axillary sampling (no SLN, few LN taken), I do not offer RT even with triple-negative, grade, LVSI unless positive margin though I do discuss the possibility of higher rates of LRR than a luminal A patient.

In patients undergoing lumpectomy with the same situation, I would offer the whole breast and not include RNI. Though there is some consideration for RNI in high-risk node-negative patients, I do not routinely offer this.

In the name of playing Devil's Advocate (or initiating a nerd fight club), I'll provide an opposition view on "is it ever appropriate to cover RNI for pT1N0?" (irrespective of LND adequacy, & excluding neoadjuvant therapy).

Situations for data suggest which it may be reasonably considered/discussed, with rationale & caveats:

1. UIQ/LIQ, particularly with multiple intermed risk features (age, grade, LVI, TN / ER-): While 90% of pts in NCIC MA.20 were pN+ (& remainder pT2+; NEJM 2015;373:307), nearly half (45%) of patients in EORTC 22922 were pN0 (mdn LN yield 13-15; Table S2), as eligibility include stage I-III pts with medial tumors (NEJM 2015;373:317). Interestingly, the 10y magnitude of benefit (3% DFS / 3% dDFS / 2% LRC) were very close to...

Covering Level I and II are sufficient.

@Dr. First Last @Dr. First Last @Dr. First Last. I have a case along a similar topic that I would love your thoughts on:

The patient is a female in her late 20s with left breast IDC, strongly ER+ PR+ Her2-, poorly differentiated of lower outer/central quadrant, 5:00 5 cm FN. Upfront breast MR without evidence of axillary or IMNs. She is s/p lumpectomy and SLNBx showing pT1c disease (1.8 cm) poorly differentiated, DCIS 2.0 cm (non-extensive) grade 2, extensive LVSI+, PNI+, 0/3 sLNs (axillary), Ki67 25-30%. Close posterior margin <0.5 mm (excision included pectoralis fascia). Oncotype Dx RS 14 (4% risk of distant recurrence at 9 years, <1% benefit from chemo); chemo not recommended with plan for tamoxifen 20 mg x 5-10 yrs. To make this more i...