Hi @aj456, I guess you have probably made your decision but for what its worth I also had high grade DCIS and went ahead with the radiotheraphy. As I had 3 wide local excisions to get clear margins supposedly there wasn't time to do the DCISionRT before losing any benefit of radiotheraphy. Pretty much all I read on it indicated the reduction in recurrence was worth any side effects or risks and I only had to have 15 shots. The relevant study is NSABP B-17 trial which you can find online if you are so inclined to read up on the research (effectively halves the risk). I have also been recommended to take Tamoxifen however as my ER status was only borderline positive I am less convinced at least for now to pursue this. All the best.