Would you offer postmastectomy re-irradiation in a patient with locally advanced, ER-/Her2+ disease with pathologic complete response after neoadjuvant chemo?

Our threshold for PMRT for reradiation is high because the therapeutic ratio changes. Stage III her2 neu positive non inflammatory breast cancer treated with dual her2neu therapy with pCR would avoid RT.

I would consider based on initial clinical staging and previous RT (breast only vs. breast +RNI). If unfavorable features beyond path CR, I would offer re-irradiation which would include chest wall and regional nodes. If previous dose to SCV, I limit to 45/25 additional to stay under 100 Gy cumulati...

This is an area where there is a paucity of data. My own belief is that re-irradiation should rarely, if ever, be used prophylactically for patients without gross residual disease after surgery. I have yet to see firm evidence on exactly what modalities, fractionation scheme, total dose, and field s...