Should I choose 15 or 5 radiation treatments for early stage breast cancer?

I was given the option of 15 radiation treatments or 5 day at higher dose. I also have osteopenia and have not received any bone treatment since diagnosis 1 year ago. I also have spinal stenosis. I’m looking for any input on the 15 day vs the 5 day radiation plan and input on the hormone blocker therapy to start after radiation. I have stage 1, grade 2 mixed ductal and lobular carcinoma and also in one area DCIS stage 0.