What treatment fields do you use for N1mi breast cancer after lumpectomy/SLNB?

We treat with modified tangents including level 1 and 2 nodes in tangential beam for micrometastases. ER, PR, and her2 neu or oncotype does influence the decision for micrometastases after lumpectomy.

Agree with Dr. @Dr. First Last above. N1mic overall has low chances of regional recurrence even with whole breast only. I typically use high tangents to include the low axillary LNs. However, one should keep in mind that high tangents are more of a logical compromise and no large prospective randomized trials have tested it on protocol. If you are a purist, you would choose whole breast (Z11, even though people cheated), or RNI (AMAROS, OTOASOR, etc). With that in mind, I have on occasion treated N1mic with RNI including an SCV field, but skipping IMN. These are cases with multiple risk factors including but not limited to young age, large primary, inner or central location, LVSI, high grade, patient not getting chemo (many are due to low o...