So 5 days is usually a higher dose. I had 600 cGy each day for total of 3000 cGy. In 2022 it was fairly new, and radiation was sequential 5 days.
I had newest tech, hypofractionalized, breath controlled, varying doses with highest level at cancer target.

I don’t usually share this, but because you’re just”asking pun intended”, you might want to know that while 5 days results in fewer immediate skin issues, that doesn’t mean the higher dose doesn’t cause trouble. 2 years after radiation I had another surgery to the radiated breast. I was very thankful that while doing so the surgeon cut out a lump of hardened tissue that over time had started hurting when i laid on my side, radiation caused. The finished outcome also wasn’t as nice as the original surgery because 2 years later my skin had thickened and was not as pliable. It appears that they struggled a bit to get the thickened skin to shape nicely and the sutures looked like they were pulling a purse string. I don’t think this was lack of surgical skill. I also have a seroma along that area because the skin just was difficult to get flat at the sutures.

Its 1 1/2 years since last surgery. Although the breast looks fine, that tight suture area gets sore by the end of the day. I feel lumps and bumps in the radiated area. I keep my fingers crossed that it won’t harden anymore.

So yes, there may be reasons women want lower doses over more days. If I were having a mastectomy or further surgery after radiation I’d definitely check whether the outcomes over time would end up better with the longer radiation plan. My experience is that it might be better.

15-16 smaller radiation doses might not have caused this issue. I guess we can only wait and see how the 5 day higher dose looks in 10-15 years.

Honestly your “pun intended” affects women everywhere who tried to make the best decisions on the knowledge they had at the time.