Should nodal fields be added to post-mastectomy radiation treatment after neo-adjuvant chemotherapy if there is a CR in the nodes?

There is no good study for this clinical situation. NSABP is conducting a trial where pts who have pCR in clinically positive nodes are being randomised to regional RT vs. no regional RT. In practice, I usually treat for patients with pretreatment clinical N2 disease or have inflammatory breast cancer. The threshold to treat is lower if they have sentinel node biopsy only as the false negative rate is higher.