What are your thoughts on the relevance of sentinel lymph node biopsy before the onset of neoadjuvant chemotherapy for HER2+ or triple negative cT2+N0M0 breast cancer patients?

Nodal staging changes radiation fields, but given increasing pertinent null findings of a positive SLNBx with regards to outcomes, I wonder if ypN0 is the most important prognostic indicator - an indicator that would be lost if SLNB was done pre-chemo.