Are there any accruing trials in the U.S. evaluating selective use of radiation after mastectomy in early stage breast cancer?  

I have yet to see results from the SUPREMO trial investigating this question in Europe.

There is the EXPERT trial, NCT02889874 based in Australia/New Zealand, and the PMRT-NNBC study, NCT02992574 based in India that appear to be looking at this question. 



Answer from: Radiation Oncologist at Academic Institution