Was your DCIS located near the chest wall? I think it’s one of their concerns is that the ribs or lungs might take a hit if they are radiating close to that area. My lesion was right there near the rib on the lower outer quadrant. Now I look back and think how blithely I made the decision to not have another surgery to fix the 1 mm margin, and chose radiation. I think I’d still make the same decision - but experience is knowledge, and as much as I researched beforehand there were gaps in what I thought, and what is.

Do you mind sharing what type of radiation you had? Whole breast? Partial? hyper-fractionalized?
I had a total 30 gy, which is less than what others may have had. Mine was VMAT (volume modulated arc therapy).