My advice would be to find a physio who specialises in bone health and stay off drugs for as long as possible. I am 76 and recently had chemo and radio for an aggressive estrogen driven breast cancer. So have to take anastrazole, which is bad for bone health. Medical oncologist says I need to take it for several years. After 6 months with the physio my bone density has improved significantly - although am still diagnosed with osteopenia. Twice a week. Now lifting 24K kettlebells and doing 50K on the leg press. Means I don't need to walk much- chemo caused peripheral neuropathy, so walking isn't pleasant.